Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design Balanced Cantilever Bridge PART – I Method Statement for Construction of Balance Cantilever Segments of Balanced Cantilever Bridge Page - 1 PART – II Method Statement for Construction of Open Foundation, Piers and Superstructure of Balanced Cantilever Bridge Page - 51 PART – III Method Statement for Construction of Hammer Head at the Fixed Pier of Balanced Cantilever Bridge Page - 77 PART – IV Method Statement for Construction of Tack Coat and Bituminous Concrete for Balanced Cantilever Bridge Page – 102 References Page – 111 A Technical Paper by Sandipan Goswami (References are given at the end of this document, Page 111, followed by Design Summary with AASHTO, BS/Eurocode2 and IS/IRC) To master the concept the Analysis and Design of a Balanced-Cantilever Bridge default sample design data may be processed by downloading software ‘ASTRA Pro Premium’ from website www.techsoftglobal.com. ` ‘ASTRA Pro – Premium’ software provides a set of (100+) Sample Editable CAD Drawings for construction of Balanced Cantilever Bridge. Learning concept for “Model Analysis-Design-Construction” Foreword Article on Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design This article contains the ‘Method Statement’ about the work sequence for the construction of Open Foundation, Piers and Superstructure of Balanced Cantilever Bridge. For the design the software ‘ASTRA Pro Premium’ is used, and a set of editable sample drawings are provided with software ASTRA Pro Premium, this software may be downloaded from its company website www.techsoftglobal.com. After downloading the software may be installed in the system. The software provides analysis, design on analysis and sample editable CAD drawings under the section ‘Drawings’. In analysis suite, there are ‘Normal Analysis’, ‘Stage Analysis’ and ‘Dynamic Analysis’, out of these analysis the ‘Normal Analysis’ is mandatory other analyses are optional. The ‘Stage Analysis’ is also known as Non Linear Analysis or P-Delta Analysis or Force Deflection Analysis. The analysis may be carried out for 5-stages each shall be of 20 years. If the design life of the bridge is 100 years then each five stages will give forces and deflections by applying Dead Load, Superimposed Dead Load and Live on the deflected shape of the previous stage. Initially (immediately after construction) if the allowable deflection for a bridge span is ‘Span/1500’ that is to be tested by on-site load test on the bridge. If the deflection is within span/1500 then the load capacity rating capacity is partly alright. Next, upon unloading the bridge span in stages if the deflection recovery is found up to 85%, then the load capacity rating capacity is finally alright. This load test is to be conducted after 20, 40, 60, 80, and 100 years of age of the bridge, if the respective deflections are within the values found by stage analysis then the condition of the bridge is alright at that respective ages, otherwise other tests as NDT may be carried out and decision may be taken whether to go for rehabilitation or replacement of the bridge. The deflection may by deformation in the superstructure, substructure or bearing and that may be observed by reading from sensors attached at strategic locations of the bridge. Next, user has to go to section ‘Design Forces’ in ASTRA Pro and select ‘Normal Analysis’, and then select ‘Design on Analysis’ to get the design results in respect of selected design forces. The sample CAD drawings may be edited as necessary, as per user’s design data and the design results. The design reports in AASHTO-LRFD, BS/Eurocode2 and IS/IRC are given, at the end of the ‘Method Statement’ and next the ‘References’ are given to assist the users further. Sandipan Goswami Email: sandipanmails@gmail.com Academic Text Book with Real Design Applications Text Book title: Computer Aided Bridge Engineering, Author: Sandipan Goswami, Pages: 381, Publisher: Nova Science Publishers, New York, USA, ISBN: 978-1-68507-413-5 Publisher, for Book, Software and Tutorial videos, Web page: https://novapublishers.com/shop/computer-aided-bridge-engineering-detaildesign-of-pre-stressed-concrete-i-girder-box-girder-bridges/ Contact: Ms. Lisa Gambino, Nova Science Publishers, for price discount offer, Email: marketing@novapublishers.com Ref. Sandipan Goswami, (Author) Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami PART – I Method Statement for Construction of Balance Cantilever Segments of Balanced Cantilever Bridge TABLE OF CONTENTS SL. NO. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. SECTION NAMES PAGE NO. SCOPE OF WORK INTRODUCTION RESPONSIBILITY CODES AND SPECIFICATIONS MATERIALS REQUIRED RECORDS AND DOCUMENTATION REFERENCE DOCUMENTS / DRAWINGS MAJOR EQUIPMENTS WORK SEQUENCE SAFETY PRECAUTIONS AND MEASURES 1 2 2 4 5 5 6 7 8 49 1. SCOPE OF WORK Location Start Chainage (Km) End Chainage (Km) Length (m) Balance Cantilever portion Foundation Piers Hammer Heads (at fixed & free piers) Pier caps (at free piers) Spans Balance cantilever segments Stitch segments Extended portion Foundation Piers Abutments Pier caps / Abutment caps Spans Area Name and District Name. LHS RHS Total 2634km+122.5m 2634km+082.5m 2635km+397.5m 2635km+377.5m 1275 m 1295 m 13 13 13 13 26 26 12 12 24 5 10 (98.00 m) 4 (53.75 m) 200 10 5 10 (98.00 m) 4 (53.75 m) 200 10 10 400 20 6 4 2 6 4 (20.00 m) 7 5 2 7 5 (20.00 m) 13 9 4 13 9 28 1 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 2. INTRODUCTION This Method Statement describes the construction sequence of Balance cantilever segments of Balanced Cantilever Bridge superstructure by Cantilever Form Traveler (CFT). It also describes the methods adopted, equipments, material details and relevant IS codes, inspection details and safety and health measures. 3. RESPONSIBILITY i. Supervisor shall be responsible for managing all equipment, machineries and workmen for all subsidiary activities. ii. Section Engineer/Manager shall be responsible for all activities of the works including reinforcement cutting/bending/fixing, Shutter fixing and concreting works. iii. Execution Engineer shall be responsible for the works as per the technical specifications & drawings. iv. QA/QC Engineer shall be responsible for ensuring the quality of work as per specifications. v. Survey Engineer shall be responsible for ensuring correct alignment and elevation of structure as per the drawings. vi. Safety Engineer shall be responsible to ensure safety of workers during the progress of work. vii. Planning engineer shall be responsible for ensuring the work is going as per Schedule and planned sequence / methods. viii. Project in charge shall be responsible for overall completion of Project within time. 2 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-1 (A) & (B) - General Arrangement Drawing of Viaduct-2 (Longitudinal Elevation, Reference Drawing: GAD-01) Figure I-2 - Cross section of balance cantilever segments (Reference Drawing: GAD-01) 3 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 4. CODES AND SPECIFICATIONS Construction is covered under Specifications for Roads and Bridges (MoRTH) 5th Revision as below (Relevant standards may be followed for construction in different countries): Sr. No. Section 1 1000 Clause Materials for Structures Clause 1006 - Cement, 1007 – Coarse Aggregate, 1008 – Fine Aggregate, 1009 - Steel, 1010 - Water, 1011 – Timber, 1012 – Concrete Admixtures, 1014 – Storage of Materials, 1015 – Tests and Standard of Acceptance 2 1500 Formwork 3 1600 Steel Reinforcement 4 1700 Structural concrete 5 1800 Prestressing 6 1900 Structural Steel 7 2300 Superstructure IS:1343 – Pre-stressed concrete Code of Practice, IS14268 – Uncoated stress relieved Low Relaxation Seven ply strand for pre-stressed concreteSpecification, IRC-18-200 – Design criteria Pre-stressed Concrete Road Bridge (Post tensioned Concrete). 4 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 5. MATERIALS REQUIRED Materials required for construction of the Balanced Cantilever Bridge is to be as per relevant specifications. However, for cross reference the relevant Indian standards are given as follows: Materials Used Source Cement Ambuja OPC 53 grade, Ultra Tech OPC 53 grade, or other approved make. Water Reinforcement Water from Bhawli Dam M/S SAIL & M/S JSW Coarse Aggregate Stone Crusher Crusher Sand (Wash Sand) Admixture Concrete Crushing aggregate excavated from site Crystalline Admixture, Corrosion Inhibitor Batching Plant Sheathing ducts Anchorages HT Strands Specifications IS 4031 -1988, IS 4032 -1985, IS 12269 - 1987 As per IS - 2000, IS 3025 As per IS 1786 :2008 As per IS 383-1970, IS 2386 1963 As per IS 383 IS 9103 IS 456: 2000 EFNARC Morth Specifications Section 1803.2 Morth Specifications Section 1803.3 IS14268 6. RECORDS AND DOCUMENTATION Sr. No. 1 2 3 4 5 6 7 Documents Material and Mix design approval Request for Inspection Inspection Check List Approval to Place concrete Concrete Batch Slip Concrete Pour record Stressing record 5 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 7. REFERENCE DOCUMENTS / DRAWINGS (Available with ASTRA Pro Software) Drawing Nos. 01 (1 OF 3) GAD 01 (1 & 2) SUPERSTRUCTURE 08 (1 to 4) SUPERSTRUCTURE 02 (1 & 2) SUPERSTRUCTURE 09 (1 to 4) SUPERSTRUCTURE 10 (1 & 2) SUPERSTRUCTURE 11 (1 to 3) SUPERSTRUCTURE 12 (1 & 2) SUPERSTRUCTURE 13 (1 to 3) SUPERSTRUCTURE 14 (1 & 2) SUPERSTRUCTURE 15 (1 to 3) SUPERSTRUCTURE 16 (1 to 2) SUPERSTRUCTURE 17 (1 to 3) SUPERSTRUCTURE 18 (1 & 2) SUPERSTRUCTURE 19 (1 & 2) SUPERSTRUCTURE 20 (1 to 3) SUPERSTRUCTURE 21 (1 to 3) SUPERSTRUCTURE 22 (1 to 3) SUPERSTRUCTURE 23 (1 to 3) SUPERSTRUCTURE 24 (1 & 2) SUPERSTRUCTURE 25 (1 & 2) SUPERSTRUCTURE 26 (1 to 4) SUPERSTRUCTURE 05 (1 to 6) SUPERSTRUCTURE 06 (1 to 3) SUPERSTRUCTURE Description General Arrangement Drawing Dimension details of Monolithic Span Reinforcement Details of Monolithic Pier Head, Seg. S1 Dimension Details of Free Pier Span Reinforcement Details of Free Pier Head, Seg. S1 Reinforcement Details of Segment S2 in All Spans Reinforcement Details of Segment S3 in All Spans Reinforcement Details of Segment S4 in All Spans Reinforcement Details of Segment S5 in All Spans Reinforcement Details of Segment S6 in All Spans Reinforcement Details of Segment S7 in All Spans Reinforcement Details of Segment S8 in All Spans Reinforcement Details of Segment S9 in All Spans Reinforcement Details of Segment S10 In All Spans Reinforcement Details of Segment S4 of Anchor Span Reinforcement Details of Segment S5 of Anchor Span Reinforcement Details of Segment S6 of Anchor Span Reinforcement Details of Segment S7 of Anchor Span Reinforcement Details of Segment S8 of Anchor Span Reinforcement Details of Segment S9 of Anchor Span Reinforcement Details of Segment S10 of Anchor Span Reinforcement Details of Ed1 Segment for all Expansion Joint Piers Pre-stressing Details of Deck Cables In All Spans Pre-stressing Details of Soffit Cables In All Spans 6 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 8. MAJOR EQUIPMENTS The major equipments to be deployed are the followings: Sr. No. Description 1 Pick & carry crane 2 Trailer 3 Crane (min. 150 MT capacity) 4 Concrete pump 5 Transit mixers 6 Curing pump 7 Bar Cutting Machine 8 Bar Bending Machine 9 Welding sets 10 Batching Plant 11 Diesel Generator 12 Compressor 13 Needle vibrators 14 Pre-stressing jacks 16 Power pack 15 Grout pump 16 Survey equipments 17 Cantilever Form Traveler (CFT) 7 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9. WORK SEQUENCE Figure I-3 - Longitudinal Section of Balance Cantilever Segments i. Superstructure construction in Balanced Cantilever Bridge is done by using Cantilever Form Traveler (CFT). ii. The cross-sectional dimensions of segments vary from Segments S1 to S10. iii. Segments of length of 5m are cast by using Cantilever Form Traveler (CFT). Prestressing is done after casting every segment. The reinforcements are continuous through each segment. iv. Segment S1 is cast along with the hammer head on the Pier. Further, from segment S2 to segment S10 are cast by using the Cantilever Form Traveler (CFT). v. Segment S2 with concrete volume of around 73 cum. is the biggest segment cast by using CFT and S10 is the Stitch segment, which is the smallest of segment with concrete volume of around 33 cum. The Stitch segment is at the end of a cantilever span on either side, which is at the middle of each span, where it joins the cantilever span that comes from opposite direction from the next pier. 8 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-4 - Section at the end of S2 Segment Figure I-5 - Section at the end of S9 segment vi. To facilitate the CFT operation Sleeve holes of 75mm dia. are to be provided in deck slab as per the sleeve holes drawing. vii. After completion of hammer head, two sets of Cantilever Form Traveler (CFT) are erected on hammer head. viii. Both the CFT sets will cast segments in opposite directions. ix. Two balance cantilever arms are connected by a stitch segment. To cast stitch segment, inner form of CFT is dismantled and conventional shutter arrangement will be provided. 9 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami x. 9.1 Cantilever Form Traveler (CFT) is dismantled after completion of stitch segment casting. Major components of Cantilever Form Traveler (CFT) Following are the major components of Cantilever Form Traveler (CFT) and their weights: i. Main Rails: 6.56MT ii. Main Frames: 6.84 MT iii. Rear truss: 1.69 MT iv. Front truss with hangers: 5.5 MT v. Bottom form: 17 MT vi. Outer form: 16 MT vii. Inner form: 8.5 MT Figure I-6 - Components of CFT Flat and dry area, should be large enough to accommodate the major CFT components, i.e., the bottom form and the outer form will be specified to carryout ground assembly of CFT components before starting the erection work. 10 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami All the assembled CFT components are inspected before starting the erection work. The assembled CFT components are shifted to the lifting location with the help of pick and carry crane and trailer. Erection plan shall be prepared before starting the erection. Parameters such as crane position, boom length, safe working radius and permissible lifting capacity to be decided and accordingly erection activity to be carried out. 9.2 Erection of Cantilever Form Traveler (CFT) a) Main rails: i. The main rails are assembled on ground and lifted on hammer head with the help of crane. Each rail consists of two longitudinal beams (left and right), and transverse connection elements. ii. The main function of rail is to facilitate the advancing of form traveler after every segment casting. iii. While positioning the rails on hammer head the longitudinal slope of rails shall be set parallel to the deck slope (bridge gradient).Whereas in transverse direction both the rails are maintained at same level at every point. iv. Steel packing or wooden packing is provided under the rails for elevation correction. v. The main rails are tied to the deck with rail locking beams by PT bar no 7 as shown in the figure. 11 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-7 - Main Rail Locking with Deck Figure I-8 - Main Rails Locked to the Deck b) Main Frame and Rear Truss: i. Main frame is ground assembled along with ‘Front Under Carriage’ and ‘Rear Tie Down’ assembly. ii. During assembly, care is to be taken that all the pins are secured at the end by cotter pins. The ends of the cotter pins are to be bent properly. iii. The first main frame is erected and positioned on the rails above the deck. Temporary supports are provided to keep the main frame stable and vertical. iv. The crane should hold the main frame until the temporary supports and rear tie down of main frame is completed. v. The rear tie down of main frame with deck is done with the help of PT bar no. 1. vi. The main frame is to be positioned in such a way that the load bearing point is approximately 500 mm behind the hammer head concrete face. 12 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami vii. Second main frame is erected and positioned on the rails above the deck. Temporary supports are provided to keep the main frame stable and vertical. Rear tie down of main frame is done. viii. The rear truss is erected in three parts, central part and two outer parts and it is connected with the main frames by pin connection. ix. A platform is provided along the main frame such that the tip of main frame can be accessed, which will be helpful during the front truss erection. x. Rear under carriage wheels are connected to both the main frames. xi. The rear tie down assembly is secured through the deck using PT bar number 1, bearing plates and nuts are adequately tightened with spanner. It shall be ensured that the tapered washers are positioned correctly. xii. The main function of the rear tie down system is to resist the overturning of form traveler. Figure I-9 - Main Frame and Main Rails 13 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-10 - Rear Under Carriage c) Front truss and hangers: i. Front truss and hangers are assembled on ground and lifted to main frame with the help of crane and connected with main frame by pin connection. ii. Platform provided along the main frame will provide access to do the pin connection between the front truss and the main frame. 14 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iii. Trial assembly of front truss with main frame is to be done on ground to ensure that the front truss and main frame pin connection is perfect. Figure I-11 - Front Truss with Hangers d) Bottom form: i. Bottom form along with side working platforms and rear working platform is ground assembled and positioned exactly below its position on Cantilever Form traveler (CFT). ii. Four chain pulleys each of capacity 10MT are provided to hold the bottom form. iii. Two of these chain pulleys are provided on front truss and two on rear truss. iv. Bottom form is lifted by crane up-to soffit slab of segment and four number chain pulleys are connected. The crane is released only after confirming that all the chain pulleys are taking the load. v. PT bars number 6, two from S1 segment soffit slab sleeves and two from front truss hangers are provided with plates and nuts to hold the bottom form. 15 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-12 - Bottom form: Plan view Figure I-13 - Bottom form: Front view e) Outer form: i. Outside form (median side and ROW side) are pre-assembled on the ground. It consists of support console above which support frames are provided to support the form panels. ii. Casting hangers and launching hangers are provided along with support console. Hangers facilitate casting of segment and launching of form traveler. iii. After completion of ground assembly, the outer form is lifted with the help of crane. It is supported by PT bars, PT bar no. 3 and PT bar no.10 support ‘Outer Form’ through deck slab sleeves connecting ‘Outer Form Hangers’ and PT bar no. 3 from ‘Front Truss Hangers’ holds the ‘Outer Form Support Console’. 16 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iv. The purpose of hangers is to hold the formwork in the correct position during the concreting process. Hangers simplify the setting up and adjusting the formwork. v. Two chain pulleys are provided on ‘Front Truss Hangers’ connecting the ‘Outer Form Support Console’ to facilitate the vertical adjustments in ‘Outer Form’. vi. After erection of ‘Outer Form’ on median side and ROW side, outer vertical web shutter panels are erected and connected with ‘Outer Form’ by pin connection on both the sides. Figure I-14 - Outer form f) Upper working platform: i. The upper working platform frame shall be preassembled on the ground and grating is provided for access. ii. PT bar number 8 (four numbers) is provided from nose truss. iii. The assembly is lifted with the help of crane and supported by PT bar number 8. 17 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami g) Lower working platform: i. The lower working platform is also to be pre-assembled on the ground and lifted in one piece. ii. Two chain pulleys are connected from upper working platform to support lower working platform. iii. The chain pulley is to facilitate the lowering platform along with the bottom form during launching of CFT. iv. Also the lower working platform is to be connected with bottom form by bolts and nuts. Front Transverse Truss Details of the PT Bars as provided in CFT POS. 3 4 6 11 12 12' 13 8 8 Rear Transverse Truss 9.3 POS. 1 1' 3 10 4 5 6 7 11 12 12' 13 Dia. 25 25 36 25 25 25 36 25 25 Dia. 36 25 25 25 25 25 36 25 25 25 25 36 Length (M) 4.0 4.0 8.5 10.0 4.5 5.5 9.0 4.0 6.0 Length (M) 4.0 1.5 2.5 3.0 3.0 3.0 2.0 2.0 10.0 4.5 5.5 9.0 QTY. 4 2 2 2 1 2 1 2 2 QTY. 4 4 4 2 2 2 2 8 2 1 2 1 POSITION Outer Form Supports Inner Form Supports Bottom Form Supports Bottom Form Supports Bottom Form Tension Ties Bottom Form Tension Ties Outer vs Bottom Form Ties Upper working platform Upper working platform POSITION FT Main Tie-Downs Wheel bracket connection leg anchor Outer Form Supports Outer Form Supports Inner Form Supports Inner Form Supports Bottom Form Support Rail Tie-Down Bottom Form Supports Bottom Form Tension Ties Bottom Form Tension Ties Outer vs Bottom Form Ties 18 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.4 Safety Measures During Lifting Operation: i. Crane positioning, boom length, radius and permissible capacity are to be prechecked, i.e., Lifting plan is to be developed and accordingly erection activities are to be carried out. ii. Guide ropes are to be used during erection work. iii. Third party inspection of all lifting tools such as shackles, slings, etc. is to be done. iv. Third party inspection of man basket is to be done. v. During lifting, no person shall stand within the swinging area of boom. vi. Erection sequence is to be explained to all key personnel and workmen involved in the erection activity. vii. Barricade the area covering radius of crane under the load being lifted. viii. Only one person to give signals and shall ensure that all personnel are out of the barricade area. ix. Inspect rigging tools and tackles daily. Damaged/defective rigging tools are to be destroyed to prevent use and are to be removed from the job site. x. No structural member is to be left unsecured. No vertical steel member is to be left standing, unless secured by horizontal members, in a minimum of two directions. xi. All workers must tie/anchor safety hook of Safety Belt. xii. Ensure that the crane and all rigging materials are identified with their SWL and possess a valid load test certificate. xiii. Experienced signalman should be appointed for the task. xiv. Ensure that the lifting points are available on the load, e.g., lifting plates / eye plates. 19 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.5 Installing Hydraulic System of Form Traveler a) Main Jack (J1): i. Each form traveller set has two main jacks located under the main frame at front under carriage. Each main jack is of capacity 200MT, ii. The purpose of the main hydraulic jack is to transfer the loads during the concreting phase to the webs, iii. Before concreting the main jack lifts the equipment off the rails and then the lock nut secures the equipment in position, iv. Packing of sufficient height is provided below the main jack. Figure I-15 - Main Jack J1 under the main frame 20 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami b) Rear Levelling jack (J2) i. The rear levelling jack is provided to ensure that the equipment is in the horizontal position. ii. Rear levelling jack is connected with main frame at rear tie down location Figure I-16 - Rear Leveling Jack (J2) c) Advancing/Launching Cylinder (J3): i. Advancing/Launching Cylinder is provided to shift the form traveller to next segment. ii. After casting the segment, first, the rail is shifted to the next position with the help of advancing cylinder. The rails are locked at new position. Later the form traveller assembly is shifted to new position. 21 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-17 - Advancing/Launching Cylinder Figure I-18 - Location of Jack 22 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami d) Outer form cylinder (J5) and Inner form mechanical jacks (J6): i. The purpose of jack J5 and J6 is to facilitate ‘Shutter Form’ movement. It facilitates shutter alignment before start of reinforcement and in de-shuttering after segment casting. ii. After installing all hydraulic elements, the trail is to be taken to ensure that all the hydraulic elements are performing the intended function. Figure I-19 - Location of Jacks 9.6 Cantilever Form Traveler (CFT) setup for concreting i. The main frame is jacked up by means of the main hydraulic cylinders (J1). The concrete load should not be carried by the wheels of front under carriage. Ensure that the lock-up device on the cylinders is tightened before the concreting operation commences, ii. Horizontal bar of the main frame L4 is into the horizontal position. Align it by using the hydraulic cylinder J2), iii. Ensure that once the form traveler is set up that neither the rear under carriage rollers nor the front under carriage rollers are in contact with the rail. 23 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iv. The rear tie down PT bar umber 1 is tightened. Adjusting and tightening of the shuttering (inner, outer and bottom forms) against the existing box girder at the rear support using PT bars and centre-hole jacks is completed. v. Outer form PT bar number 3 are tightened. vi. PT bar number 11 of the bottom form slab are only loaded during shifting stage. When concreting there will be no load on these bars. During casting the bottom slab is lifted with PT bar number 6. vii. Only one person may be on the cantilevering portion of the platform during casting. 9.7 Outer form alignment and soffit and web reinforcement fixing, Cable profiling i. After completion of installation of hydraulic elements, trial is to be done to ensure working of all the hydraulic elements installed. ii. Shutter alignment is to be done with the help of the surveyor. Levels are to be taken to ensure the longitudinal and transverse slope is maintained as per the drawings. Figure I-20 - Location of PT Bars are to be Stressed 24 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Table: Stressing force in PT bar Sr. No. 1 2 3 4 Location 3 4 6 7 Stressing force 5 Ton 5 Ton 15 Ton 15 Ton Description Outer form rear casting hanger Inner form rear casting hanger Bottom form Rail tie-down iii. After bottom form and outer form alignment, the PT bar connecting casting hangers (PT bar no. 7) and PT bar connecting bottom form (PT bar no. 6) are to be stressed as per the design drawings using hollow jack of suitable capacity. iv. Joint preparation (chipping/hacking) is to be done before starting reinforcement fixing for next segment. v. Reinforcement fixing is to be started after completion of bottom form and outer form alignment. vi. All reinforcement cutting and bending are to be done in the cut and bend yard, as per approved bar bending schedule and approved drawings. vii. Cut & bent steel is to be transported to the fixing location by trailer and unloaded by pick and carry crane. viii. Reinforcements are to be lifted and supplied above the deck by material hoist/crane. The reinforcements shall be adequately tied in bundles and guide ropes shall be used during hoisting. ix. The reinforcements are to be stacked neatly on deck and segregated based on bar mark. Housekeeping is to be done regularly on deck. x. All safety precautions are to be followed during reinforcement lifting operation. xi. Shifting of reinforcement from deck to segment soffit is to be done as per the requirement to avoid area congestion during segment soffit and web reinforcement tying. xii. Reinforcement fixing of soffit and web is to be done as per the approved design and drawings. xiii. After completion of web reinforcement tying, the web cable profiling is to be done as per the ordinates given in design drawings. xiv. Plot all the ordinates and provide tie rod/zig of dia. 10mm or 12mm by welding to place the HDPE duct pipe. Duct pipes are to be placed over the tie rods and U-shape connecting tie bar is to be provided, so that the pipe is locked in position. xv. It is to be ensured that the duct pipes are fixed firmly, and no movement should be allowed during concrete pouring. 25 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami xvi. HDPE duct pipes are connected with couplers with duct pipes in previous segments. xvii. Sealing of duct pipe joints is to be done by using PVC/masking tapes. It is to be ensured that no joint is remaining unsealed. xviii. Bursting reinforcement, Helical reinforcement and End cones are to be provided for cables to be stressed. 9.8 Inner Form Erection and Deck Slab Reinforcement Fixing i. Inner form is ground assembled and erection is done by using crane after completion of soffit and web reinforcement fixing of S2 segment. ii. Inner form support console is erected and supported by PT bar number 4 and 5 through the deck sleeves in S1 segment. From ‘Front Truss Hangers’ the inner console is supported by PT bar number 4. iii. Inner web panel frames with plywood are erected. iv. Deck support trusses are ground assembled along with wooden form panels and are erected with the help of crane. Figure I-21 - Inner form 26 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami v. Inner web shutter panels are connected with the inner deck form and ratchet jack and manually operated spindles are provided for side shifting of inner form as per drawings. vi. Complete the inner form alignment with the help of surveyor. vii. After completion of alignment PT bar number 4 connecting inner form are stressed by a hollow hydraulic jack with a force of 5 MT as per the drawings. viii. Tie rods connecting outer web shutter and inner web shutter are to be provided. ix. Before starting deck slab reinforcement fixing de-shuttering agents are to be deployed on the shutter to ensure ease in shutter lowering. x. Deck slab reinforcement fixing is to be started after completion of inner form alignment. xi. HDPE duct profiling for deck slab cables is to be done along with the reinforcement fixing as per drawings. Fixing of anchorage including bursting reinforcement is to be done. xii. All the duct pipes are to be laid in smooth curves passing through the given ordinates. Suitable spacers/supports at all the important points are to be provided to maintain the profile. Figure I-22 - Deck Slab Sleeve Positions 27 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami xiii. After completion of cable profiling and reinforcement fixing, side shutter for deck slab and segment stopper shutter to be provided, xiv. Sleeve pipes (75mm dia. PVC pipes) are provided asper drawings for Form Traveller operation. Figure I-23 - Sleeve Positions – Sectional View 9.9 Concreting of segment i. Concreting is to be started after completion of the reinforcement fixing and followed by inspection by the Authority’s Engineer. ii. Dummy pipes are to be inserted into the HDPE pipes before starting the concrete operation to avoid damage of HDPE pipes during concreting. iii. The dummy pipe should be moved in both direction during concreting. iv. Before starting concrete cleaning by using blower/manually is to be carried out. Bonding agent is to be applied on the chipped/hacked area of previous segment. v. Approved concrete mix of M50 grade with specified workability is to be produced in batching plant and to be transported to the site in transit mixers. vi. Concrete for segments is to be supplied with concrete pump and pipeline arrangement. 28 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami vii. Before starting concrete operation ensure that the concrete pipe line is free from blockage, viii. During pouring, adequate compaction is to be done by Needle vibrators, ix. Care should be taken that needle vibrator is not placed directly on sheathing pipe, which may damage the sheathing pipe, x. Continuous concrete pouring is to be ensured to avoid formation of cold joints, xi. Segment soffit portion is to be cast first followed by webs and finally deck portion, xii. Web concrete pouring is to be done in a height of 1m alternatively on median side and ROW side, xiii. For deck slab concrete pouring, first deck slab area between the webs is to be cast followed by deck slab area on ROW side and median side, xiv. Concrete top surface is to be leveled as per the desired gradient in longitudinal and transverse direction. xv. Final finishing of top surface is to be done, xvi. After completion of concrete pouring, concrete pump and pipe line is to be cleaned with water to avoid blockage due to setting of concrete, xvii. Concrete curing of all the exposed surfaces is to be done by water/curing compound for 14 days, xviii. Curing of deck slab is to be done either by ponding method or by using gunny bags, xix. Stopper shutter removal can be started after 1 day of concreting, xx. After concrete attains specified strength (35MPa) after 3 days ties rods are to be removed, and outer web shutter de-shuttering is to be done by releasing PT bar number 13. 9.10 Stressing of segment i. Pre-stressing operation is to be carried out only after the concrete attains a minimum compressive strength of 35 MPa or 3 days whichever is later. ii. Dummy pipes are inserted during concreting operation are to be removed. iii. End shutter/stopper shutter is to be removed before start of threading. 29 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iv. HT strands are to be cut in length as specified in drawings by grinding machine, the HT strand cut length includes: a) Anchor to anchor length of cable b) Grip length (820mm) on stressing end c) On dead end 300 mm v. The basic properties of pre-stress tendons are: vi. Threading is to be done by using pushing machine. vii. Bearing plate for 27 DP15 or 19 DP15 is to be provided depending upon the number of strands to be stressed and wedges are to be provided. viii. Insert the strands in the tapered holes provided in the Bearing Plate. ix. Install wedges over the strands and push them into the tapered holes of bearing plate using hollow pipe. x. Actual gauge pressure is to be calculated based on the stressing force values given in drawings and jack efficiency before starting stressing operation. 30 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-24 – Anchor Head 18 DP 15 and Anchor Head 27 DP 15 xi. Elongation values mentioned in drawings are to be modified for actual value of modulus of elasticity and actual cross-sectional area. xii. Stressing is to be done as per the sequence and either from one end or both ends as specified in drawings. Figure I-25 – Wedge for 15.2mm HT strand xiii. Ensure that the hydraulic jack and the power pack are in working condition before making all the arrangements for stressing. 31 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Table: Deck cable Details: Sr. No. 1 2 3 4 5 6 7 8 9 Segment Hammer head and S1 segment S2 S3 S4 S5 S6 S7 S8 S9 Cables to be stressed in a segment C1, C10 & C1’ C10’ C2, C11, C12 & C2’ C11’ C12’ C3, C13, C14 & C3’ C13’ C14’ C4 & C4’ C5 & C5’ C6 & C6’ C7 & C7’ C8 & C8’ C9 & C9’ No. of cables to be stressed in segment 4 6 6 2 2 2 2 2 2 Figure I-26 – Pre-stressing Details of Deck Cables in all Spans 32 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.11 Grouting i. Slip is to be checked after 24 hours of stressing, strands are to be cut approximately 40mm from the bearing plate, ii. Grease is to be applied on inner surface of grout cap, the cap is to be fixed so that the air vent nut is in top position, iii. Cables that are to be grouted are to be cleaned with water and compressed air, iv. Fresh OPC cement and potable water are to be used for grouting operation, v. For grouting, the water cement ratio is to be maintained between 0.4 to 0.45, vi. The temperature is to be maintained during grouting at 25 0C, however in case if ambient temperature is likely to exceed 40 0C, grouting to be done early in the morning or late evening hours, vii. Grout is to be prepared in agitator by thoroughly mixing for 1 min, allow discharge of small quantity of grout through the hose before connecting it to the duct pipe inlet, viii. Connect the delivery hose of grout pump to the inlet of duct pipe, make sure that there is always enough gout in tank so that air is not sucked into the gout pump, ix. When grout start flowing out of dead end, open the air vent nut of grout cap on both the ends, x. After ensuring that the air is removed, close the other end outlet and duct is filled with gout, xi. Finally close the air vent and operate pump until desired pressure is achieved. 9.12 Launching the Cantilever Form Traveler (CFT) into the new Concreting Position i. After completion of casting and post tensioning of S2 segment, the form traveler is to be moved to new position for next segment casting, ii. To move the form traveler to the new position first rails are moved forward for 5m by taking support from the main frame assembly and secured in new position, iii. De-shuttering of inner form, Outer form and soffit shutter is to be carried out, iv. After making it sure that the shutter is free from concrete, main frame assembly is to be moved forward for 5m by taking support from the rails fixed in new position. 33 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-27 – PT Bar at Rear Truss Location Figure I-28 – PT Bar at Front Truss Location 34 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure II-29 – Side Elevation of CFT a) Main rail launching i. De-stress and Remove all the anchor bars (7) from main rail, ii. Engage the rear undercarriage wheel bracket at the rear and Rail launching wheel bracket at the front, to the top flange of rail, such that the rail hangs from the guide wheels, iii. Using launching jack J3, push the rail forward by one stroke. Repeat the procedure till the rails reach to the final position on next segment. Ensure the rail stopper is engaged at the front and rear end of main rail, iv. Engage the main rail with PT bar anchors (7) in final position, v. During main rail launching make sure that the Rear Tie Down PT Bar number 1 is tensioned and locked properly and front under carriage wheels are not in contact with the rails. 35 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami b) Inner form de-shuttering i. Remove the bottom triangular shutter panels of the Inner Web Form, ii. Open the Inner Form Web Shutter by using turn buckles, iii. Side shift the Inner Web Form by using the ratchet jack, iv. Engage Inner form Launching hangers with anchors (5), v. Disengage and remove the Inner form rear anchor (Casting hanger 4), vi. Disengage the Inner form Front casting hanger (4), vii. Lower down the Inner Form at the Front and Rear simultaneously unless the surface of formwork is clear from the concrete surface, viii. Lower down the inner form by 1000 mm by lowering the PT Bar no.5 connecting launching hangers (5) at the rear and chain tackles of capacity 3MT at the front end, ix. Ensure the inner form over the wheel set is locked with belts to avoid uncontrolled movement in longitudinal direction, x. 3m Launching Beam Extension is to be fixed once we have enough space for installation. c) Outer Web Formwork Opening i. Disengage the PT Bar (13) in the Tie Beam connecting both outer web forms, ii. Move the Tie Beam outward, to allow space for opening of Outer Form, iii. Open Outer Form Web Panels by using Turn Buckles, iv. Remove the Rear/Front Packing Module from Outer Form Web Panels as per the requirement. 36 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami d) Bottom slab de-shuttering i. Engage the outer Chain pulleys of capacity 10MT (2 nos. from front truss and 2nos from rear truss) to the bottom form. Disengage the Outer PT bars (PT bar no.11) connected to bottom form, ii. Distress and remove the rear anchors (PT bar no. 6) engaged during concreting of bottom slab, iii. Disengage the Front Main anchors (6) of Bottom slab from Front hangers engaged during concreting, iv. Lower down the bottom slab using chain pulleys by 50mm to 100mm and ensure bottom slab panel is clear from concrete surface. v. Bottom slab can be further lower down as per requirement after de-shuttering and lowering the Outer form. e) Outer-Form De-shuttering i. Engage Outer form launching hangers, the launching hanger is to be connected by PT Bar no. 10, ii. Disengage and remove the Outer form casting hanger rear PT Bar 3, iii. Engage Chain tackles of capacity 5MT and Disengage the Outer form Front PT bar anchor 3, iv. Lower down the outer form at the front and rear simultaneously unless the surface of formwork is clear from the concrete surface, v. Ensure the surface of outer form is completely free from concrete surface. Side shift the Outer Form Panels by using the transverse hydraulic cylinder (if required), vi. Lower down the outer form by 1000 mm using launching hangers 3 at the rear and chain tackles at the front end. f) Main Frame Launching i. Ensure Inner, outer and bottom formworks are completely free from concrete surface, ii. Activate hydraulic cylinder J2 to de-tension PT Bar anchor 1 (rear tie downs) and transfer the tie-down forces on the Rear under carriage (rear rollers), iii. Lower the traveler onto the rail by releasing the pressure in hydraulic cylinder J1 (main support jacks), 37 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iv. Activate launching jack J3 and advance the form traveler, v. No load or person should be allowed on the working platform during the form traveler launching operation, vi. Once the moving operation is completed, engage the hydraulic cylinder J2, vii. Activate main jack J1 and lift the form traveler. Ensure the front wheels are not in contact with the rail, viii. Activate hydraulic cylinder J2 and align traveler in such a way that the main frame member L4 is horizontal. It can be checked by using spirit level, ix. Insert rear tie down PT Bar anchor 1 and hand tighten. Hydraulic cylinder J2 may now be disengaged. Stitch Segment Casting Above procedure is repeated for casting S3 to S9 segment. After completion of S9 segment two balance cantilever arms from two adjacent piers are connected by a stitch segment (segment S10) of length 3m. The stitch segment will be cast by either of the below two methods. Figure I-30 – Casting of Stitch Segment (A) Stitch segment casting by Hanging shutter arrangement i. During casting of S9 segment 75mm dia. sleeve holes are to be provided in the deck slab and soffit slab of S9 segment as shown in the drawings. These sleeve holes are used to hang the shutter by PT Bars during stitch segment casting, ii. After completion of S9 segment casting and stressing of cable C9, CFT lowering is done, iii. Counter weights of 31.2 MT (concrete blocks) are placed on the opposite side of the pier as well as on the side in which stitch is to be casted. The weight of shutter used for stitch segment casting shall be deducted from the counter weight, 38 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-31 – Sleeve Holes are to be left in the Soffit Slab for Stitch Segment Casting Figure I-32 – Sleeve Holes to be left in Deck Slab for Stitch Segment Casting 39 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-33 – Counter Weight to be provided for Stitch Segment iv. A temporary holding arrangement between the two S9 segments (from opposite directions) shall be provided as shown in drawings, v. This temporary holding arrangement is provided to counteract movement due to the thermal stresses during Stitch segment (S10) casting, Figure I-34 – Side View of Holding Arrangement to counteract the Thermal Stresses 40 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-35 – Sectional view of Holding Arrangement vi. The shutter for stitch segment is fabricated and assembled in three parts. The assembled shutter is positioned exactly below the stitch segment location on the ground, Figure I-36 – Stitch Segment Assembled Shutter vii. These three parts of the cross section are erected with the help of winch and wire rope arrangement one after the other, viii. Two numbers of which are placed on deck slab of already casted S9 segments, wire ropes are passed through the sleeve holes provided for CFT operations and connected to the shutter to be lifted on ground with the help of D-shackles, ix. Both the winch are operated simultaneously and slowly for erection of the shutter, 41 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami x. During lifting of shutter, the area should be barricaded, and no man shall be allowed to enter into the barricaded area. Figure I-37 – Erection of Shutters for the Stitch Segment 42 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-38 – Erection of First Part of Stitch Segment Shutter Figure I-39 – Erection Second Part of Stitch Segment Shutter Figure I-40 – Erection of Third Part of Stitch Segment Shutter 43 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-41 – Shuttering Arrangement for Stitch Segment Casting xi. Complete the shutter alignment and maintain pre-camber levels as per the drawings, xii. All reinforcement cutting and bending are to be done in the cut & bend yard as per approved bar bending schedule and approved drawings and transported to site on trailer, xiii. Reinforcement fixing for stitch segment soffit and web is to be started after completion of bottom form and outer form alignment, xiv. Soffit cable duct profiling is to be done as per the approved design and drawings, xv. After completion of soffit and web reinforcement fixing, duct profiling, the inner form is to be erected, xvi. Complete alignment for inner form and tie the deck slab reinforcement, xvii. Tie rods are to be provided at specified locations to tighten the outer web shutter with inner web shutter, xviii. Concreting is to be started after completion of reinforcement binding and after inspection and approval from AE, xix. Approved concrete mix of grade M50 with specified workability is to be produced in batching plant and transported to Site in transit mixers, xx. Concrete for segments is to be supplied with Concrete pump and pipeline arrangement, xxi. During concrete precautionary measures are to be taken to ensure that no slurry enters into the cable duct pipe, xxii. Cable B8 is to be stressed after concrete attains a strength of 35 MPa, 44 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami xxiii. De-shuttering of inside shutter and outer form is started after concrete attains 70 percent of design strength (i.e., 35MPA). xxiv. Curing of all the exposed surfaces is to be done by water/curing compound for 14 days. xxv. De-shuttering and lowering of stitch segment shutter is to be done in three parts with the help of winch and wire rope arrangement. (B) Stitch segment casting by Cantilever Form Traveler (CFT) i. After completion of S9 segment casting the inner form of CFT is lowered with the help of crane. ii. After completion of inner form lowering CFT is shifted and positioned to the Stitch segment (S10) casting position. iii. The Outer form, Bottom form and inner form of CFT is held in position by the PT Bars at the S9 segment on both the sides. iv. Reinforcement fixing for soffit and the web is to be started after completion of alignment of bottom form and outer form. Figure I-42 – Stitch Segment Casting by using CFT 45 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami v. Soffit cable duct profiling is done as per the approved design and drawings. vi. After completion of soffit and web reinforcement fixing, scaffolding for inner web and deck shutter is erected. The inner form is supported from the casted S9 segments. As shown in the figure. vii. Tie rods are provided at specified locations to tighten the outer web shutter with inner web shutter. viii. Complete the alignment work and start the deck reinforcement tying. ix. Concreting shall be started after inspection and approval from AE. x. Curing of all the exposed surfaces is done by water/curing compound for 14 days. Figure I-43 – Stitch Segment Inner Form 46 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure I-44 – Cut Section for Inner Form of Stitch Segment xi. De-shuttering of inside shutter and outer form is started after concrete attains 70 percent of design strength (35MPA). xii. CFT lowering is started after completion of B8 cable stressing. xiii. CFT bottom form and outer form is lowered by winch and wire rope arrangement. xiv. Above deck components of CFT are lowered by crane. xv. Front truss is lowered first followed by the rear truss lowering in three parts and finally main frames. xvi. Inner form is lowered and dismantled. The dismantled inner form is brought to deck through the opening provided in S6 segment. From deck it is lowered to ground with the help of crane. 47 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.13 Stressing of Soffit Cables i. Stressing of soffit cables is to be started after completion of stitch segment concreting and concrete attains a minimum compressive strength of 35 MPa or 3 days whichever is later for B8 cable. For all other cables stressing shall be done after concrete gains a compressive strength of 50MPa. ii. The threading of soffit cable is done with the help of pushing machine. iii. At the time of reinforcement fixing of deck slab rebar hook/sleeve hole is to be provided at each blister location in the top slab for jack hanging. iv. The sequence of soffit cable stressing to be followed as per the drawings. v. Grouting as described earlier shall be carried out. Figure I-45 – Soffit Cables Key Section Table: Soffit Cable details Sr. No. 1 2 3 4 Segment Cables to be stressed in a segment S3 S5 S7 S9 B7, B8 & B7’ B8’ B5, B6 & B5’ B6’ B3, B4 & B3’ B4’ B1, B2 & B1’ B2’ No. of cables to be stressed in segment 4 4 4 4 48 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Table: Sequence for soffit cable stressing Cable No. Stressing sequence Stressing End B1 B2 B3 B4 B5 B6 B7 B8 After cableB2 After cableB3 After cableB4 After cableB5 After cableB6 After cableB7 After continuity is established After stitch segment is cast From abutment end From abutment end Both Both Both Both Both Both 10. SAFETY PRECAUTIONS AND MEASURES i. Appropriate safety signboards, barriers, delineators and other safeguards are to be provided. ii. All workers, supervisors and engineers deployed in the area should have required safety devices like helmets, safety eye wear, gloves, steel toed shoes, ear plug and fall protective devices etc. iii. Helmet and reflector safety jackets are to be ensured before entering the work area. iv. Working area is to be protected from unauthorized entry. Adequate Lighting arrangement is to be provided at work location. v. If men or vehicles are in dark vicinity, fixed warning lights are to be used to mark the limits of the work. Area lighting and warning are to be used during night-time as needed. vi. No personnel to be allowed inside the working area / swing radius of the equipments. vii. Working area shall be restricted for entry of any unauthorized person. viii. Work methodology of the activity is to be explained to all key personnel and workmen involved in that activity and standing instructions are to be given to all of them. ix. Site first aid facilities are to be made available. x. Good housekeeping is always to be maintained nearby the working area to prevent any kind of hazard. xi. Crane positioning, boom length, radius and permissible capacity to be pre-checked, i.e. Lifting plan is to be developed and accordingly erection activity is to be carried out. 49 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami i. Guide ropes are to be used during all erection work and during the reinforcement shifting work at height. ii. Third party inspection of all lifting tools such as shackles, slings, etc. is to be done. iii. Third party inspection of man basket is to be done. iv. During lifting, no person is to stand within the swinging area of boom. v. Erection sequence is to be explained to all key personnel and workmen involved in that activity. vi. Trailer carrying steel structures is to be located on stable ground where it is to be unloaded prior to removing chains. vii. Use only trained crane operators with certification. viii. Barricade the area covering radius of crane under the load being lifted. ix. Only one person has to give signals and shall ensure that all personnel are out of barricade area. x. Inspect rigging tools and tackles daily. Damaged/defective rigging tools are to be destroyed to prevent their use and those are to be removed from the job site. xi. No structural members are to be left unsecured. No vertical steel member is to be left standing unless secured in a minimum of two directions by horizontal members. xii. All Workers must tie/anchor safety hook of Safety belt. xiii. Ensure that the crane and all rigging materials are identified with their SWL and possess a valid load test certificate. xiv. Experienced signalman is to be appointed for the task. xv. Ensure that lifting points are available on the load, e.g., lifting plates / eye plates. xvi. Keep access ladders that are secured and extended 1.0 meter above the deck is being accessed. xvii. Ensure that structural materials are clamped and secured firmly. xviii. Keep fuel container away from welding area. xix. Keep fire extinguishers nearby to all welding operations, and also additional fire extinguishers should be available. xx. All Workers must tie/anchor safety hook of Safety Belt. 50 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami PART – II Method Statement for Construction of Open Foundation, Piers and Superstructure of Balanced Cantilever Bridge TABLE OF CONTENTS SL. NO. SECTION NAMES 1. 2. 3. 4. 5. 6. 7. 8. 9. SCOPE OF WORK INTRODUCTION RESPONSIBILITY STANDARDS, CODES AND SPECIFICATIONS RECORDS AND DOCUMENTATION MAJOR EQUIPMENTS TO BE DEPLOYED MATERIALS REQUIRED WORK SEQUENCE SAFETY PRECAUTIONS AND MEASURES PAGE NO. 51 52 52 53 53 54 55 56 75 1. SCOPE OF WORK Location Area Name and District Name. Start Chainage (Km) 2634 km+2142.5 m End Chainage (Km) 2635 km+2337.5 m Details: No. of Foundations LHS RHS 13 + 2 = 15 13 + 2 = 15 (Including Abutment) No. of Piers Total = 30 13 (One Pier includes 2 leaf piers) 13 Total = 26 Span Arrangement 10 (98.00 m) 10 (98.00 m) (Balanced Cantilever superstructure) 4 (53.75 m) 4 (53.75 m) Total = 28 Total length (m) 1195 1195 Max. Ht. of Pier (m) 59.935 57.187 Width of Deck Slab (m) 17.50 17.50 51 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 2. INTRODUCTION This Method Statement describes the construction sequence of a Bridge or Viaduct incorporating construction of open Foundation and Pier by Jump formwork, Balanced Cantilever superstructure by Cantilever Form Traveler (CFT) and other finishing works, as per the design and approved drawings for foundation, substructure and superstructure. This method statement describes the methods adopted, required machinery, manpower, material details and applicable standard codes, inspection details along with safety and health matters corresponding to the major activities involved in the construction. 3. RESPONSIBILITY 1. Project in charge shall be responsible for overall completion of Project, as per the technical specifications & design drawings and within time. 2. Planning engineer shall be responsible for ensuring the work is going as per Schedule Scheme & program. 3. Supervisor shall be responsible for managing all equipment, machineries and workmen for all sequential activities. 4. The Project Engineer/Manager shall be responsible for all activities of the work including excavation, installation of reinforcement, RCC and work sequencing. 5. Execution Engineer shall be responsible for various work as per the technical specifications & constriction drawings. 6. QA/QC Engineer shall be responsible for ensuring the quality of work as per specifications. 7. Survey Engineer shall be responsible for ensuring correct alignment and Profile by elevations of structure as per the drawings. 8. Safety Engineer shall be responsible to ensure safety of workers during the progress of work. 52 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 4. STANDARDS, CODES AND SPECIFICATIONS Construction is covered under Specifications for Roads and Bridges (MoRTH) 5th Revision as below (Relevant standards may be followed for construction in different countries): Sl. No. Section Clause 1 200 201, 202 2 300 302, 304 3 1000 1006,1007,1008,1009,1010,1012,1013,1014 4 1500 Formwork 5 1600 Steel Reinforcement 6 1700 Structural concrete 7 1800 Pre-stressing 8 2000 2005-Bearings 9 2100 Open Foundation 10 2200 Substructure 11 2300 Superstructure 12 2500 River Training & Protection Works 13 2600 Expansion Joint 14 2700 Wearing coat and Appurtenances 5. RECORDS AND DOCUMENTATION Sl. No. 1 2 3 4 5 6 Documents Material and Mix design approval Request for Inspection Inspection Check List Approval to Place concrete Concrete Batch Slip Concrete Pour record NOTE: The formats for above mentioned documents should be provided by Quality Department. 53 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 6. MAJOR EQUIPMENTS TO BE DEPLOYED The equipment to be deployed is as below: Sl. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Excavators Breaker Dumpers Dewatering Pump Water Tanker Water Tank Bar Cutting Machine Bar Bending Machine Threading Machine Batching Plant Transit Mixer Concrete Boom Placer Concrete Pump – SP1800 Needle vibrators Pick & Carry Crane Rough Terrain Crane Winch Semi low bed trailer Mini Truck Survey equipment’s Pre-stressing equipment’s Modular Stair tower DOKA Jump Form Form Traveler Bracket staging for Pier Head & adjacent segments Ladders 25 26 54 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 7. MATERIALS REQUIRED (Indian sources and specifications are used) Materials Used Source Cement Ambuja OPC 53 grade, IS 4031 -1988, IS 4032 -1985, Ultra Tech OPC 53 grade IS 12269 - 1987 Water Reinforcement Water from Bhawli Dam M/S SAIL & M/S JSW Coarse Aggregate Stone Crusher Crusher sand Admixture Concrete Compressible Material Specifications As per IS - 2000, IS 3025 As per IS 1786 :2008 As per IS 383-1970, IS 2386 1963 Crushing aggregate excavated from site Crystalline Admixture IS 9103 Corrosion Inhibitor IS 456: 2000 Batching Plant EFNARC Fiber material Figure II-1(A): General Arrangement Drawing of Balanced Cantilever Bridge 55 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure II-1(B) - General Arrangement Drawing of Balanced Cantilever Bridge Figure II-2 - Cross section of Balanced Cantilever Segments 8. WORK SEQUENCE The major works included in the construction of Balanced Cantilever Bridge are as follows: i. Construction of the Access Road, Site Clearing and Grubbing ii. Construction of Open Foundation (As considered in this Article) iii. Construction of Leaf Piers (using DOKA jump form), Construction of Tie Beams iv. Construction of Pedestals to install Bearings and Bearing fixing 56 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami v. Construction of Pier Head segment and adjacent segments (using bracket staging) vi. Construction of Balance Cantilever Superstructure by using Form Traveler (CFT) vii. Construction of Crash Barrier viii. Fixing of Expansion Joints ix. Laying of Wearing Course 8.1 Construction of Access road, Clearing and Grubbing (C & G) viii. Total ROW is to be cleared from debris, bushes or trees along with the roots. ix. Top layer of the excavated soil is to be removed and stacked separately for reuse. x. Layout for movement of vehicles is marked and approach roads are developed. Approach roads are developed using the dozer and excavator. 8.2 Construction of Open Foundation 8.2.1 Survey and Layout The layout area is to be excavated as marked on the surface of the ground as per the drawings. Reference pillars are to be provided for avoiding the level errors. 8.2.2 Excavation for Open foundation i. After removal of top layer of the soil, excavation up to the Founding Level as per approved drawings shall be done using Excavator and Breaker. ii. Excavated soil shall be loaded into the dumpers and then soil shall be dumped in dumping yard. Dumping material shall stacked in the form of stockpiles. iii. Excavated area shall be such that minimum clearance shall be left between finished dimensions of raft and excavation profile, for access to workers and shutter fixing. iv. Excavation slopes shall be as mentioned in approved drawings. v. Ramp shall be made at one end of excavation for access to equipment’s such as excavator, dumpers, crane, etc. 57 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figure re II-3 - Open Foundation (Plan View) Figu igure II-4 - Open Foundation (Elevation) 58 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 8.2.3 Construction of Open Foundation Raft i. After completion of the excavation it is required to prepare the founding level, 100 mm thick PCC of grade M15 shall be laid. ii. PCC shall be transported from Batching Plant to site by using transit mixers. iii. It shall be laid at the excavated level through extended chutes or concrete pump. iv. PCC shall be well compacted and leveled to the foundation level. v. After waiting period of 10 hours, compressible material of required dimension can be placed on the PCC. vi. Reinforcement for the raft shall be cut and bent at the fabrication yard as per approved bar bending schedule. This reinforcement shall be transported to site by trailer. vii. Pick and carry crane shall be used for handling reinforcements. viii. Reinforcement fixing for raft shall be done as per approved drawings. Cover blocks relevant to the grade of concrete for the raft (M40) is to be fixed. ix. After reinforcement fixing and inspection, side shutter shall be fixed. Shutter panels of suitable sizes are to be used. x. Concrete of grade M40 shall be transported from batching plant to site by using transit mixers. xi. After reaching of the transit mixer at site, all necessary concrete tests shall be conducted by Quality Control (QC) Engineer. xii. Concrete shall be poured by using concrete pump. The concrete will progress from the bottom to top. Immersion type vibrators will be used through the gap between reinforcement for adequate compaction. xiii. Curing of concrete is to be achieved by continuous sprinkling of water/wet hessian cloth cover or by using curing compound. Water will be drawn from the water tank located near the site and conveyed to position through pipeline. 59 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami F Figure II-5 - Raft Construction 8.3 Construction of Leaf Piers rs and Tie Beams 8.3.1 Casting of Pier Starter i. After casting the raft, ft, the construction joint shall be prepared at leaff pier p location. ii. Treatment of constru ruction joint shall commence immediately afterr the concrete has partially set within 3 to 4 hours of casting. The laitance shall be removed r by wire brushing. iii. The roughened surfa rface shall be thoroughly cleaned of all loosee materials before placing fresh concrete ete. iv. Reinforcements forr lleaf piers are to be cut and bent in fabricat ation yard as per approved shop drawin ings. This reinforcements are to be transported to site by trailer. v. Pick and carry cranee iis to be used for handling reinforcements. vi. Reinforcement fixingg for pier starter is to be done. vii. Cover blocks of samee grade of concrete as required for the pier (M45 45) is to be fixed. viii. Shutter plates with pr props are to be fixed. The formwork layout iss to t be checked by surveyor. Formworkk jjoints is to be properly inspected. ix. Concrete may be off grade M45 of approved mix design is to bee transported t from batching plant (capaci acity M1 – 60 cum/hr) to site by transit mixers (ca capacity 6 cum). 60 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami x. Concrete Slump checking is to be done at site. xi. Concrete is to be poured inside the shutter mould through concrete pump and adequately compacted by using needle vibrators. xii. Starters for both leaf piers may be cast simultaneously. 8.3.2 Casting of first lift and second lift (considering 3 m height of each lift) i. After concreting of pier starter, construction joint is to be prepared as described earlier. ii. Staging and working platform is to be erected to provide access for workers at required height. iii. Reinforcement fixing for first lift (3m) is to be done and is to be adequately secured and held in position. Reinforcement bars with diameter over 25 mm are to be joined through couplers. iv. Shutter plates with conventional prop system is to be fixed. These shutter plates are to be braced with walers with the help of waler clamps. v. Survey is to be done to check the verticality of formwork. vi. Concrete is to be poured by using concrete pump or boom placer. vii. Adequate compaction is to be done using needle vibrators. viii. After waiting for a period of 24 hours, the shutter plates may be removed. ix. After concreting of first lift, construction joint is to be prepared as described earlier. x. The staging and working platform is to be extended further above for reinforcement fixing. xi. Same procedure as above for reinforcement fixing, shutter fixing, surveying and concreting is to be repeated for second lift (3 m). 61 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figu igure II-6 - Leaf Pier First lift (3m) 8.3.3 Casting of Third Lift (3 m) – Jump Form fixing i. DOKA Shutter Top50 50, Xclimb60 may be used. ii. Reinforcement fixing ng for the third lift is to be done along with fixing ing of cover blocks of M45 grade. iii. Mounting of the botto ttom guiding shoe is to be done. iv. Climbing scaffold iss tto be hanged on the guiding shoe. v. Formwork is to be fix ixed on the climbing scaffold. vi. Bottom Suspended pla platform is to be fixed. vii. Pick and carry crane iis to be used for above purposes. viii. The formwork is to bbe closed and concrete pouring is to be done by boom placer or concrete pump with ppipeline arrangement. ix. Adequate compaction on is to be done by needle vibrators. x. Construction joints is to be prepared. 62 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figu gure II-7 - Leaf Pier Second lift (3m) 8.3.4 Casting of subsequent li lifts (3m each) by Jump Form i. Reinforcement fixingg for the next lift is to be done. ii. After required waiting ing period (24 hours) of earlier lift concreting, the th formwork may be removed. iii. The formwork and the platform are to be cleaned. iv. The top guiding shoee is to be mounted. v. The bottom guiding sh shoe is to be dismounted. vi. The climbing scaffold ld and the formwork is to be hydraulically jumped ped and closed. vii. Survey is to be donee tto check the vertical levels. Any adjustments if required, is to be done. viii. Concrete pouring is to be done by boom placer or concrete pum ump with pipeline arrangement. ix. Adequate compaction on is to be done by needle vibrators. 63 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami x. Construction joints ar are to be prepared. xi. During 4th lift of a pi pier leaf, the casting of adjacent pier leaf can sta tart, due to lack of horizontal clear space ce between adjacent leaf Piers (for example, 2.6m m only). xii. Above procedure is tto be repeated for all lifts till pier top level is reached. r Note: Modular stair tower is to be erected for providing access to workers at required height, during pier construction. Figu igure II-8 - Leaf Pier Third lift (3m) 64 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Leaf Pier Subsequent lifts by Jump Form (3m)) Figure II-9 - Le 8.3.5 Construction of Tie Bea eams i. In addition to the top Tie Beam at pier top, intermediate Tie Beam ams are to be at a vertical spacing of 17 17.5 m. ii. As the Jump formwor ork assembly clears the tie beam location, the cantilever ca brackets are to be fixed. iii. Bottom shutter shalll bbe placed on cantilever brackets. Note that holes les for anchor bolts for fixing cantileverr bbrackets are to be in the leaf piers at required loc ocation. iv. Working platform iss tto be fixed on cantilever brackets. v. Reinforcement fixingg for the Tie Beam is to be done as per approv oved drawings and bar bending schedule. le. vi. Side shutters are to be fixed. vii. Concreting is to be do done by boom placer or concrete pump with pipel eline arrangement. viii. After gaining strengt gth the bottom shutters and the cantilever bra rackets are to be removed. 65 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Pedestals and Bearing fixing 8.4 Construction of Bearing Pe i. Pedestals and bearing ings are to be constructed at P1, P6, P7, P8, P13 13 above the Pier Top. At P1, P6, P8 P8, P13 pier head segments are constructed on o pedestals and bearings. Refer to Fig igures 1(A), 1 (B) and 2, above to understand Pier ier arrangements. ii. There will be no pierr hhead at P7. iii. At other locations, pie pier head segments are homogenous with the leaff piers. p d Segment and Adjacent Segments 8.5 Construction of Pier Head Figure II-10 - Pier H Head (Type 1 – at P2, P3, P4, P5, P9, P10, P11, 1, P12) 66 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figure II-11 11 - Pier Head (Type 2 – at P1, P6, P8, P13) Fi Figure II-12 - No Pier Head at P7 67 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 8.5.1 Casting of Soffit Slab of Pier Head i. Arrangement for erection of bracket staging is to be made at the pier top. Provision for fixing bracket staging is to be made during pier casting. ii. Working platform is to be provided on bracket staging. iii. Soffit shutter and outer side shutter (for webs) are to be fixed in required line and level. iv. Shutter sets is to be hoisted at required height by mobile crane (100 MT) v. Bottom reinforcement of soffit slab and reinforcement of web is to be fixed in position as per drawings. vi. Sheathing ducts for pre-stressing strands are to be placed in position with proper supports as per drawings. Profiling is to be done as per drawings. vii. Top reinforcement of soffit slab is to be fixed in position as per drawings. viii. HDPE pipes are to be inserted inside the sheathing duct and the HDPE pipes are to be kept moving to and fro during concreting to avoid any blockage of sheathing duct. ix. All reinforcements and sheathing ducts are to be provided at required height by mobile crane. x. The concreting of soffit slab is to be done up to bottom junction of soffit & web. xi. Concrete is to be supplied from batching plant to site through transit mixers. xii. Concrete is to be supplied at top by concrete pump with pipeline arrangement supported by adequate staging. 8.5.2 Casting of Webs of Pier Head i. After concreting of soffit slab, balance web reinforcements are to be fixed in position. ii. Sheathing ducts are to be placed in position with proper supports as per drawings. Profiling shall be done as per drawings. iii. Inner web shutter (1st lift height = 3m) is to be placed in position with proper line and levels. Proper props are to be provided to shutter to avoid any bulging of shutter. iv. Concreting for the 1st lift is to be done. v. Compaction is to be done by needle vibrators. vi. Inner web shutter (2nd lift height = 3m) till bottom of deck slab is to be placed in position with proper line and levels. vii. Provisions for fixing the tie rods are to be left at proper location for fixing brackets. viii. Concreting is to be done up to top of web and bottom of deck slab. Inner and outer web shuttering may be removed after 1 day post concreting. 68 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 8.5.3 Casting of deck slab of Pier Head i. After the soffit slab attains sufficient strength, staging and shuttering for deck slab are to be erected over the soffit slab. ii. Brackets are to be fixed to webs and shuttering & staging are to be done for cantilever deck slab. The level and line are to be checked as per drawing. iii. Reinforcement for deck slab is to be fixed in position as per drawing. iv. Sheathing pipes are to be fixed in position as per drawings. v. HDPE pipes are to be inserted inside the sheathing duct and the HDPE pipes are to be kept moving to and fro during concreting to avoid any blockage of sheathing duct. vi. Provisions for fixing Form Traveler parts in position are to be made in deck slab. vii. After checking all levels and lines, concreting is to be done. viii. The deck shutter is to be removed after achieving strength as per drawing. ix. Stressing of cables is to be done after, as specified in drawings. x. Slip checking is to be done after 1 day. xi. After slip checking, cement grouting is to be done in the sheathing duct. Extra cable is to be cut and grout cap is to be fixed. 8.5.4 Casting of Adjacent Cantilever Segments i. Cantilever brackets shall be erected from the leaf piers, as shown in figure below. ii. Similar procedure as described above for soffit slab, web and deck slab casting shall be followed. 69 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figure II-13 - Cantilever Staging for First Spans Casting 8.6 Construction of Balanced C Cantilever Superstructure Balanced cantilever const nstruction implies construction of cantilever segm ments from pier in a balanced manner on eiither side until the mid-span is reached and a stitch s segment is cast there with other hal alf span cantilever constructed from the adjacen ent next pier. The span and segment cross se sections on either side of the pier must be equal in i the design. i. The arrangement madee for casting pier head segment and adjacent segm gments are then to be removed. ii. The form traveler is to be fabricated as per drawings and is to be erec ected over the pier head and adjacent segm ment. iii. Balance cantilever segm gment height varies from 6.0 m at Pier location n to 3.0 m at mid span, as shown in figure ure below. iv. The Form Traveler 2 N Nos. is to be erected on the deck of the pier head he segment and anchored with the deckk slab. Mobile crane is to be used for this purpose se. v. The formwork for castin sting of the segment is suspended from the end of the last segment through Form Traveler. er. The levels and line are to be checked as per the he drawings. vi. The segments are to be cast symmetrically on each side from the pierr head in the same manner as mentioned ab above. 70 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami vii. Concrete is to be suppli plied till pier head using concrete pump and pipel eline arrangement. A booster pump is to bbe placed at pier head which will pump concret rete to the segment using horizontally place ced pipelines. viii. After concreting as per er drawings, each segment is to be symmetrically y post p tensioned. ix. After post tensioning,, slip checking of strands is to be done afterr 1 day of waiting period. x. After slip checking, cem cement grouting is to be done in the sheathing duct. du Extra cables are to be cut and groutt ccaps are to be fixed. xi. After all activities of a segment is completed, the Form Traveler is to be shifted ahead for casting next segmen ent. The Form Traveler rests on top of the earlierr cast c segment. xii. The new segment is to bbe cast, cured and post tensioned as described above. ab xiii. The above sequence iss ffollowed till the Form Traveler reaches the mid id span. xiv. The gap between the tw two half spans cantilevering from two adjacent piers pi is to be filled by casting stitch segmen ent. xv. Stitch segment is to bee ccasted using either of the two Form Travelers. xvi. After casting is complet leted, the Form Traveler is to be dismantled using ing suitable mobile crane (capacity 100 MT T). xvii. Detailed stages of Form rm Traveler operation are described as follows: Figure II-14 - Cross Sectio tion of Balanced Cantilever Segment next to Pier Pie Location 71 Method Stat atement for Construction of Balanced Cantilever Ca Bridge by using C Cast-in-Place Segmental PSC Box-Girde rders along with rreports on Structural Analysis and Des esign, Article by Sandipan Goswami Figure II-15 - Cross Se Section of Balanced Cantilever Segment at Mid id Span Stage-1: Rail beam is fixed on th the deck slab, the Form Traveler is positioned for or casting segment Figure re II-16 - Form Traveler Stage 1 72 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Stage-2: Segment is cast and cables are pre-stressed, the Form Traveler is released, the Rail beams are moved forward (form traveler still in position) Figure II-17 - Form Traveler Stage 2 Stage-3: Form Traveler is moved forward for casting next segment, the Inner soffit formwork is still in-position. Figure II-18 - Form Traveler Stage 3 73 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Stage-4: Inner formwork is moved to be in position and aligned to the required camber. 8.7 Construction of Crash Barrier i. Reinforcement for crash barriers is to be cut and bent at the reinforcement yard and is to be transported to the site by trailer. ii. Reinforcement is to be fixed as per approved drawings along with cover blocks of same grade as that of concrete (M40). iii. After checking of the reinforcement, shutters are to be fixed for crash barrier. Alignment of shutters is to be checked. iv. Concrete of grade M40 is to be produced in the batching plant and transported to the location through transit mixers. v. Concrete is to be poured by using boom placer or concrete pump with pipeline arrangement. vi. Immersion vibrators are to be used for proper compaction of concrete. vii. Removal of shuttering is to be done and curing is to be taken up immediately by water spraying. 8.8 Fixing of Modular type Expansion joint: Modular type Expansion Joints are to be procured as per required technical specifications, and are to be fixed as per accepted Method Statement provided by approved Vendors. 8.9 Laying of wearing coat: Wearing coat is to be 65mm thick by Bituminous Wearing Course comprising of Bituminous Concrete 40 mm thick overlaid with 25 mm thick mastic asphalt, or as per relevant clause of the specification. This work involves the selection of suitable materials, laying of wearing course, texturing and casting of Bituminous wearing coat of specified thickness on the deck slab of the Balanced Cantilever Bridge. The detailed sequence of work is as follows: 8.9.1 Preparation of Base: i. The surface is to be thoroughly swept clean by mechanical broom and all dust is to be removed by blowing compressed air. 74 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami ii. In the location where mechanical broom cannot get access, other approved methods may be used as directed by the Engineer. 8.9.2 Application of Tack Coat i. Single coat of low viscosity bituminous material shall be applied to the surface of deck slab as per relevant clause of the specifications. ii. The surface on which tack coat is to be applied must be clean from dust, dirt and extraneous material. iii. The tack coat is to be applied by a self-propelled or towed bitumen pressure sprayer, properly equipped for spraying the material at a specified rate. iv. The tack coat is to be left to cure until all the volatiles have evaporated before any subsequent construction is started. 8.9.3 Mixing and Transportation of the Mix i. Pre-mixed bituminous materials is to be prepared in a hot mix plant of adequate capacity and capable of yielding a mix of proper and uniform quality with thoroughly coated aggregates. ii. Mixing is to be as per relevant clause of specifications (501.3 of MoRTH). iii. Bituminous materials are to be transported in clean insulated and covered vehicles. 8.9.4 Placing i. Wearing course is to be laid/placed mechanically, as per the approved drawing to avoid segregation and has to cover the specified width of the carriageway. ii. Compaction shall be as per relevant clause of the specifications (501.6 of MoRTH). 8.9.5 Laying Mastic Asphalt i. After placing and compaction of Bituminous Concrete layer, Mastic Asphalt layer of specified thickness (25 mm thick) is to be laid over Bituminous Concrete layer as a finishing coat. 9. SAFETY PRECAUTIONS AND MEASURES i. All heavy excavation equipment must have hooters fitted which would activate during back movement. In addition to above, there would be helpers allotted with such equipment, who shall assist the drivers during back movement. 75 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami ii. Appropriate safety signboards, barriers, delineators and other safeguards is to be provided as required by the nature and location of works. All operations is to be carried out in accordance with safety requirements. iii. All workers, supervisors and engineers deployed in the area should have required safety devices like helmets, safety eye wear, gloves, steel toed shoes, ear plug and fall protective devices etc. iv. The worker must have Helmets and reflector safety jackets, before entering the work area. v. Working area is to be protected from unauthorized entry. Adequate Lighting arrangement is to be provided at work location. vi. If men or vehicles are in dark vicinity, fixed warning lights will be used to mark the limits of the work. Area lighting and warning are to be used during night-time as needed. vii. No personnel should be allowed inside the working area / swing radius of the equipments. viii. Equipment’s working in narrow width is to be well planned. ix. Working area is to be restricted for any unauthorized entry of person. x. Work methodology of the activity is to be explained to all key personnel and workmen involved in that activity and standing instructions is to be given. xi. Site first aid facilities must be made available. xii. Good housekeeping is always to be maintained nearby working area to prevent any kind of hazard. 76 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami PART – III Method Statement for Construction of Hammer Head at the Fixed Pier of Balanced Cantilever Bridge TABLE OF CONTENTS SL. NO. SECTION NAMES PAGE NO. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. SCOPE OF WORK INTRODUCTION RESPONSIBILITY CODES AND SPECIFICATIONS MATERIALS REQUIRED RECORDS AND DOCUMENTATION REFERENCE DOCUMENTS / DRAWINGS MAJOR EQUIPMENTS WORK SEQUENCE SAFETY PRECAUTIONS AND MEASURES 77 78 78 80 81 82 82 84 85 99 1. SCOPE OF WORK Location Start Chainage (Km) End Chainage (Km) Length (m) Balance Cantilever portion Foundation Piers Hammer Heads (at fixed & free piers) Pier caps (at free piers) Spans Extended portion Foundation Piers Abutments Pier caps / Abutment caps Spans Area Name and District Name LHS RHS 2634 km+122.5m 2634km +082.5 m 2635 km+397.5 m 2635 km+377.5 m 1275 m 1295 m Total - 13 13 12 5 10 (98.00 m) 4 (53.75 m) 13 13 12 5 10 (98.00 m) 4 (53.75 m) 26 26 24 10 6 4 2 6 4 (20.00 m) 7 5 2 7 5 (20.00 m) 13 9 4 13 9 28 77 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 2. INTRODUCTION This Method Statement describes the construction sequence of Hammer Head at Fixed Pier of Balanced Cantilever portion of the Balanced Cantilever Bridge. It also describes the methods adopted, equipments, material details and relevant design standards (IS codes), inspection details along with safety and health measures. 3. RESPONSIBILITY 1. Supervisor shall be responsible for managing all equipment, machineries and workmen for all subsidiary activities. 2. Section Engineer/Manager shall be responsible for all activities of the works including reinforcement cutting/bending/fixing, Shutter fixing and concreting works. 3. Execution Engineer shall be responsible for the works as per the technical specifications & drawings. 4. QA/QC Engineer shall be responsible for ensuring the quality of work as per specifications. 5. Survey Engineer shall be responsible for ensuring correct alignment and elevation of structure as per the drawings. 6. Safety Engineer shall be responsible to ensure safety of workers during the progress of work. 7. Planning engineer shall be responsible for ensuring the work is going as per Schedule and planned sequence / methods. 8. Project In charge shall be responsible for overall completion of Project within time. 78 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-1 (A) - General Arrangement Drawing of Balanced Cantilever Bridge (Longitudinal Elevation, Reference Drawing: GAD-01) Figure III-1 (B) - General Arrangement Drawing of Balanced Cantilever Bridge (Longitudinal Elevation, Reference Drawing: GAD-01) Figure III-2 - Cross Section of Balance Cantilever Segments Reference Drawing: GAD-01 79 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 4. CODES AND SPECIFICATIONS Construction of Hammer Head at Fixed Pier of Balanced Cantilever portion of the Balanced Cantilever Bridge is to be as per relevant specifications. However, for cross reference the ‘Specifications for Roads and Bridges (MoRTH) 5th Revision, Govt. of India’ is given as follows: Sr. No. Section 1 1000 Clause Materials for Structures Clause 1006 - Cement, 1007 – Coarse Aggregate, 1008 – Fine Aggregate, 1009 - Steel, 1010 - Water, 1012 – Concrete Admixtures, 1014 – Storage of Materials, 1015 – Tests and Standard of Acceptance 2 1500 Formwork 3 1600 Steel Reinforcement 4 1700 Structural concrete 5 1800 Pre-stressing 6 1900 Structural Steel 7 2300 Superstructure 80 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 5. MATERIALS REQUIRED Materials required for construction of Hammer Head at Fixed Pier of Balanced Cantilever portion of the Balanced Cantilever Bridge is to be as per relevant specifications. However, for cross reference the relevant Indian standards are given as follows: Materials Used Source Specifications Ambuja OPC 53 grade, IS 4031 -1988, IS 4032 -1985, Ultra Tech OPC 53 grade IS 12269 - 1987 Water Water from Bhawli Dam As per IS - 2000, IS 3025 Reinforcement M/S SAIL & M/S JSW As per IS 1786 :2008 Coarse Aggregate Stone Crusher Cement Crusher Sand (Wash Sand) Admixture Concrete Sheathing ducts Anchorages HT Strands Crushing aggregate excavated from site Crystalline Admixture, Corrosion Inhibitor Batching Plant As per IS 383-1970, IS 2386 1963 As per IS 383 IS 9103 IS 456: 2000 EFNARC Morth Specifications Section 1803.2 Morth Specifications Section 1803.3 IS14268 81 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 6. RECORDS AND DOCUMENTATION Sr. No. 1 2 3 4 5 6 Documents Material and Mix design approval Request for Inspection Inspection Check List Approval to Place concrete Concrete Batch Slip Concrete Pour record 7. REFERENCE DOCUMENTS / DRAWINGS The set of editable sample drawings are provided with software ASTRA Pro, which may be downloaded from the company website www.techsoftglobal.com. After downloading the software may be installed in the system. The software provides analysis, design on analysis and sample editable CAD drawings under the section ‘Drawings’. In analysis suite, there are ‘Normal Analysis’, ‘Stage Analysis’ and ‘Dynamic Analysis’, out of these analysis the ‘Normal Analysis’ is mandatory other analyses are optional. The ‘Stage Analysis’ is also known as Non Linear Analysis or P-Delta Analysis or Force Deflection Analysis. The analysis may be carried out for 5-stages each shall be of 20 years. If the design life of the bridge is 100 years then each five stages will give forces and deflections by applying Dead Load, Superimposed Dead Load and Live on the deflected shape of the previous stage. Initially (immediately after construction) if the allowable deflection for a bridge span is ‘Span/1500’ that is to be tested by on-site load test on the bridge. If the deflection is within span/1500 then the load capacity rating capacity is partly alright. Next, upon unloading the bridge span in stages if the deflection recovery is found up to 85%, then the load capacity rating capacity is finally alright. This load test is to be conducted after 20, 40, 60, 80, and 100 years of age of the bridge, if the respective deflections are within the values found by stage analysis then the condition of the bridge is alright at that respective ages, otherwise other tests as NDT may be carried out and decision may be taken whether to go for rehabilitation or replacement of the bridge. The deflection may by deformation in the superstructure, substructure or bearing and that may be observed by reading from sensors attached at strategic locations of the bridge. Next, user has to go to section ‘Design Forces’ in ASTRA Pro and select ‘Normal Analysis’, and then select ‘Design on Analysis’ to get the design results in respect of selected design forces. The sample CAD drawings may be edited as per user’s data and the design. 82 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 8. MAJOR EQUIPMENTS The major equipments to be deployed for Hammer Head construction are as below: Sr. No. Description 1 Pick & carry crane 2 Trailer 3 Crane (min. 150 MT capacity) 4 Concrete pump 5 Transit mixers 6 Curing pump 7 Bar Cutting Machine 8 Bar Bending Machine 9 Welding sets 10 Batching Plant 11 Transit Mixer 12 Diesel Generator 13 Compressor 14 Needle vibrators 16 Pre-stressing jacks 15 Power pack 16 Grout pump 17 Survey equipments 83 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9. WORK SEQUENCE Figure III-3 - Hammer Head at Fixed Pier Hammer Head includes 5 m Pier Head Segment and 5 m S1 Segments on either side. (Total 15 m length x 17.5 m deck slab width) 84 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Hammer Head to be constructed in two stages: Hammer Head Stage 1: Base slab 15m x 7m; Webs and Diaphragm up to 4m height Figure III-4 (A) & (B) - Hammer Head Stage 1 & 2 85 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.1 Working platform for Hammer head support arrangement works xi. Suitable working platform with railings to be fixed at 2 levels – one at corbel level for fixing truss to corbel, and the other 3m above to fix truss top to pier leaf. 9.2 Truss erection i. Truss is fabricated in two parts and shall be supplied to site at erection location by trailer. ii. Two trusses (median side & ROW side) are to be connected with bracings, on ground as per drawings. iii. The two trusses shall be connected with slings and bow shackle to the crane hook. Lifter beam, if required, to be used. iv. Both trusses to be lifted together and placed on corbel by Crane (min. capacity 200 MT). v. Crane positioning, boom length, radius and permissible capacity to be pre decided and accordingly erection activity to be carried out. Figure III-5 - Truss on corbel – Longitudinal (Side) view 86 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-6 - Bracing to Truss vi. Top part of the Truss is to be fixed to Pier leaf with Tie Cone and bolt arrangement. Figure III-7 - Truss erected on Corbel – Transverse view 87 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami vii. Bottom of the Truss is to be bolted to Corbel and grouted with non-shrink mortar. Figure III-8 – CORBEL SECTION Safety precautions during truss erection: a. Crane positioning, boom length, radius and permissible capacity are to be pre checked, i.e., Lifting plan is to be developed and accordingly the erection activity is to be carried out. b. Guide ropes (4 Nos.) are to be used during truss erection works. c. Third party inspection of all lifting tools such as shackles, slings, etc. is to be done. d. Third party inspection of man basket is to be done. e. During lifting, no person shall stand within the swinging area of boom. f. Erection sequence is to be explained to all key personnel and workmen involved in the erection activity. g. Barricade the area covering radius of crane under the load being lifted. h. Only one person to give signals and shall ensure that all personnel are out of barricade area. i. Inspect the rigging tools and tackles daily. Damaged/defective rigging tools are to be destroyed to prevent their use, and are to be removed from the job site. j. No structural members are to be left unsecured. No vertical steel member is to be left standing unless secured in a minimum in two directions by horizontal members. k. All Workers must tie/anchor safety hook of Safety belt. l. Ensure that the crane and all rigging materials are identified with their SWL and possess a valid load test certificate. m. Experienced signalman should be deployed for the task. n. Ensure that lifting points are available on the load. E.g., lifting plates / eye plates. 88 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.3 Erection of Cross Girders with Props i. Total 10 Cross girders (5 pairs with stability bracings) are to be erected. ii. These 5 pairs of cross girders are to be assembled on ground in the required profile as per drawing. iii. Stability bracings are to be provided to each pair of cross girders, as shown in the drawing below. iv. Props with U-head is to be fixed to the Cross girders at designated places. Height adjustment as per required soffit slab profile is to be done through the U-heads. v. Bracings with swivel couplers are to be provided to the props. vi. Crane slings are to be fixed to the cross girder pair. Chain pulley is to be fixed, if required, to maintain the elevation difference between each cross girder. vii. First inner cross girder pair to is be erected, followed by outer cross girders pairs. Bolting is to be done to the truss base plate. viii. Temporary platform by walkway jail or gratings is to be made on erected Cross girders. All safety precautions as mentioned above for truss erection are to be followed. Figure III-9 – Cross girders are erected on Truss 89 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.4 Erection of Runner Beams, Soffit Shutter Panels and Outer Web Shutter Panels i. ii. iii. iv. Runner beams with soffit shutter panels are to be pre-assembled on ground as per drawings. Support members are to be provided below the runner beams or lifting the assembly together. Crane slings are to be connected to the support members and the assembly is to be lifted and placed on the U-head jacks. Orientation and top level of shutter panels are to be checked. Any corrections, if required, are to be done through adjustments in U-head jacks. Figure III-10 – Runner Beams and Soffit Shutter Panels v. Outer Web Shutters up to 4 m height are to be pre-assembled on ground by connecting required walers as per drawing. This assembly is to be made of 5m parts each. vi. This 5m assembly of Outer Web Shutter is to be attached to the crane slings at waler location and lifted and placed on the Soffit Shutter. Required connection to soffit shutter and Alignment props are to be provided. vii. Application of shuttering oil is to be done. viii. Survey checking is to be done to adjust the correct profile of outer Web shutters. 90 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-11 – Outer Web shutter with Alignment props 9.5 Reinforcement fixing, Shutter fixing, Concreting, De-shuttering i. All reinforcement cutting and bending are to be done in the cut & bend yard, as per approved bar bending schedule and approved drawings. ii. Cut & bent steel are to be transported to the fixing location by trailer. iii. Reinforcements are to be lifted and supplied on the soffit shutter panels by crane. The reinforcements are to be adequately tied in bundles and guide ropes are to be used during hoisting. All safety precautions as mentioned in above sections are to be followed. iv. Reinforcement for Soffit slab, Web and Diaphragm (up to 4m height) are to be done. v. Adequate staging arrangements are to be provided for worker access. vi. Concreting of Hammer head Stage 1 is to be done in 2 pours: Pour 1: Bottom slab + 600 mm height of Webs & Diaphragm Pour 2: Balance Web & Diaphragm up to a total height of 4m (including pour 1) 91 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-12 – Hammer Head Stage 1 – Pour 1 & Pour 2 vii. Accordingly, inside Web and Diaphragm shutter till 600 mm height above soffit slab is to be done. viii. Stopper / end shutters for Soffit slab and Webs are to be fixed. ix. Temporary platform arrangement is to be done to pour concrete. x. Concrete M50 is to be mixed in batching plant and transported to Site via transit mixers. xi. Concrete is to be supplied to Hammer head with Concrete pump and pipeline arrangement. xii. During pouring, adequate compaction is to be done by Needle Vibrators. xiii. After waiting period of 24 hours, balance inner shutter of Web and Diaphragm up to total height of 4 m is to be fixed with alignment props, waler & tie rod arrangement. xiv. Concreting of Stage 1 Pour 2 is to be done. 92 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-13 – Shutter arrangement for Stage 1 – Pour 1 & Pour 2 Figure III-14 – Hammer Head Stage 1 Isometric view 93 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami xv. After 24 hours of concreting, the inner and outer side shutters of Webs and Diaphragm are to be removed. xvi. Curing of exposed surfaces is to be done by water or curing compound for 14 days. xvii. After 35 MPa or 70% of design strength is achieved, the bottom Soffit Shutter Panels with Runner Beams can be removed. First, the U-heads are to be lowered. Then the crane has to pull out the runner beams and shutter panels and lower it on ground. xviii. Subsequently, the Cross girders are to be removed. Lifter beam is to be used for this purpose, as shown below. Figure III-15 – Cross girder removal arrangement xix. After removal of all cross girders, the truss bracing is to be removed. Then, both the trusses are to be lowered by crane individually. 94 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Hammer Head - Stage 2: Balance height of Webs and Diaphragm, and Deck Slab (15m x 17.5m) with Ribs Figure III-16 – Hammer Head - Stage 2 Support arrangement – Transverse view Figure III-17 – Hammer Head - Stage 2 Support Arrangement – Longitudinal view 95 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.6 Erection of Stage 2 brackets i. There are total 12 Nos. of Stage 2 brackets i.e. 6 pairs. Each pair is to be assembled on ground by fixing bracings as per drawing. ii. After Stage 1, as the Webs gain strength of 35 MPa or 70% of design strength, the Stage 2 brackets are to be lifted by Crane and are to be fixed to the Webs. iii. Temporary working platform with necessary safety arrangements is to be fixed outside the Web, for workers’ access during Stage 2 brackets. iv. 4 pairs of brackets are to be erected from one position of crane along the longitudinal axis. Balance 2 pairs of brackets are to be erected from the opposite position of the crane along the longitudinal axis. v. The bracket top is to be fixed with Macalloy bars 32 mm dia. The bracket bottom is to be fixed with M39 bolts as per the drawing. vi. After bracket erection, fixing of Tie member between opposite brackets is to be done. vii. Stressing of Macalloy bars is to be done by Stressing jacks. Macalloy bar is to be stressed as per the drawings. viii. Temporary platform is to be made above the brackets. ix. All safety precautions as described in above sections are to be followed for all erection activities. Figure III-18 – Stage 2 Brackets fixing to Webs 96 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9.7 Fixing of balance reinforcement of Web and Diaphragm i. All reinforcement cutting and bending are to be done in the cut and bend yard, as per approved bar bending schedule and approved drawings. ii. Cut and bent steel are to be transported to the fixing location by trailer. iii. Reinforcements are to be lifted and supplied to the top by crane. The reinforcements are to be adequately tied in bundles and guide ropes are to be used during hoisting. All safety precautions as mentioned in above sections are to be followed. iv. Fixing of balance web and diaphragm reinforcement is to be done as per approved drawings. v. Fixing of HDPE ducts at web location is to be done as per approved drawings. 9.8 Fixing of Beams over bracket, Trestle supports, Runner beams and Shutter panels (Web, Diaphragm, Deck slab), Fixing of balance reinforcement of Stage 2 i. ii. iii. iv. v. Beam over bracket (ISMC125 b/b) with trestle supports, runner beams, shutter panels is to be assembled on ground in 5 m components (3 units in ROW side on brackets, 3 units in Median side on brackets, 3 units inside box on Tie member / Soffit slab). Figure III-19 – Fixing of balance reinforcement of Stage 2 These units are to be provided with support members / lifters for lifting by Crane. All safety precautions as mentioned above are to be followed during erection. After erection on brackets, survey checking is to be done for maintaining the required longitudinal and transverse slope as per the drawing. Any correction in alignment is to be done by adjusting the U-heads. 97 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami vi. All web and diaphragm shutter panels are to be aligned by tie rod fixing through walers. vii. Fixing the bottom reinforcement of deck slab including Ribs is to be done. viii. After reinforcement fixing of Ribs, the Rib Side Shutter is to be fixed by tie rods through walers. ix. After fixing of deck slab bottom reinforcement, the fixing of HDPE ducts in deck slab is to be done. Profiling is to be done as per drawings. x. Plain HDPE pipe is to be inserted inside the sheathing duct and the HDPE pipe is to be kept moving to and fro during concreting to avoid any blockage of sheathing duct. xi. Fixing of anchorage including bursting reinforcement is to to be done. xii. Fixing of top reinforcement of deck slab and crash barrier reinforcement are to be done. xiii. Fixing of side shutter of deck slab is to be done as per approved drawings. xiv. Fixing stopper shutter for balance web and top deck slab is to be done as per approved drawings. xv. Fixing of inserts and sleeves for Form Traveler are to be done, as per drawings of Form Traveler. 9.9 Concreting Stage 2 and Stressing i. Concreting of Balance Web and Diaphragm and Deck Slab is to be done. ii. Concrete M50 is to be mixed in the batching plant and transported to the site via transit mixers. iii. Concrete is to be supplied to Hammer Head with concrete pump-pipeline arrangement. iv. During pouring, adequate compaction is to be done by Needle Vibrators. 9.10 Dismantling of Stage 2 support arrangements i. After 24 hours of concreting, side shutters of webs and diaphragm may be removed. ii. After gain of strength of 35 MPa or 70% of design strength, the deck bottom shutter panels can be removed. iii. A C-frame with Crane is to be used for removing the cantilever bottom deck panels, after lowering the U-heads. iv. The trestle supports and beams over brackets are to be removed by crane. v. After removing Tie members, a C-frame with Crane is to be used to remove the Stage 2 brackets. vi. Curing of exposed surfaces to be done by water or Curing compound for 14 days. 98 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure III-20 – Stage 2 Bracket dismantling using C-frame 9.11 STRESSING After gain of strength of 35 MPa or 70% of design strength, stressing of cables is to be done, as per approved pre-stressing drawings. 10 SAFETY PRECAUTIONS AND MEASURES: i. Appropriate safety signboards, barriers, delineators and other safeguards are to be provided. ii. All workers, supervisors and engineers deployed in the area should have required safety devices like helmets, safety eye wear, gloves, steel toed shoes, ear plug and fall protective devices etc. iii. Helmet and reflector safety jackets are to be ensured before entering the work area. iv. Working area is to be protected from unauthorized entry. Adequate Lighting arrangement is to be provided at work location. v. If men or vehicles are in the dark vicinity, fixed warning lights are to be used to mark the limits of the work. Area lighting and warning are to be used during night-time as needed. vi. No personnel is to be allowed inside the working area / swing radius of the equipments. 99 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami vii. Working area is to be restricted for any unauthorized entry of person. viii. Work methodology of the activity is to be explained to all key personnel and workmen involved in that activity and standing instructions is to be given. ix. Site first aid facilities are to be made available. x. Good housekeeping is always to be maintained nearby working area to prevent any kind of hazard. xi. Crane positioning, boom length, radius and permissible capacity are to be pre-checked, i.e. Lifting plan to be developed and accordingly erection activity is to be carried out. xii. Guide ropes is to be used during all erection works and during reinforcement shifting works at height. xiii. Third party inspection of all lifting tools such as shackles, slings, etc. is to be done. xiv. Third party inspection of man basket is to be done. xv. During lifting, no person is to be allowed to stand within the swinging area of boom. xvi. Erection sequence is to be explained to all key personnel and workmen involved in that activity. xvii. Trailer carrying steel structures is to be located on stable ground where it is to be unloaded prior to removing chains. xviii. Only trained crane operators with certification are to be deployed. xix. Barricade the area covering radius of crane under the load being lifted. xx. Only one person to give signals and has to ensure that all personnel are out of the barricade area. xxi. Inspect rigging tools and tackles daily. Damaged/defective rigging tools to be destroyed to prevent their use, and removed those from the job site. xxii. No structural members are to be left unsecured. No vertical steel member is to be left standing unless secured in a minimum of two directions by horizontal members. xxiii. All Workers must tie/anchor safety hook of Safety belt. xxiv. Ensure that the crane and all rigging materials are identified with their SWL and possess a valid load test certificate. xxv. Experienced signalman should be appointed for the task. xxvi. Ensure that lifting points are available on the load. e.g., lifting plates / eye plates. xxvii. Keep access ladders that are secured and extended 1.0 meter above the deck being accessed. 100 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami xxviii. Ensure that structural materials are clamped and secured firmly. xxix. Keep fuel container out of away from welding area. xxx. Keep fire extinguishers nearby to all welding operations, as well additional fire extinguishers should be available as stand by. xxxi. All Workers must tie/anchor safety hook of Safety belt. 101 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami PART – IV Method Statement for Construction of Tack Coat and Bituminous Concrete for Balanced Cantilever Bridge TABLE OF CONTENTS SL. NO. SECTION NAMES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. SCOPE OF WORK INTRODUCTION RESPONSIBILITY CODES AND SPECIFICATIONS MATERIALS REQUIRED RECORDS AND DOCUMENTATION REFERENCE DOCUMENTS / DRAWINGS MAJOR EQUIPMENTS CONSTRUCTION SEQUENCE SAFETY PRECAUTIONS PAGE NO. 103 103 104 105 105 106 106 106 107 110 102 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 1. SCOPE OF WORK All the requirements are to be set out for Construction of Bituminous Concrete to meet all the contract requirements of the Specifications for work operation, safety, quality and environmental compliance. 2. INTRODUCTION This Method Statement describes the construction of Bituminous Concrete. It also describes the methods adopted, equipment’s, material details and relevant IS codes, inspection details and safety and health measures. Figure IV-1 – Typical Cross Section (TCS-A) 103 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Figure IV-2 – Typical Cross Section (TCS-B) RESPONSIBILITY 3. i. Section in-charge shall report to the PIC, being responsible for overall implementation and control of construction activities and shall also be responsible for overall monitoring and control of manpower, materials, transportation facilities etc. ii. Site Engineers/Site foremen shall report to section in-charge and shall be responsible for execution of works according to specifications and drawings, ensuring safety at work site. iii. QA/QC Engineer shall report site QA/QC in-charge and shall be responsible for overall control and inspection of QC activities as per approved QAP at site during erection work. 104 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami iv. Planning and Monitoring Engineer shall be responsible for arrangements of adequate resources in time for works and proper planning to utilize resources in prudent manner for completing activities without loss of time. v. Safety Officer shall ensure that safety procedures are followed at site. CODES AND SPECIFICATIONS 4. Relevant specifications are to be followed. In India MORT&H, Rev. 5, specifications clause No: 503 & 507 and technical specification of contract. MATERIALS REQUIRED 5. i. Tack Coat Binder: The binder used for tack coat shall be either Cationic bitumen emulsion (RS 1) complying with IS:8887 or suitable low viscosity paving bitumen of VG 10 grade conforming to IS:73.The type and grade of binder for tack coat shall be as specified in the contract or as directed by the Engineer. ii. Bitumen: The bitumen shall be viscosity graded paving bitumen complying with IS:73 or as specified in the contract. iii. Coarse Aggregate: The Coarse aggregate shall consist of crushed rock, crushed gravel or other hard material retained on 2.36 mm sieve. It shall be clean, hard, durable & cubical shape, free from dust, soft organic and deleterious substances. iv. Fine Aggregate: The Fine aggregate shall consist of crushed or naturally occurring mineral material, or a combination of two, passing 2.36 mm sieve and retained on 75micron sieve. It shall be clean, hard, durable & cubical shape, free from dust, soft organic and deleterious substances. v. Filler: Filler shall consist of finely divided mineral matter such as rock dust, hydrated lime or cement approved by the Engineer. 105 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 6. RECORDS AND DOCUMENTATION i. ii. iii. iv. v. vi. vii. 7. Good for construction drawings Technical specifications Relevant applicable Specification and Codes (For India MORTH & IS & IRC codes) Level sheet of BC Top Approved Mix Design Laying records Lab test records REFERENCE DRAWINGS TCS Drawings (Given above) Figure IV-1 – Typical Cross Section (TCS-A) Figure IV-2 – Typical Cross Section (TCS-B) General Arrangement Drawings: GAD 1 to 3 of Software ASTRA Pro Drawings 8. MAJOR EQUIPMENTS The major equipment’s to be deployed for Tack coat & Bituminous concrete construction are as below: Sl. No. 1 2 3 4 5 6 7 8 9 10 11 Equipment Description Mechanical broom with tractor Bitumen sprayer Hot mix plant (160 TPH) Front end loader Tandem Rollers Pneumatic tyred rollers Tippers Asphalt paver Survey equipment’s Air compressors Laboratory equipment’s 106 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami 9. CONSTRUCTION SEQUENCE Setting out: The limits of work will be surveyed and marked as per the approved cross sections using survey instruments and lime powder etc. Preparation of base: The surface on which the bituminous concrete is to be laid shall be prepared in accordance with cl. 501 & 902 as appropriate or as directed by the Engineer. The surface shall be thoroughly swept clean by mechanical broom or air jet and dust removed by compressed air, Joints, dowel and tie bars. Application of tack coat: The application of tack coat shall be at the rate specified in the table 500-5, and it shall be applied uniformly. The normal range of spraying temperature for a bituminous emulsion shall be 20°C to 70°C. Type of surfaces Bituminous surfaces Granular surfaces treated with primer Cement concrete pavement Rate of spray of binder in Kg per sq. m. 0.20-0.30 0.25-0.30 0.30-0.35 Curing of tack coat: The tack coat shall be left to cure until all the volatiles have evaporated before any subsequent construction is started. No plant or vehicles shall be allowed on the tack coat other than those essential for the construction. Selections and approval of BC material: BC material will meet the requirements of specifications as per cl. 507.2 and shall be satisfaction by the Engineer. The Job Mix Formula (JMF) will be prepared well in advance of planned works and its suitability will be verified by laying trail stretches as per the MORTH specifications. The joint test reports shall be forwarded for Engineer’s approval. 107 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Laying Trials: The contractor shall carry out laying trials, to demonstrate that the proposed mix can be successfully laid and compacted all in accordance with clause 501. The laying shall be carried out on a suitable area which is not a form of the works. The area of laying trial shall be minimum 100 sq. m of construction similar to that of road works, and it shall be in all respects, particularly compaction, the same as the project construction, on which the bituminous material is to be laid. The compacted layers of BC shall have a minimum field density equal to or more than 92% of the average theoretical maximum specific gravity obtained on the day of compaction in accordance with ASTM D2041. Mixing and Transportation of BC Materials: The pre-mixed bituminous materials shall be prepared in a hot mix plant of adequate capacity and capable of yielding a mix of proper and uniform quality. Approximate mixing temperature are given in the table 500-2 of MORTH. Bituminous materials shall be transported in clean insulated and covered vehicles. The hot mix plant shall be calibrated to regulate and measure the flow of fed materials in quantities required as per approved mix proportions and targeted discharge capacity. For example the table is given as per Indian Standard and Specifications: Table 500-2 of MORTH: Mixing, Laying & Rolling temperature for Bituminous mixes (Degree Celsius) Bitumen Bitumen viscosity temperature grade Aggregate temperature Mixed material temperature Laying temperature (Minimum) VG-40 160-170 160-175 160-170 150 VG-30 VG-20 VG-10 150-165 145-165 140-160 150-170 145-170 140-165 150-165 145-165 140-160 140 135 130 Rolling temperature (Minimum) 100 90 85 80 *Rolling must be completed before the mat cools to these minimum temperatures. Spreading/Paving the Bituminous Material: As soon as possible after arrival at site, the material shall be supplied continuously to the paver and laid without delay. The temperature of mix at the time of laying shall be as per table 500-2 of MORTH. Except in the areas where paver cannot get access, bituminous material shall be spread, leveled and tamped by self-propelled paving machine equipped with an electronic sensing device. 108 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Control of Alignment, Level and Surface Regularity: The levels will be controlled during the paving by the dip checker and surveyor by using dipstick and level instrument in addition to sensor of the paver. The rake men under the direction of surveyor and competent supervisor will rectify any variation from the targeted levels and the horizontal alignment immediately. The horizontal alignment will be within +/- 10mm with respectto center line and the surface levels shall be within +/- 6mm. The maximum allowable difference between road surface and underside of 3 m straight edge when placed parallel with, or at right angle to the center line of the road at points decided by Engineer shall be 3 mm. Compaction and Quality Control: Bituminous material shall be laid and compacted in layers, which enables the specified thickness, surface levels, regularity requirements and compaction to be achieved. Compaction of bituminous material shall commence as soon as possible after laying. Roller shall move at a speed of not more than 5 Kmph. Compaction shall be completed before the temperature falls below the minimum rolling temperature mentioned in the table 500-2 of MORTH. The initial or breakdown rolling will commence at a minimum temperature of 120°C. and be done with 8-10 tonne static weight smooth-wheel roller. The intermediate rolling shall be done with 8-10 tonne static weight or vibratory roller or with pneumatic tyred roller of 1215 tonne with a tyre pressure of at least 0.56 Mpa. The finishing rolling shall be done with 6-8 tonne smooth wheeled tandem rollers. The relevant quality assurance will be built up as per the Quality Assurance Plan (QAP) for the concerned item. All joints where required, will be cut vertically to the full thickness of the previously laid mix. All loosened material shall be discarded, and the vertical face will be coated with a suitable viscosity grade hot bitumen or cold applied emulsified bitumen. The density of finished layers shall be determined by taking 150mm diameter cores. The density of finished paving layer shall not be less than 92% of the average theoretical maximum specific gravity of loose mix (Gmm) obtained on the day of compaction in accordance with ASTM D2041. Request for inspection and approval: Once the stretch is ready with respect to surface level and compaction, Engineer's representative will be requested through an RFI (Request for inspection) for verification and approval of the same. The joint level and core density tests shall be conducted as per the frequency. After the approval of the said stretch is obtained, the next stage of construction will proceed. Arrangement of traffic and safety during construction: Construction shall he carried out in a safe manner creating least interference possible to the flow of traffic. In case construction is to he carried out after diverting the traffic on a temporary diversion, prior approval of the arrangements at diversion shall be taken. 109 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami If construction is to be carried out very near to the plying traffic necessary barricades, regulatory/ informatory/warning signs, flags, markers (white painted gunny bags/ stones) shall be provided. Erected and maintained during the construction. Safety is maintained as per the safety manual that is already submitted. Risks Involved: i. ii. iii. 10. Collision of vehicles while moving on the site and on existing road adjacent to the site Spillage of material on the existing road while transporting Burn injury, inhalation of fume from hot bitumen. SAFETY PRECAUTIONS i. Appropriate safety signboards, barriers, delineators and other safeguards shall be provided as required by the nature and location of works. All operations will be carried out in accordance with safety requirements. ii. All the staff and workers shall be provided with personal protective equipment like safety helmets, safety hand gloves, safety shoes, safety goggles, retro reflective jackets, dust masks as per the requirement. iii. Lighting adequate shall be provided in the working zone during night times iv. All equipment’s/vehicles will be fitted with back horns and lightening if required with a signal man. v. The hauling path is specified for better movement of vehicles and to reduce collision. vi. Unauthorized persons and visitors shall not be allowed within the working areas. vii. Vehicles tracks shall be kept moist to prevent flying of dust particles with the vehicular movement. viii. SMOKING is strictly prohibited in working area. ix. Dry Chemical Powder (DCP) fire extinguisher shall be ensured during the activity. 110 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami References: 1. The Academic Text Book Title: Computer Aided Bridge Engineering, Pages: 381, Publisher: Nova Science Publishers, New York, USA, ISBN: 978-1-68507-413-5, Publisher, for Book, Software and Tutorial videos, Web page: https://novapublishers.com/shop/computer-aided-bridge-engineering-detail-designof-pre-stressed-concrete-i-girder-box-girder-bridges/ Contact: Ms. Lisa Gambino, Email: marketing@novapublishers.com Amazon.com, https://www.amazon.com/Computer-Bridge-Engineering-SandipanGoswami/dp/1685074138/ref=sr_1_1?crid=OSLTNH01MZ5M&keywords=computer+aided+brid ge+engineering+sandipan+goswami&qid=1677561808&sprefix=computer+aided+bridge+engine ering+sandipan+goswam%2Caps%2C380&sr=8-1 Amazon.in, https://www.amazon.in/Computer-Engineering-Pre-Stressed-Concrete-BoxGirder/dp/1685074138/ref=sr_1_1?crid=1KKU7ABGE8BNJ&keywords=computer+aided+bridge+ engineering+sandipan+goswami&qid=1677561678&sprefix=computer+aided+bridge+engineerin g+sandipan+goswami%2Caps%2C265&sr=8-1 Software used in the book: ASTRA Pro (Standard used AASHTO LRFD, Eurocode2, IRC 112, IRC 6) Download from website: www.techsoftglobal.com, Email: techsoftinfra@gmail.com Software ‘ASTRA Pro Premium’ is for the Analysis Design and Drawings of Bridges and Structures. To master the concept of Modeling, Analysis and Design of a Balanced-Cantilever Bridge the default sample design data may be processed by downloading the software ‘ASTRA Pro Premium’ from website www.techsoftglobal.com. ‘ASTRA Pro – Premium’ software provides a set of (100+) Sample Editable CAD Drawings for construction of Balanced Cantilever Bridge. 2. The Academic Text Book Title:: Computer Aided Highway Engineering, Pages: 518, Publisher: Taylor and Francis, CRC Press, Routeledge. Boca Raton, Florida, USA, ISBN: 978-0-367-49338-7, Webpage: https://www.taylorfrancis.com/books/mono/10.1201/9781003045830/computeraided-highway-engineering-sandipan-goswami-pradip-sarkar 111 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Contact: Dr. Gagandeep Singh, Chief Editor, Phone: +91 96460 26201, Email: Gagandeep.Singh@taylorandfrancis.com, North and South America: orders@taylorandfrancis.com, Australia and New Zealand: books@tandf.com.au, UK, Europe and rest of world: cis@tandf.co.uk, Amazon.com, https://www.amazon.com/Computer-Aided-Highway-Engineering-Sandipan-Goswamiebook/dp/B0933MCSLH/ref=sr_1_2?crid=1PGHL4WRD6ZLE&keywords=engineering+books+by+ sandipan+goswami&qid=1677822338&sprefix=%2Caps%2C1756&sr=8-2 Software used: HEADS Pro (Standard used, AASHTO, IRC) Download from website: www.techsoftglobal.com, Email: techsoftinfra@gmail.com Tutorial videos: https://www.youtube.com/channel/UCLY751jDWngqMfhKrlRcVwA/playlists Tutorials Website: www.roadbridgedesign.com, Select menu item: “Book Tutorials”, Select “Computer Aided Highway Engineering” and download each time with data and guide for practice. Download Trial Version of Software “HEADS Pro”: Website: www.techsoftglobal.com, 3. The Academic Text Book Title: Pavement Engineering – Design, Construction and Maintenance, Pages: 344, Publisher: PHI Learning (Formerly, Prentice-Hall), New Delhi, India, ISBN: 9789391818104, Web page: https://www.phindia.com/Books/BookDetail/9789391818104/pavement-engineering-goswami Contact: Ms. Lakshmi, Phone: +91 11 4303 1127 (IST 10:00am to 05:00pm, Monday to Friday), Email: lakshmi@phindia.com and malaya@phindia.com Amazon.com, https://www.amazon.com/PAVEMENT-ENGINEERING-DESIGN-CONSTRUCTION-MAINTENANCEebook/dp/B0BVVDFFNP/ref=sr_1_3?crid=1PGHL4WRD6ZLE&keywords=engineering+books+by+ sandipan+goswami&qid=1677822534&sprefix=%2Caps%2C1756&sr=8-3 Amazon.in, https://www.amazon.in/Pavement-Engineering-Design-ConstructionMaintenance/dp/9391818102 112 Method Statement for Construction of Balanced Cantilever Bridge by using Cast-in-Place Segmental PSC Box-Girders along with reports on Structural Analysis and Design, Article by Sandipan Goswami Software used: HEADS Pro (Standard used, AASHTO, IRC) Software download from website: www.techsoftglobal.com, Company Email: techsoftinfra@gmail.com 4. The recent book “Road Safety by Traffic Management and Transportation Engineering with Intelligent Transport System, Green Highways” is of about 500 pages. 113 Design Report on Normal Analysis (Multi-cell ACI-AASHTO) The Structural Design Reports are obtained from software ASTRA Pro Readers/Users may download software ASTRA Pro from the website as given below and install in the PC/Laptop with Windows 10/11. Next, Open ‘ASTRA Pro Release 24’ by clicking on the desktop icon, next, by selecting menu items ‘File’, then ‘Bridge Design’, then Balanced Cantilever Bridge, Process default sample data as provided for analysis and design. In Licensed version of ASTRA Pro users may change the default sample values. Before processing the analysis and design users are suggested to open the set of sample editable CAD drawings as provided with ‘GAD’ and ‘Super Structure’. The drawings can be edited either in ASTRA Viewer or AutoCAD as desired and saved in DWG or DXF formats. Website: www.techsoftglobal.com Various Tutorial Videos are being continuously uploaded in channel ‘Techsoft Forum’ in YouTube. Design Report on Normal Analysis (Multi-cell ACI-AASHTO) ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * By ACI/AASHTO * * * * DESIGN ON ANALYSIS RESULTS * * Date 03.08.2023 AT 15:17:17 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Website: www.techsoftglobal.com Multi-Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * By ACI/AASHTO * * * * DESIGN ON ANALYSIS RESULTS * * Date 03.08.2023 AT 15:17:17 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 328ft Bridge Width = Wbridge = 57.42ft Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15' Slab thickness = t = 6 inch, Wearing Surface Uniformly Distributed Load = w2 = 30 psf, n = 9 bb = 1 Clear Cover = cc = 1.5 inch Unit weight of Concrete = w = 150 pcf (pound per Cu. Ft) Loads: Live Load = 0' Wearing Surface = Lw = 30 psf Material Properties: fc = 7.25 ksi fs = 72.5 ksi For Shear Design: Stirrups Legs = 2 Provide Bar# = 5 Spacing = 7 Number of stirrups per segment = 20 NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Gridres. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the ‘Hammer Head’ and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using ‘Cantilever Form Traveler’ or CFT. (Analysis and design have considered sections From support to ‘D’, ‘D’ to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 57.42 ft Number of girders = N = 6 Width of each girder = b = 15 inch. Clear span between girders = S = [B - (Nxb/12)/(N-1)] = [(57.42 – (6x6/12)/(5] = 9.984 The c/c distance between girders = GC = c + b/12 = 9.984 + 15/12 = 11.234 ft. Unit weight of Concrete = w = 150 pcf (pound per Cu. Ft) Slab thickness = t = 6 inch, Slab Uniformly Distributed Load = w1 = (t/12) x w = (6/12) x 6 = 75 psf = 0.075 ksf Wearing Surface Uniformly Distributed Load = w2 = 30 psf, Total UDL = wDL = w1 + w2 = 75+30 =105 psf = 105/1000 ksf = 0.105 ksf Dead-load moment = MDL = wDL x S^2/10 = 0.105 x 9.984^2/.10 = 1.047 k-inch/ft AASHTO specifies Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(9.984+2)/32] x 16 = 4.7936 k ft/ft ft. Impact factor = I = 50/(S+125) = 0.370 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = 4.7936 x 0.3 = 1.438 k-ft/ft Total moment = MT = MDL + MLL + MIMP = (1.047 + 4.7936 + 1.43808) = 7.278 k-ft/ft For design = fc’ = 7.25 ksi (27.5 MPa) fc = 0.4 x fc’ = 0.4 x 7.25 = 2.9 ksi n = 9 k = n/(n+20/1.2) = 9/(9+20/2.900) = 0.783, j = 1– k/3 = 1 – 0.783/3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (2.9 x 0.783 x 0.739) = 0.839 ksi bb = 1 d req = √(MT/R/bb) = √(7.278 / 0.839 / 1) = 2.946 inch Clear Cover = cc = 1.5 inch d = (t – cc) = 6”–1.5” = 4.5 inch If (d < dreq) d = dreq d =4.5 inch Slab thickness = d + cc = 4.5 + 1.5 = 6 inch. For design = fs = 72.5 ksi Required reinforcement, As = MT x 12/ (fs x j x d) = 7.278 x 12 / (72.5 x 0.739 x 4.5) = 0.362 in2/ ft Use #5 or #6 @required spacing for inch centre to centre, to fulfill the above reinforcement reqt.) (For example: Use #5 @ 7 inch c/c or #6 @10 inch c/c) Provide Bar# 5, Area = 0.31, Spacing 7 inch c/c, As’ = 0.310 x 2.00 = 0.62 in2 Also, 2.2/ √S = 2.2/√9.984 = 0.696 > 0.67 Distribution steel, As-dist = 0.620 x As = 0.620 x 0.362 = 0.225 in2/ ft As(dist) per c/c span = GC x As = 11.234 x 0.225 in2/ ft = 2.523 in2 Use #7 @required spacing for inch centre to centre, to fulfill the above reinforcement reqt.) (For example: Use 7 nos. # 5 inch bars, to be placed within the clear spans). Provide Bar# 5, Area = 0.310, Numbers in clear span = 7, As’ =0.31 x 7 = 2.17 in2 The variation is symmetric about ‘I’. If the girder depths at ‘D’ and ‘N’ are both 40 (L/2 in inch) and that at ‘I’ is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (ft) from left (ft) 'D'(inch) (Kip) (Kip) (Kip) (kip-ft) (kip-ft) (kip-ft) ---------------------------------------------------------------------------------------------------------------------------L/2 164.04 0.00 5.760 1328.000 1048.000 2376.000 35420.000-16510.000 18910.000 (3L/8) 123.03 41.01 5.800 1990.000 1048.000 3038.000 -34450.000 15700.000 -18750.000 (L/4) 82.02 82.02 6.100 1328.000 569.100 1897.100 35690.000 16870.000 52560.000 (L/8) 41.01 123.03 6.600 1990.000 1048.000 3038.000 79820.000-42960.000 36860.000 (D) 8.2 155.84 7.300 913.500 412.200 1325.700 -35690.000-16870.000 -52560.000 (L)(Support) 0.00 164.04 8.200 4047.000 2461.000 6508.000 157400.000 90200.000 247600.000 (R)(Support) 0.00 164.04 8.200 4047.000 2461.000 6508.000 157400.000 90200.000 247600.000 (D) 8.2 172.24 7.300 913.500 412.200 1325.700 -35690.000-16870.000 -52560.000 (L/8) 41.01 205.05 6.600 1990.000 1048.000 3038.000 79820.000-42960.000 36860.000 (L/4) 82.02 246.06 6.100 1328.000 569.100 1897.100 35690.000 16870.000 52560.000 (3L/8) 123.03 287.07 5.800 1990.000 1048.000 3038.000 -34450.000 15700.000 -18750.000 (L/2) 164.04 328.08 5.760 1328.000 1048.000 2376.000 35420.000-16510.000 18910.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 69.12 69.60 73.20 79.20 87.60 98.40 87.60 79.20 73.20 69.60 69.12 inch, inch, inch, inch, inch, inch, inch, inch, inch, inch, inch, (At (At (At (At (At (At (At (At (At (At (At ‘L/2’, Span L1) ‘3L/8’, Span L1) ‘L/4’, Span L1) ‘L/8’, Span L1) depth ‘D’, Span L1) support) depth ‘D’, Span L2) ‘L/8’, Span L2) ‘L/4’, Span L2) ‘3L/8’, Span L2) ‘L/2’, Span L2) for the analysis of the, the following results are obtained. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(ft) Area(sq-ft) (Kip) (Kip) (Kip) (kip-ft) (kip-ft) (kip-ft) (kip-ft) ----------------------------------------------------------------------------------------------------------------------------L/2 164.04 45.73 2376.000 566.100 2942.100 18910.000 0.000 16400.000 0.000 3L/8 123.03 46.05 3038.000 1055.000 4093.000 0.000 -18750.000 16930.000 0.000 L/4 82.02 48.43 1897.100 662.500 2559.600 52560.000 0.000 17640.000 0.000 L/8 41.01 52.40 3038.000 1055.000 4093.000 36860.000 0.000 43280.000 0.000 D 8.2 57.96 1325.700 406.900 1732.600 0.000 -52560.000 16680.000 0.000 (L)(Support) 0.00 65.11 6508.000 2465.000 8973.000 247600.000 0.000 89980.000 0.000 (R)(Support) 0.00 65.11 6508.000 2465.000 8973.000 247600.000 0.000 89980.000 0.000 D 8.2 57.96 1325.700 406.900 1732.600 0.000 -52560.000 16680.000 0.000 L/8 41.01 52.40 3038.000 1055.000 4093.000 36860.000 0.000 43280.000 0.000 L/4 82.02 48.43 1897.100 662.500 2559.600 52560.000 0.000 17640.000 0.000 3L/8 123.03 46.05 3038.000 1055.000 4093.000 0.000 -18750.000 16930.000 0.000 L/2 164.04 45.73 2376.000 566.100 2942.100 18910.000 0.000 16400.000 0.000 ----------------------------------------------------------------------------------------------------------------------------- Table 1.3 Bar Designation, Diameter and Area ----------------------------------------------------------------Bar Size Size Cross Weight Nominal Designation Nominal Sectional Lb./Ft. Perimeter Diameter Area In. In. In2 ----------------------------------------------------------------#3 3/8 Or 0.375 0.11 0.376 1.178 #4 1/2 Or 0.500 0.20 0.668 1.571 #5 5/8 OR 0.625 0.31 1.043 1.963 #6 3/4 OR 0.750 0.44 1.502 2.356 #7 7/8 OR 0.875 0.60 2.044 2.749 #8 1.000 0.79 2.670 3.142 #9 1*1/8 or 1.128 1.00 3.400 3.544 #10 1*1/4 or 1.270 1.27 4.303 3.990 #11 1*1/2 or 1.410 1.56 5.313 4.430 #14 1*3/4 or 1.693 2.25 7.650 5.316 #15 2*1/4 or 2.257 4.00 13.600 7.088 ----------------------------------------------------------------- THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(7.25) x Av = 2.558 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 2.558 x (65.107 x 12) = 1998.488 kip At D, Vc = 2.558 x (57.961 x 12) = 1779.138 kip At L/8, Vc = 2.558 x (52.404 x 12) = 1608.564 kip At L/4, Vc = 2.558 x (48.434 x 12) = 1486.703 kip At 3L/8, Vc = 2.558 x (46.052 x 12) = 1413.586 kip At L/2, Vc = 2.558 x (45.734 x 12) = 1403.825 kip The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 98.400 inch d = h – 2 x (CC + (Stirrupbardia / 2)) = 98.400 - 2 x (1.500 + (0.310/2)) = 95.090 m, (For Example : At Support, S(reqd) At D, S(reqd) At L/8, S(reqd) At L/4, S(reqd) At 3L/8, S(reqd) At L/2, S(reqd) = = = = = = 2.17 2.17 2.17 2.17 2.17 2.17 x x x x x x 72.5 72.5 72.5 72.5 72.5 72.5 x x x x x x (95.09) / ((8973.000 - 1998.488)) (84.29 ) / ((1732.600 - 1779.138) (76.20 ) / ((4093.000 - 1608.564) (69.89 ) / ((2559.600 - 1486.703) (66.29 ) / ((4093.000 - 1413.586) (65.81 ) / ((2942.100 - 1403.825) = ) ) ) ) ) 2.145 ) = (Nominal) ) = 4.825 ) = 10.248 ) = 3.892 ) = 6.731 ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =8973.00 /(2.95 x √(7.250) x (57.42 x 12) = 1.639 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.4 - Design for Shear Force ------------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(ft) from left (ft) (inch) (inch) Area(sq-ft) (kip) (kip) (inch) (inch) from formula ------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 164.04 0.00 69.120 65.810 45.734 2942.100 1403.825 0.538 6.731 7 E(3L/8) 123.03 41.01 69.600 66.290 46.052 4093.000 1413.586 0.748 3.892 4 F(L/4) 82.02 82.02 73.200 69.890 48.434 2559.600 1486.703 0.468 10.248 10 G(L/8) 41.01 123.03 79.200 76.200 52.404 4093.000 1608.564 0.748 4.825 5 H(D) 8.2 155.84 87.600 84.290 57.961 1732.600 1779.138 0.317 (Nominal) (Nominal) I(L) Support 0.00 164.04 98.400 95.090 65.107 8973.000 1998.488 1.639 2.145 2 I(R) Support 0.00 164.04 98.400 95.090 65.107 8973.000 1998.488 1.639 2.145 2 J(D) 8.2 172.24 87.600 84.290 57.961 1732.600 1779.138 0.317 (Nominal) (Nominal) K(L/8) 41.01 205.05 79.200 76.200 52.404 4093.000 1608.564 0.748 4.825 5 L(L/4) 82.02 246.06 73.200 69.890 48.434 2559.600 1486.703 0.468 10.248 10 M(3L/8) 123.03 287.07 69.600 66.290 46.052 4093.000 1413.586 0.748 3.892 4 N(L/2) 164.04 328.08 69.120 65.810 45.734 2942.100 1403.825 0.538 6.731 7 ------------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (7 + 4 + 10 + 5 + 2) / 5 = 5.600 inch OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 5.600 x 2 = 11.200 inch STEP 2: FLEXURAL DESIGN OF BOX GIRDER As1 = M/(fs x j x d) f’c = 7.250 ksi fc = 0.4 x f’c = 0.4 x 7.250 = 2.900 ksi R = 0.5 x (fc x k x j) = 0.5 x (2.900 x 0.783 x 0.739) = 0.839 ksi (From 2nd Page of this report). R = 0.839 ksi R = 0.839 ksi = 0.839 x 12 x 12 = 120.780 ksf b = 57.42 ft d = 8.2 ft Mc = Rbd^2 kip-ft. (For Example: At Support, R = 0.839, b = 57.420 ft, d = 8.200 ft, Moment Capacity = Mc = (0.839 x 57.420 x 8.200^2) = 3238.356 kip-ft) (i) The moment due to DL and LL is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 247600.000 kip-ft, MLL+ = 89980.000 kip-ft, Mc = 3238.356 kip-ft, M+(Design) = (247600.000 + 89980.000) - 3238.356 = 334341.644 kip-ft) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kip-ft, MLL- = 0.000 kip-ft, Mc = 3238.356 kip-ft, M-(Design) = (0.000 kip-ft + 0.000 kip-ft) - 3238.356 kip-ft = -3238.356 kip-ft) (ii) The required steel area (As) at top and bottom, fs = 72.5 ksi j = 0.739 (From 2nd Page of this report). d = 95.09 ft d' = 1.5 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc x 12)/(fs x j x d) m^2 (For Example: At Support, Mc = 3238.356 kip-ft, fs = 72.500 ksi, j = 0.739, d = 95.090 inch, As1 = (3238.356 x 12)/(72.500 x 0.739 x 95.090) = 7.626 inch^2) As2+ = (M+(Design) x 12) / (fs x (d – d')) inch^2 (For Example: At Support, M+(Design) = 334341.644 kip-ft, fs = 72.500 ksi, d = 95.090 inch, d' = 1.500 inch, As2+ = (334341.644 x 12) / (72.500 x (95.090 - 1.500)) = 591.295 inch^2) As2- = (M-(Design) x 12) / (fs x (d – d')) inch^2 (For Example: At Support, M-(Design) = -3238.356 kN-m, fs = 72.500 ksi, d = 95.090 inch, d' = 1.500 inch, As2- = (-3238.356 x 12) / (72.500 x (95.090 - 1.500)) = -5.727 inch^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) inch^2 (For Example: At Support, As+ = (As1) + (As2+) = 7.626 + 591.295 = 598.921 inch^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 7.626 + -5.727 = 1.899 inch^2) As = (As+) + (As-) inch^2 (For Example: At Support, As = 598.921 + (1.899) = 600.820 inch^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 inch Table 1.5 Design for Bending Moment --------------------------------------------------------------------------------------------------------------------------------------------------Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left(inch) (inch) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (inch^2) (kip-ft) (inch^2) (inch^2) --------------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 65.81 1597.872 18910.000 0.000 16400.000 0.000 33712.128 92.203 -1597.872 1.325 93.528 E(3L/8) 41.01 66.29 1620.141 0.000 -18750.000 16930.000 0.000 15309.859 44.585 -20370.141 -46.566 -1.981 F(L/4) 123.03 69.89 1792.077 52560.000 0.000 17640.000 0.000 68407.923 171.303 -1792.077 1.405 172.707 G(L/8) 123.03 76.20 2097.900 36860.000 0.000 43280.000 0.000 78042.100 179.088 -2097.900 1.517 180.605 H(D) 155.84 84.29 2566.508 0.000 -52560.000 16680.000 0.000 14113.492 35.035 -55126.508 -103.393 -68.358 I(L) Support 164.04 95.09 3238.356 247600.000 0.000 89980.000 0.000 334341.644 598.921 -3238.356 1.899 600.820 I(R) Support 164.04 95.09 3238.356 247600.000 0.000 89980.000 0.000 334341.644 598.921 -3238.356 1.899 600.820 J(D) 172.24 84.29 2566.508 0.000 -52560.000 16680.000 0.000 14113.492 35.035 -55126.508 -103.393 -68.358 K(L/8) 205.05 76.20 2097.900 36860.000 0.000 43280.000 0.000 78042.100 179.088 -2097.900 1.517 180.605 L(L/4) 246.06 69.89 1792.077 52560.000 0.000 17640.000 0.000 68407.923 170.827 -1792.077 1.405 172.707 M(3L/8) 287.07 66.29 1620.141 0.000 -18750.000 16930.000 0.000 15309.859 44.585 -20370.141 -46.566 -1.981 N(L/2) 328.08 65.81 1597.872 18910.000 0.000 16400.000 0.000 33712.128 92.203 -1597.872 1.325 93.528 --------------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 601 inch^2 By using Reinforcement Bars #10, From Table 1.3, Cross Section Area of each bar = 1.27 inch^2 Therefore total Number of reinforcement bars = 601 /1.270 = 473 Nos. Rferring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: b1 = 689.04 in b6 = 31.5 in b7 = 21.5 in b8 = b1 - 2 x (b6 + b7) = 689.04 - 2 x (31.5 + 21.5) = 48.587 in d4 = h = 98.4 in Box width at top = width = 48.587 ft., Box width at bottom = bottomwidth = SW = 48.587 ft., Approx. height of vertical walls = 8.0 ft Number of vertical walls = number of cells + 1 = 5 + 1 = 6. By considering 0.050 ft tentative cover on either side Perimeter of box at support = Perimeter = (57.420 - 2 x 0.05) + (48.587 - 2 x 0.05) + 6 x (8.2 - 2 x 0.05) = 57.320 + 48.487 + 48.600 = 154.406666666667 ft Providing long Reinforcement bars of diameter 1.26 inch, all around the box, in two layers, Total length = 2 x perimeter = 2 x 154.407 ft = 308.813 ft. The spacing of long reinforcement bars = 308.813 x 12/473 = 7.833 inch. NOTE: In case the reinforcement spacing needs to be increased, a new ‘Design Job’ is to be created at the first tab, and the analysis is to be processed once again by increasing the moving load increment 'XINC'. But the user must be careful as this reduces the Shear Force and Bending Moments. Suggested, higher grades of concrete and steel, larger diameters of reinforcement bars may be tried. If the spacing is less than Long Bar Diameter + 3.149 mm, then, concrete pouring and compaction by needle vibrator of 2.3622 mm diameter may not be feasible. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged stirrups of diameter 10 mm as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * ************************************* Design Report port on Normal Analysis (Single-cell ACI-AASHTO) *********** ******************************************* * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Si ingle-Cell PSC Box-Girder Cross-Section * * By ACI/AASHTO * * * * DESIGN ON ANALYSIS RESULTS * * Date 02.08.2023 AT 16:54:33 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * *********** ******************************************* W Website: www.techsoftglobal.com Single-C Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Single-Cell PSC Box-Girder Cross-Section * * By ACI/AASTO * * * * DESIGN ON ANALYSIS RESULTS * * Date 02.08.2023 AT 16:54:33 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 328ft Bridge Width = Wbridge = 57.42ft Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15' Slab thickness = t = 6 inch, Wearing Surface Uniformly Distributed Load = w2 = 30 psf, n = 9 bb = 1 Clear Cover = cc = 1.5 inch Unit weight of Concrete = w = 150 pcf (pound per Cu. Ft) Loads: Live Load = 0' Wearing Surface = Lw = 30 psf Material Properties: fc = 7.25 ksi fs = 72.5 ksi For Shear Design: Stirrups Legs = 2 Provide Bar# = 5 Spacing = 7 Number of stirrups per segment = 20 NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Gridres. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the ‘Hammer Head’ and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using ‘Cantilever Form Traveler’ or CFT. (Analysis and design have considered sections From support to ‘D’, ‘D’ to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 57.42 ft Number of girders = N = 6 Width of each girder = b = 15 inch. Clear span between girders = S = [B - (Nxb/12)/(N-1)] = [(57.42 – (6x6/12)/(5] = 9.984 The c/c distance between girders = GC = c + b/12 = 9.984 + 15/12 = 11.234 ft. Unit weight of Concrete = w = 150 pcf (pound per Cu. Ft) Slab thickness = t = 6 inch, Slab Uniformly Distributed Load = w1 = (t/12) x w = (6/12) x 6 = 75 psf = 0.075 ksf Wearing Surface Uniformly Distributed Load = w2 = 30 psf, Total UDL = wDL = w1 + w2 = 75+30 =105 psf = 105/1000 ksf = 0.105 ksf Dead-load moment = MDL = wDL x S^2/10 = 0.105 x 9.984^2/.10 = 1.047 k-inch/ft AASHTO specifies Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(9.984+2)/32] x 16 = 4.7936 k ft/ft ft. Impact factor = I = 50/(S+125) = 0.370 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = 4.7936 x 0.3 = 1.438 k-ft/ft Total moment = MT = MDL + MLL + MIMP = (1.047 + 4.7936 + 1.43808) = 7.278 k-ft/ft For design = fc’ = 7.25 ksi (27.5 MPa) fc = 0.4 x fc’ = 0.4 x 7.25 = 2.9 ksi n = 9 k = n/(n+20/1.2) = 9/(9+20/2.900) = 0.783, j = 1– k/3 = 1 – 0.783/3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (2.9 x 0.783 x 0.739) = 0.839 ksi bb = 1 d req = √(MT/R/bb) = √(7.278 / 0.839 / 1) = 2.946 inch Clear Cover = cc = 1.5 inch d = (t – cc) = 6”–1.5” = 4.5 inch If (d < dreq) d = dreq d =4.5 inch Slab thickness = d + cc = 4.5 + 1.5 = 6 inch. For design = fs = 72.5 ksi Required reinforcement, As = MT x 12/ (fs x j x d) = 7.278 x 12 / (72.5 x 0.739 x 4.5) = 0.362 in2/ ft Use #5 or #6 @required spacing for inch centre to centre, to fulfill the above reinforcement reqt.) (For example: Use #5 @ 7 inch c/c or #6 @10 inch c/c) Provide Bar# 5, Area = 0.31, Spacing 7 inch c/c, As’ = 0.310 x 2.00 = 0.62 in2 Also, 2.2/ √S = 2.2/√9.984 = 0.696 > 0.67 Distribution steel, As-dist = 0.620 x As = 0.620 x 0.362 = 0.225 in2/ ft As(dist) per c/c span = GC x As = 11.234 x 0.225 in2/ ft = 2.523 in2 Use #7 @required spacing for inch centre to centre, to fulfill the above reinforcement reqt.) (For example: Use 7 nos. # 5 inch bars, to be placed within the clear spans). Provide Bar# 5, Area = 0.310, Numbers in clear span = 7, As’ =0.31 x 7 = 2.17 in2 The variation is symmetric about ‘I’. If the girder depths at ‘D’ and ‘N’ are both 40 (L/2 in inch) and that at ‘I’ is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (ft) from left (ft) 'D'(inch) (Kip) (Kip) (Kip) (kip-ft) (kip-ft) (kip-ft) ---------------------------------------------------------------------------------------------------------------------------L/2 164.04 0.00 5.760 1673.000 866.500 2539.500 50290.000-18200.000 32090.000 (3L/8) 123.03 41.01 5.800 1871.000 866.500 2737.500 -28510.000 9573.000 -18937.000 (L/4) 82.02 82.02 6.100 1131.000 367.200 1498.200 33540.000 12260.000 45800.000 (L/8) 41.01 123.03 6.600 1871.000 866.500 2737.500 74960.000-35540.000 39420.000 (D) 8.2 155.84 7.300 1281.000 441.700 1722.700 50750.000-18110.000 32640.000 (L)(Support) 0.00 164.04 8.200 5566.000 2015.000 7581.000 137800.000 67480.000 205280.000 (R)(Support) 0.00 164.04 8.200 5566.000 2015.000 7581.000 137800.000 67480.000 205280.000 (D) 8.2 172.24 7.300 1281.000 441.700 1722.700 50750.000-18110.000 32640.000 (L/8) 41.01 205.05 6.600 1871.000 866.500 2737.500 74960.000-35540.000 39420.000 (L/4) 82.02 246.06 6.100 1131.000 367.200 1498.200 33540.000 12260.000 45800.000 (3L/8) 123.03 287.07 5.800 1871.000 866.500 2737.500 -28510.000 9573.000 -18937.000 (L/2) 164.04 328.08 5.760 1673.000 866.500 2539.500 50290.000-18200.000 32090.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 69.12 69.60 73.20 79.20 87.60 98.40 87.60 79.20 73.20 69.60 69.12 inch, inch, inch, inch, inch, inch, inch, inch, inch, inch, inch, (At (At (At (At (At (At (At (At (At (At (At ‘L/2’, Span L1) ‘3L/8’, Span L1) ‘L/4’, Span L1) ‘L/8’, Span L1) depth ‘D’, Span L1) support) depth ‘D’, Span L2) ‘L/8’, Span L2) ‘L/4’, Span L2) ‘3L/8’, Span L2) ‘L/2’, Span L2) for the analysis of the, the following results are obtained. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(ft) Area(sq-ft) (Kip) (Kip) (Kip) (kip-ft) (kip-ft) (kip-ft) (kip-ft) ----------------------------------------------------------------------------------------------------------------------------L/2 164.04 33.02 2539.500 570.300 3109.800 32090.000 0.000 18030.000 0.000 3L/8 123.03 33.05 2737.500 863.000 3600.500 0.000 -18937.000 11020.000 0.000 L/4 82.02 33.24 1498.200 455.600 1953.800 45800.000 0.000 13120.000 0.000 L/8 41.01 33.44 2737.500 863.000 3600.500 39420.000 0.000 35390.000 0.000 D 8.2 34.12 1722.700 436.600 2159.300 32640.000 0.000 17900.000 0.000 (L)(Support) 0.00 35.27 7581.000 1987.000 9568.000 205280.000 0.000 66950.000 0.000 (R)(Support) 0.00 35.27 7581.000 1987.000 9568.000 205280.000 0.000 66950.000 0.000 D 8.2 34.12 1722.700 436.600 2159.300 32640.000 0.000 17900.000 0.000 L/8 41.01 33.44 2737.500 863.000 3600.500 39420.000 0.000 35390.000 0.000 L/4 82.02 33.24 1498.200 455.600 1953.800 45800.000 0.000 13120.000 0.000 3L/8 123.03 33.05 2737.500 863.000 3600.500 0.000 -18937.000 11020.000 0.000 L/2 164.04 33.02 2539.500 570.300 3109.800 32090.000 0.000 18030.000 0.000 ----------------------------------------------------------------------------------------------------------------------------- Table 1.3 Bar Designation, Diameter and Area ----------------------------------------------------------------Bar Size Size Cross Weight Nominal Designation Nominal Sectional Lb./Ft. Perimeter Diameter Area In. In. In2 ----------------------------------------------------------------#3 3/8 Or 0.375 0.11 0.376 1.178 #4 1/2 Or 0.500 0.20 0.668 1.571 #5 5/8 OR 0.625 0.31 1.043 1.963 #6 3/4 OR 0.750 0.44 1.502 2.356 #7 7/8 OR 0.875 0.60 2.044 2.749 #8 1.000 0.79 2.670 3.142 #9 1*1/8 or 1.128 1.00 3.400 3.544 #10 1*1/4 or 1.270 1.27 4.303 3.990 #11 1*1/2 or 1.410 1.56 5.313 4.430 #14 1*3/4 or 1.693 2.25 7.650 5.316 #15 2*1/4 or 2.257 4.00 13.600 7.088 ----------------------------------------------------------------- THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(7.25) x Av = 2.558 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 2.558 x (35.266 x 12) = 1082.505 kip At D, Vc = 2.558 x (34.119 x 12) = 1047.298 kip At L/8, Vc = 2.558 x (33.444 x 12) = 1026.578 kip At L/4, Vc = 2.558 x (33.235 x 12) = 1020.163 kip At 3L/8, Vc = 2.558 x (33.047 x 12) = 1014.392 kip At L/2, Vc = 2.558 x (33.024 x 12) = 1013.686 kip The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 98.400 inch d = h – 2 x (CC + (Stirrupbardia / 2)) = 98.400 - 2 x (1.500 + (0.310/2)) = 95.090 m, (For Example : At Support, S(reqd) At D, S(reqd) At L/8, S(reqd) At L/4, S(reqd) At 3L/8, S(reqd) At L/2, S(reqd) = = = = = = 2.17 2.17 2.17 2.17 2.17 2.17 x x x x x x 72.5 72.5 72.5 72.5 72.5 72.5 x x x x x x (95.09) / ((9568.000 - 1082.505)) (84.29 ) / ((2159.300 - 1047.298) (76.20 ) / ((3600.500 - 1026.578) (69.89 ) / ((1953.800 - 1020.163) (66.29 ) / ((3600.500 - 1014.392) (65.81 ) / ((3109.800 - 1013.686) = ) ) ) ) ) 1.763 ) = 11.925 ) = 4.658 ) = 11.777 ) = 4.033 ) = 4.939 ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =9568.00 /(2.95 x √(7.250) x (57.42 x 12) = 1.748 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.4 - Design for Shear Force ------------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(ft) from left (ft) (inch) (inch) Area(sq-ft) (kip) (kip) (inch) (inch) from formula ------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 164.04 0.00 69.120 65.810 33.024 3109.800 1013.686 0.568 4.939 5 E(3L/8) 123.03 41.01 69.600 66.290 33.047 3600.500 1014.392 0.658 4.033 4 F(L/4) 82.02 82.02 73.200 69.890 33.235 1953.800 1020.163 0.357 11.777 12 G(L/8) 41.01 123.03 79.200 76.200 33.444 3600.500 1026.578 0.658 4.658 5 H(D) 8.2 155.84 87.600 84.290 34.119 2159.300 1047.298 0.395 11.925 12 I(L) Support 0.00 164.04 98.400 95.090 35.266 9568.000 1082.505 1.748 1.763 2 I(R) Support 0.00 164.04 98.400 95.090 35.266 9568.000 1082.505 1.748 1.763 2 J(D) 8.2 172.24 87.600 84.290 34.119 2159.300 1047.298 0.395 11.925 12 K(L/8) 41.01 205.05 79.200 76.200 33.444 3600.500 1026.578 0.658 4.658 5 L(L/4) 82.02 246.06 73.200 69.890 33.235 1953.800 1020.163 0.357 11.777 12 M(3L/8) 123.03 287.07 69.600 66.290 33.047 3600.500 1014.392 0.658 4.033 4 N(L/2) 164.04 328.08 69.120 65.810 33.024 3109.800 1013.686 0.568 4.939 5 ------------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (5 + 4 + 12 + 5 + 12 + 2) / 6 = 6.667 inch OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 6.667 x 2 = 13.333 inch STEP 2: FLEXURAL DESIGN OF BOX GIRDER As1 = M/(fs x j x d) f’c = 7.250 ksi fc = 0.4 x f’c = 0.4 x 7.250 = 2.900 ksi R = 0.5 x (fc x k x j) = 0.5 x (2.900 x 0.783 x 0.739) = 0.839 ksi (From 2nd Page of this report). R = 0.839 ksi R = 0.839 ksi = 0.839 x 12 x 12 = 120.780 ksf b = 57.42 ft d = 8.2 ft Mc = Rbd^2 kip-ft. (For Example: At Support, R = 0.839, b = 57.420 ft, d = 8.200 ft, Moment Capacity = Mc = (0.839 x 57.420 x 8.200^2) = 3238.356 kip-ft) (i) The moment due to DL and LL is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 205280.000 kip-ft, MLL+ = 66950.000 kip-ft, Mc = 3238.356 kip-ft, M+(Design) = (205280.000 + 66950.000) - 3238.356 = 268991.644 kip-ft) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kip-ft, MLL- = 0.000 kip-ft, Mc = 3238.356 kip-ft, M-(Design) = (0.000 kip-ft + 0.000 kip-ft) - 3238.356 kip-ft = -3238.356 kip-ft) (ii) The required steel area (As) at top and bottom, fs = 72.5 ksi j = 0.739 (From 2nd Page of this report). d = 95.09 ft d' = 1.5 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc x 12)/(fs x j x d) m^2 (For Example: At Support, Mc = 3238.356 kip-ft, fs = 72.500 ksi, j = 0.739, d = 95.090 inch, As1 = (3238.356 x 12)/(72.500 x 0.739 x 95.090) = 7.626 inch^2) As2+ = (M+(Design) x 12) / (fs x (d – d')) inch^2 (For Example: At Support, M+(Design) = 268991.644 kip-ft, fs = 72.500 ksi, d = 95.090 inch, d' = 1.500 inch, As2+ = (268991.644 x 12) / (72.500 x (95.090 - 1.500)) = 475.721 inch^2) As2- = (M-(Design) x 12) / (fs x (d – d')) inch^2 (For Example: At Support, M-(Design) = -3238.356 kN-m, fs = 72.500 ksi, d = 95.090 inch, d' = 1.500 inch, As2- = (-3238.356 x 12) / (72.500 x (95.090 - 1.500)) = -5.727 inch^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) inch^2 (For Example: At Support, As+ = (As1) + (As2+) = 7.626 + 475.721 = 483.348 inch^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 7.626 + -5.727 = 1.899 inch^2) As = (As+) + (As-) inch^2 (For Example: At Support, As = 483.348 + (1.899) = 485.247 inch^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 inch Table 1.5 Design for Bending Moment --------------------------------------------------------------------------------------------------------------------------------------------------Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left(inch) (inch) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (kip-ft) (inch^2) (kip-ft) (inch^2) (inch^2) --------------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 65.81 1597.872 32090.000 0.000 18030.000 0.000 48522.128 130.321 -1597.872 1.325 131.645 E(3L/8) 41.01 66.29 1620.141 0.000 -18937.000 11020.000 0.000 9399.859 29.487 -20557.141 -47.044 -17.557 F(L/4) 123.03 69.89 1792.077 45800.000 0.000 13120.000 0.000 57127.923 144.003 -1792.077 1.405 145.408 G(L/8) 123.03 76.20 2097.900 39420.000 0.000 35390.000 0.000 72712.100 167.278 -2097.900 1.517 168.795 H(D) 155.84 84.29 2566.508 32640.000 0.000 17900.000 0.000 47973.492 102.729 -2566.508 1.687 104.417 I(L) Support 164.04 95.09 3238.356 205280.000 0.000 66950.000 0.000 268991.644 483.348 -3238.356 1.899 485.247 I(R) Support 164.04 95.09 3238.356 205280.000 0.000 66950.000 0.000 268991.644 483.348 -3238.356 1.899 485.247 J(D) 172.24 84.29 2566.508 32640.000 0.000 17900.000 0.000 47973.492 102.729 -2566.508 1.687 104.417 K(L/8) 205.05 76.20 2097.900 39420.000 0.000 35390.000 0.000 72712.100 167.278 -2097.900 1.517 168.795 L(L/4) 246.06 69.89 1792.077 45800.000 0.000 13120.000 0.000 57127.923 143.527 -1792.077 0.929 144.457 M(3L/8) 287.07 66.29 1620.141 0.000 -18937.000 11020.000 0.000 9399.859 29.487 -20557.141 -47.044 -17.557 N(L/2) 328.08 65.81 1597.872 32090.000 0.000 18030.000 0.000 48522.128 130.321 -1597.872 1.325 131.645 --------------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 485 inch^2 By using Reinforcement Bars #10, From Table 1.3, Cross Section Area of each bar = 1.27 inch^2 Therefore total Number of reinforcement bars = 485 /1.270 = 382 Nos. Rferring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: DW = 57.42 ft C1 = 7.75 ft C2 = 0.000 ft Iw = 1.792 ft SW = DW - 2 x (C1 + C2 + Iw) = 57.420 - 2 x (7.75 + 0.000 + 1.792) = 38.336 ft D = h = 8.2 ft Box width at top = width = 38.336 ft., Box width at bottom = bottomwidth = SW = 38.336 ft., Approx. height of vertical walls = 8.2 ft Number of vertical walls = number of cells + 1 = 1 + 1 = 2. By considering 0.050 ft tentative cover on either side Perimeter of box at support = Perimeter = (57.420 - 2 x 0.05) + (38.336 - 2 x 0.05) + 2 x (8.2 - 2 x 0.05) = 57.320 + 38.236 + 16.200 = 111.756 ft Providing long Reinforcement bars of diameter 1.26 inch, all around the box, in two layers, Total length = 2 x perimeter = 2 x 111.756 ft = 223.512 ft. The spacing of long reinforcement bars = 223.512 x 12/382 = 7.020 inch. NOTE: In case the reinforcement spacing needs to be increased, a new ‘Design Job’ is to be created at the first tab, and the analysis is to be processed once again by increasing the moving load increment 'XINC'. But the user must be careful as this reduces the Shear Force and Bending Moments. Suggested, higher grades of concrete and steel, larger diameters of reinforcement bars may be tried. If the spacing is less than Long Bar Diameter + 3.149 mm, then, concrete pouring and compaction by needle vibrator of 2.3622 mm diameter may not be feasible. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged stirrups of diameter 10 mm as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * ************************************* Design Report on Normal Analysis (Multi-cell BS / Eurocode2) ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in BS / Eurocode2 * * * * Date 03.08.2023 AT 15:11:54 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Website: www.techsoftglobal.com Multi-Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in BS / Eurocode2 * * * * Date 03.08.2023 AT 15:11:54 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 100 m Bridge Width = Wbridge = 17.5 m Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15 m Slab thickness = t = 0.2 m, Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, n = 9 bb = 1 Clear Cover = cc = 0.040 m Unit weight of Concrete = w = 2.4 Tons/Cum For Slab Bar Diameter = Slabbardia = 10 mm. Loads: Wearing Surface = Lw = 0.0014 MPa Material Properties: f'c = 50 MPa fs = 500 MPa For Shear Design: Stirrups Legs = Legs = 2 Provide Bar Diameter = Stirrupbardia = 20 mm For Flexural Design: Provide Main Long Bar Diameter = Longbardia = 32 mm NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Girders. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the 'Hammer Head' and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using 'Cantilever Form Traveler' or CFT. (Analysis and design have considered sections From support to 'D', 'D' to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 17.5 m Number of girders = N = 6 Width of each girder = b = 15 m Clear span between girders = S = [B - (Nxb)/(N-1)] = [(17.5 - (6x15)/(6-1)] = -14.5 m The c/c distance between girders = GC = c + b = -14.5 + 15 = 0.5 m Unit weight of Concrete = w = 2.4 Tons/Cum Slab thickness = t = 0.2 m Slab Uniformly Distributed Load = w1 = t x w = 0.2 x 2.4 = 0.48 MPa Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, Total UDL = wDL = w1 + w2 = 0.48+0.0014 =0.4814 MPa = 0.4814/1000 ksf = 0.000 MPa Dead-load moment = MDL = wDL x S^2/10 = 0.0004814 x -14.5^2/.10 = 0.010 kN-m Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(-14.5+2)/32] x 16 = -5 k kN-m Impact factor = I = 50/(S+125) = 0.452 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = -5 x 0.3 = -1.500 kN-m Total moment = MT = MDL + MLL + MIMP = (0.010 + -5 + -1.5) = -6.490 kN-m For design = f'c = 50 MPa fc = 0.4 x f'c = 0.4 x 50 = 20 N/mm^2 n = 9 k = n /(n + f'c / fc) = 9 / (9 + 50 / 20) = 20.000, j = 1 - k / 3 = 1 – 0.783 / 3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (20 x 0.783 x 0.739) = 5.784 ksi bb = 1 d reqd = √(MT/R/bb) = √(-6.490 / 5.784 / 1) = NaN mm Clear Cover = cc = 0.040 m d = (t - cc) = 0.2 - 0.04 = 0.16 m If (d < d reqd) d = d req d =0.16 mm^2 Slab thickness = d + cc = 0.16 + 0.04 = 0.2 m. For design = fs = 500 Mpa Required reinforcement, As = MT / (fs x j x d) = -6.490 / (500 x 0.739 x 0.16) = -0.110 mm^2 Provide Bar Diamete = 20 Spacing 120 m c/c, As' = 20.000 x 2.00 = 40.00 mm^2 Also, 2.2/ √S = 2.2/√-14.5 = NaN > 0.67 Distribution steel, As-dist = 40.000 x As = 40.000 x -0.110 = -4.390 mm^2 As(dist) per c/c span = GC x As = 0.5 x -4.390 mm^2 = -2.195 mm^2 Provide Bar Diameter = Slabbardia = 10 mm Numbers in clear span = 7, As' =10 x 120 = 1200 mm^2. The variation is symmetric about 'I'. If the girder depths at 'D' and 'N' are both 40 (L/2 in m) and that at 'I' is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (m) from left (m) 'D'(m) (kN) ( kN) (kN) (kN-m) (kN-m) (kN-m) ---------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 19540.000 9946.000 29486.000 170400.000 77720.000 248120.000 (3L/8) 37.50 12.50 1.300 11120.000 5032.000 16152.000 104600.000-45080.000 59520.000 (L/4) 25.00 25.00 1.600 8298.000 3478.000 11776.000 70270.000-29620.000 40650.000 (L/8) 12.50 37.50 1.900 15850.000 6448.000 22298.000 102700.000-43480.000 59220.000 (D) 2.5 47.50 2.200 16520.000 7610.000 24130.000 93720.000 41280.000 135000.000 (L)(Support) 0.00 50.00 2.500 19540.000 9946.000 29486.000 217100.000102500.000 319600.000 (R)(Support) 0.00 50.00 2.500 19540.000 9946.000 29486.000 217100.000102500.000 319600.000 (D) 2.5 52.50 2.200 16520.000 7610.000 24130.000 93720.000 41280.000 135000.000 (L/8) 12.50 62.50 1.900 15850.000 6448.000 22298.000 102700.000-43480.000 59220.000 (L/4) 25.00 75.00 1.600 8298.000 3478.000 11776.000 70270.000-29620.000 40650.000 (3L/8) 37.50 87.50 1.300 11120.000 5032.000 16152.000 104600.000-45080.000 59520.000 (L/2) 50.00 100.00 1.000 19540.000 9946.000 29486.000 170400.000 77720.000 248120.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 0.2 m, (At 'L/2', Span L1) 0 m, (At '3L/8', Span L1) 1.5 m, (At 'L/4', Span L1) 0.2 m, (At 'L/8', Span L1) 17.500 m, (At depth 'D', Span L1) 2.5 m, (At support) 17.500 m, (At depth 'D', Span L2) 0.2 m, (At 'L/8', Span L2) 1.5 m, (At 'L/4', Span L2) 0 m, (At '3L/8', Span L2) 0.2 m, (At 'L/2', Span L2) Using the analysis of the girder the following results are obtained. STEP 1: SHEAR DESIGN OF BOX GIRDER. Combination of Dead and Live Loads The dead load and (live load + Impact) shear forces and bending moments calculated earlier at various sections of the bridge are now combined to obtain the design (maximum positive and/or negative) shear forces and bending moments. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(m) Area(m) (kN) (kN) (kN) (kN-m) (kN-m) (kN-m) (kN-m) ----------------------------------------------------------------------------------------------------------------------------L/2 50.00 3.46 29486.000 9389.000 38875.000 248120.000 0.000 71470.000 0.000 3L/8 37.50 3.42 16152.000 4525.000 20677.000 59520.000 0.000 41300.000 0.000 L/4 25.00 3.40 11776.000 3179.000 14955.000 40650.000 0.000 26830.000 0.000 L/8 12.50 3.57 22298.000 5896.000 28194.000 59220.000 0.000 39740.000 0.000 D 2.5 3.77 24130.000 7040.000 31170.000 135000.000 0.000 37470.000 0.000 (L)(Support) 0.00 5.20 29486.000 9389.000 38875.000 319600.000 0.000 94900.000 0.000 (R)(Support) 0.00 5.20 29486.000 9389.000 38875.000 319600.000 0.000 94900.000 0.000 D 2.5 3.77 24130.000 7040.000 31170.000 135000.000 0.000 37470.000 0.000 L/8 12.50 3.57 22298.000 5896.000 28194.000 59220.000 0.000 39740.000 0.000 L/4 25.00 3.40 11776.000 3179.000 14955.000 40650.000 0.000 26830.000 0.000 3L/8 37.50 3.42 16152.000 4525.000 20677.000 59520.000 0.000 41300.000 0.000 L/2 50.00 3.46 29486.000 9389.000 38875.000 248120.000 0.000 71470.000 0.000 ----------------------------------------------------------------------------------------------------------------------------- THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(50) x Av = 6.718 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 6.718 x 5.204 x 10^6 = 34.958 x 10^6 N. = 34.958 At D, Vc = 6.718 x 3.769 x 10^6 = 25.318 x 10^6 N. = 25.318 x At L/8, Vc = 6.718 x 3.568 x 10^6 = 23.968 x 10^6 N. = 23.968 x At L/4, Vc = 6.718 x 3.396 x 10^6 = 22.813 x 10^6 N. = 22.813 x At 3L/8, Vc = 6.718 x 3.418 x 10^6 = 22.960 x 10^6 N. = 22.960 x At L/2, Vc = 6.718 x 3.463 x 10^6 = 23.263 x 10^6 N. = 23.263 x x 10^3 kN = 34957.945 kN. 10^3 kN = 25318.312 kN. 10^3 kN = 23968.091 kN. 10^3 kN = 22812.679 kN. 10^3 kN = 22960.464 kN. 10^3 kN = 23262.752 kN. The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 2.500 m, cc = 0.040 m, d = h – 2 x cc = 2.500 - 2 x 0.040 = 2.420 m, fs = 500 Mpa. If 2-legged (Legs=2), 20 mm diameter (Stirrupbardia = 20) stirrups are used, As = Legs x (3.1416 x Stirrupbardia x Stirrupbardia / 4) = 2 x (3.1416 x 20 x 20 / 4) = 2 x 314.16 = 628.32 mm^2. (For Example : At Support, S(reqd) = 628.32 x 500 x (2.42 x 1000) / ((38875.000 - 34957.945) x 1000) = 194.092 ) At D, S(reqd) = 628.32 x 500 x (2.12 x 1000) / ((31170.000 - 25318.312) x 1000) = 113.817 ) At L/8, S(reqd) = 628.32 x 500 x (1.82 x 1000) / ((28194.000 - 23968.091) x 1000) = 135.301 ) At L/4, S(reqd) = 628.32 x 500 x (1.52 x 1000) / ((14955.000 - 22812.679) x 1000) = (Nominal) ) At 3L/8, S(reqd) = 628.32 x 500 x (1.22 x 1000) / ((20677.000 - 22960.464) x 1000) = (Nominal) ) At L/2, S(reqd) = 628.32 x 500 x (0.92 x 1000) / ((38875.000 - 23262.752) x 1000) = 18.513 ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =38875.00 /(2.95 x √(50.000) x (17500.00 x 1000) = 0.106 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.3 - Design for Shear Force -----------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(m) from left (m) (m) (m) Area(sq-m) (kN) (kN) (mm) (mm) from formula(mm) -----------------------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 0.920 3.463 38875.000 23262.752 0.106 18.513 19 3L/8 37.50 12.50 1.300 1.220 3.418 20677.000 22960.464 0.057 (Nominal) (Nominal) L/4 25.00 25.00 1.600 1.520 3.396 14955.000 22812.679 0.041 (Nominal) (Nominal) L/8 12.50 37.50 1.900 1.820 3.568 28194.000 23968.091 0.077 135.301 135 D 2.5 47.50 2.200 2.120 3.769 31170.000 25318.312 0.085 113.817 114 (L) Support 0.00 50.00 2.500 2.420 5.204 38875.000 34957.945 0.106 194.092 194 (R) Support 0.00 50.00 2.500 2.420 5.204 38875.000 34957.945 0.106 194.092 194 D 2.5 52.50 2.200 2.120 3.769 31170.000 25318.312 0.085 113.817 114 L/8 12.50 62.50 1.900 1.820 3.568 28194.000 23968.091 0.077 135.301 135 L/4 25.00 75.00 1.600 1.520 3.396 14955.000 22812.679 0.041 (Nominal) (Nominal) 3L/8 37.50 87.50 1.300 1.220 3.418 20677.000 22960.464 0.057 (Nominal) (Nominal) L/2 50.00 100.00 1.000 0.920 3.463 38875.000 23262.752 0.106 18.513 19 -----------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (19 + 135 + 114 + 194 / 4 = 115.500 mm = 11.550 cm = 12 cm OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 115.5 x 2 = 231 mm = 23 cm STEP 2: FLEXURAL DESIGN OF BOX GIRDER. For doubly reinforced beams, d < d(reqd); i.e., M > Mc As1 = M/(fs x j x d) f'c = 50 ksi (27.5 MPa) fc = 0.4 x f'c = 0.4 x 50 = 20 ksi R = 0.5 x (fc x k x j) = 0.5 x (50.000 x 0.783 x 0.739) = 5.784 ksi (From 2nd Page of this report). R = 5.784 ksi = 5.784 x 1000 = 5784.50 ksf b = 17.5 m d = 2.42 m Mc = Rbd^2 kN-m. (For Example: At Support, R = 5784.499, b = 17.500 m, d = 2.420 m, Mc = (5784.499 x 17.500 x 2.420^2) = 592835.955 kN-m) (i) The moment is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 319600.000 kN-m, MLL+ = 94900.000 kN-m, Mc = 592835.955 kN-m, M+(Design) = (319600.000 + 94900.000) - 592835.955 = -178335.955 kN-m) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kN-m, MLL- = 0.000 kN-m, Mc = 592835.955 kN-m, M-(Design) = (0.000 kN-m + 0.000 kN-m) - 592835.955 kN-m = -592835.955 kN-m) (ii) The required steel area (As) at top and bottom, fs = 500 ksi j = 0.739 (From 2nd Page of this report). d = 2.42 m d' = 0.04 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc)/(fs x j x d) m^2 (For Example: At Support, Mc = 592835.955 kN-m, fs = 500.000 N/mm^2, j = 0.739, d = 2.420 m, As1 = (592835.955)/(500.000 x 1000 x 0.739 x 2.420) = 0.663 m^2) As2+ = (M+(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M+(Design) = -178335.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2+ = (-178335.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.150 m^2) As2- = (M-(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M-(Design) = -592835.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2- = (-592835.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.498 m^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) m^2 (For Example: At Support, As+ = (As1) + (As2+) = 0.663 + -0.150 = 0.513 m^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 0.663 + -0.498 = 0.165 m^2) As = (As+) + (As-) m^2 (For Example: At Support, As = 0.513 + (0.165) = 0.678 m^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 m Table 1.4 Design for Bending Moment --------------------------------------------------------------------------------------------------------------------------------------------Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left (m) (m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (m^2) (kN-m) (m^2) (m^2) --------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 0.92 85680.000 248120.000 0.000 71470.000 0.000 233910.000 0.784 -85680.000 0.057 0.841 E(3L/8) 12.50 1.22 150668.847 59520.000 0.000 41300.000 0.000 -49848.847 0.250 -150668.847 0.079 0.328 F(L/4) 37.50 1.52 233878.866 40650.000 0.000 26830.000 0.000 -166398.866 0.191 -233878.866 0.100 0.292 G(L/8) 37.50 1.82 335310.057 59220.000 0.000 39740.000 0.000 -236350.057 0.233 -335310.057 0.122 0.355 H(D) 47.50 2.12 454962.420 135000.000 0.000 37470.000 0.000 -282492.420 0.309 -454962.420 0.143 0.452 I(L) Support 50.00 2.42 592835.955 319600.000 0.000 94900.000 0.000 -178335.955 0.513 -592835.955 0.165 0.678 I(R) Support 50.00 2.42 592835.955 319600.000 0.000 94900.000 0.000 -178335.955 0.513 -592835.955 0.165 0.678 J(D) 52.50 2.12 454962.420 135000.000 0.000 37470.000 0.000 -282492.420 0.309 -454962.420 0.143 0.452 K(L/8) 62.50 1.82 335310.057 59220.000 0.000 39740.000 0.000 -236350.057 0.233 -335310.057 0.122 0.355 L(L/4) 75.00 1.52 233878.866 40650.000 0.000 26830.000 0.000 -166398.866 0.123 -233878.866 0.032 0.155 M(3L/8) 87.50 1.22 150668.847 59520.000 0.000 41300.000 0.000 -49848.847 0.250 -150668.847 0.079 0.328 N(L/2) 100.00 0.92 85680.000 248120.000 0.000 71470.000 0.000 233910.000 0.784 -85680.000 0.057 0.841 --------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 0.678 m^2 = 677695.509 mm^2 By using Reinforcement Bars of Diameter = 32.000 mm Cross Section Area of each bar = Pi x d^2 / 4 = 3.1416 x Longbardia^2 / 4 = 3.1416 x 32 ^2 / 4 = 804.250 mm^2 Therefore total Number of reinforcement bars = 677696 /804 = 843 Nos. Referring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: b1 = 17.500 m b6 = 0.800 m b7 = 0.546 m b8 = b1 - 2 x (b6 + b7) = 17.500 - 2 x (0.800 + 0.546) = 14.808 m d4 = h = 2.5 m Box width at top = width = 14.808 m., Box width at bottom = bottomwidth = SW = 14.808 m., Approx. height of vertical walls = 0.303 m Number of vertical walls = number of cells + 1 = 5 + 1 = 6. By considering 1.5 m tentative cover on either side, Perimeter of box at support = Perimeter = (17.500 - 2 x 0.05) + (14.808 - 2 x 0.05) + 6 x (2.5 - 2 x 0.05) = 17.400 + 14.708 + 14.400 = 46.508 m Providing long Reinforcement bars of diameter 32 mm, all around the box, in two layers, Total length = 2 x perimeter = 2 x 46.508 m = 93.016 m. The spacing of long reinforcement bars = 93.016 x 1000/842.643 = 110.386 mm. = 110 mm. = 11 cm. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged #10 stirrups are used as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * ************************************* Design Report ort o on Normal Analysis (Single-cell BS / Eurocode2) *********** ******************************************* * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Si ingle-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in BS / Eurocode2 * * * * Date 02.08.2023 AT 17:09:18 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * *********** ******************************************* W Website: www.techsoftglobal.com Single-C Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Single-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in BS / Eurocode2 * * * * Date 02.08.2023 AT 17:09:18 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 100 m Bridge Width = Wbridge = 17.5 m Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15 m Slab thickness = t = 0.2 m, Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, n = 9 bb = 1 Clear Cover = cc = 0.040 m Unit weight of Concrete = w = 2.4 Tons/Cum For Slab Bar Diameter = Slabbardia = 10 mm. Loads: Wearing Surface = Lw = 0.0014 MPa Material Properties: f'c = 50 MPa fs = 500 MPa For Shear Design: Stirrups Legs = Legs = 2 Provide Bar Diameter = Stirrupbardia = 20 mm For Flexural Design: Provide Main Long Bar Diameter = Longbardia = 32 mm NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Girders. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the 'Hammer Head' and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using 'Cantilever Form Traveler' or CFT. (Analysis and design have considered sections From support to 'D', 'D' to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 17.5 m Number of girders = N = 6 Width of each girder = b = 15 m Clear span between girders = S = [B - (Nxb)/(N-1)] = [(17.5 - (6x15)/(6-1)] = -14.5 m The c/c distance between girders = GC = c + b = -14.5 + 15 = 0.5 m Unit weight of Concrete = w = 2.4 Tons/Cum Slab thickness = t = 0.2 m Slab Uniformly Distributed Load = w1 = t x w = 0.2 x 2.4 = 0.48 MPa Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, Total UDL = wDL = w1 + w2 = 0.48+0.0014 =0.4814 MPa = 0.4814/1000 ksf = 0.000 MPa Dead-load moment = MDL = wDL x S^2/10 = 0.0004814 x -14.5^2/.10 = 0.010 kN-m Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(-14.5+2)/32] x 16 = -5 k kN-m Impact factor = I = 50/(S+125) = 0.452 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = -5 x 0.3 = -1.500 kN-m Total moment = MT = MDL + MLL + MIMP = (0.010 + -5 + -1.5) = -6.490 kN-m For design = f'c = 50 MPa fc = 0.4 x f'c = 0.4 x 50 = 20 N/mm^2 n = 9 k = n /(n + f'c / fc) = 9 / (9 + 50 / 20) = 20.000, j = 1 - k / 3 = 1 – 0.783 / 3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (20 x 0.783 x 0.739) = 5.784 ksi bb = 1 d reqd = √(MT/R/bb) = √(-6.490 / 5.784 / 1) = NaN mm Clear Cover = cc = 0.040 m d = (t - cc) = 0.2 - 0.04 = 0.16 m If (d < d reqd) d = d req d =0.16 mm^2 Slab thickness = d + cc = 0.16 + 0.04 = 0.2 m. For design = fs = 500 Mpa Required reinforcement, As = MT / (fs x j x d) = -6.490 / (500 x 0.739 x 0.16) = -0.110 mm^2 Provide Bar Diamete = 20 Spacing 120 m c/c, As' = 20.000 x 2.00 = 40.00 mm^2 Also, 2.2/ √S = 2.2/√-14.5 = NaN > 0.67 Distribution steel, As-dist = 40.000 x As = 40.000 x -0.110 = -4.390 mm^2 As(dist) per c/c span = GC x As = 0.5 x -4.390 mm^2 = -2.195 mm^2 Provide Bar Diameter = Slabbardia = 10 mm Numbers in clear span = 7, As' =10 x 120 = 1200 mm^2. The variation is symmetric about 'I'. If the girder depths at 'D' and 'N' are both 40 (L/2 in m) and that at 'I' is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (m) from left (m) 'D'(m) (kN) ( kN) (kN) (kN-m) (kN-m) (kN-m) ---------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 12750.000 4817.000 17567.000 103600.000 37060.000 140660.000 (3L/8) 37.50 12.50 1.300 9734.000 2790.000 12524.000 96060.000-27860.000 68200.000 (L/4) 25.00 25.00 1.600 10440.000 2529.000 12969.000 95910.000 23910.000 119820.000 (L/8) 12.50 37.50 1.900 20070.000 4948.000 25018.000 119400.000 29950.000 149350.000 (D) 2.5 47.50 2.200 20070.000 4948.000 25018.000 77520.000 21010.000 98530.000 (L)(Support) 0.00 50.00 2.500 12750.000 4817.000 17567.000 133400.000 49060.000 182460.000 (R)(Support) 0.00 50.00 2.500 12750.000 4817.000 17567.000 133400.000 49060.000 182460.000 (D) 2.5 52.50 2.200 20070.000 4948.000 25018.000 77520.000 21010.000 98530.000 (L/8) 12.50 62.50 1.900 20070.000 4948.000 25018.000 119400.000 29950.000 149350.000 (L/4) 25.00 75.00 1.600 10440.000 2529.000 12969.000 95910.000 23910.000 119820.000 (3L/8) 37.50 87.50 1.300 9734.000 2790.000 12524.000 96060.000-27860.000 68200.000 (L/2) 50.00 100.00 1.000 12750.000 4817.000 17567.000 103600.000 37060.000 140660.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 0.2 m, (At 'L/2', Span L1) 0 m, (At '3L/8', Span L1) 1.5 m, (At 'L/4', Span L1) 0.2 m, (At 'L/8', Span L1) 17.500 m, (At depth 'D', Span L1) 2.5 m, (At support) 17.500 m, (At depth 'D', Span L2) 0.2 m, (At 'L/8', Span L2) 1.5 m, (At 'L/4', Span L2) 0 m, (At '3L/8', Span L2) 0.2 m, (At 'L/2', Span L2) Using the analysis of the girder the following results are obtained. STEP 1: SHEAR DESIGN OF BOX GIRDER. Combination of Dead and Live Loads The dead load and (live load + Impact) shear forces and bending moments calculated earlier at various sections of the bridge are now combined to obtain the design (maximum positive and/or negative) shear forces and bending moments. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(m) Area(m) (kN) (kN) (kN) (kN-m) (kN-m) (kN-m) (kN-m) ----------------------------------------------------------------------------------------------------------------------------L/2 50.00 3.47 17567.000 4448.000 22015.000 140660.000 0.000 33250.000 0.000 3L/8 37.50 3.40 12524.000 2223.000 14747.000 68200.000 0.000 24840.000 0.000 L/4 25.00 3.34 12969.000 1943.000 14912.000 119820.000 0.000 18470.000 0.000 L/8 12.50 3.28 25018.000 3890.000 28908.000 149350.000 0.000 23960.000 0.000 D 2.5 3.26 25018.000 3890.000 28908.000 98530.000 0.000 16400.000 0.000 (L)(Support) 0.00 3.28 17567.000 4448.000 22015.000 182460.000 0.000 44360.000 0.000 (R)(Support) 0.00 3.28 17567.000 4448.000 22015.000 182460.000 0.000 44360.000 0.000 D 2.5 3.26 25018.000 3890.000 28908.000 98530.000 0.000 16400.000 0.000 L/8 12.50 3.28 25018.000 3890.000 28908.000 149350.000 0.000 23960.000 0.000 L/4 25.00 3.34 12969.000 1943.000 14912.000 119820.000 0.000 18470.000 0.000 3L/8 37.50 3.40 12524.000 2223.000 14747.000 68200.000 0.000 24840.000 0.000 L/2 50.00 3.47 17567.000 4448.000 22015.000 140660.000 0.000 33250.000 0.000 ----------------------------------------------------------------------------------------------------------------------------THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(50) x Av = 6.718 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 6.718 x 3.275 x 10^6 = 22.000 x 10^6 N. = 22.000 At D, Vc = 6.718 x 3.264 x 10^6 = 21.926 x 10^6 N. = 21.926 x At L/8, Vc = 6.718 x 3.280 x 10^6 = 22.033 x 10^6 N. = 22.033 x At L/4, Vc = 6.718 x 3.344 x 10^6 = 22.463 x 10^6 N. = 22.463 x At 3L/8, Vc = 6.718 x 3.398 x 10^6 = 22.826 x 10^6 N. = 22.826 x At L/2, Vc = 6.718 x 3.473 x 10^6 = 23.330 x 10^6 N. = 23.330 x x 10^3 kN = 21999.860 kN. 10^3 kN = 21925.967 kN. 10^3 kN = 22033.447 kN. 10^3 kN = 22463.368 kN. 10^3 kN = 22826.114 kN. 10^3 kN = 23329.928 kN. The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 2.500 m, cc = 0.040 m, d = h – 2 x cc = 2.500 - 2 x 0.040 = 2.420 m, fs = 500 Mpa. If 2-legged (Legs=2), 20 mm diameter (Stirrupbardia = 20) stirrups are used, As = Legs x (3.1416 x Stirrupbardia x Stirrupbardia / 4) = 2 x (3.1416 x 20 x 20 / 4) = 2 x 314.16 = 628.32 mm^2. (For Example : At Support, S(reqd) = 628.32 x 500 x (2.42 x 1000) / ((22015.000 - 21999.860) x 1000) = 50214.903 ) At D, S(reqd) = 628.32 x 500 x (2.12 x 1000) / ((28908.000 - 21925.967) x 1000) = 95.390 ) At L/8, S(reqd) = 628.32 x 500 x (1.82 x 1000) / ((28908.000 - 22033.447) x 1000) = 83.172 ) At L/4, S(reqd) = 628.32 x 500 x (1.52 x 1000) / ((14912.000 - 22463.368) x 1000) = (Nominal) ) At 3L/8, S(reqd) = 628.32 x 500 x (1.22 x 1000) / ((14747.000 - 22826.114) x 1000) = (Nominal) ) At L/2, S(reqd) = 628.32 x 500 x (0.92 x 1000) / ((22015.000 - 23329.928) x 1000) = (Nominal) ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =22015.00 /(2.95 x √(50.000) x (17500.00 x 1000) = 0.060 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.3 - Design for Shear Force -----------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(m) from left (m) (m) (m) Area(sq-m) (kN) (kN) (mm) (mm) from formula(mm) -----------------------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 0.920 3.473 22015.000 23329.928 0.060 (Nominal) (Nominal) 3L/8 37.50 12.50 1.300 1.220 3.398 14747.000 22826.114 0.040 (Nominal) (Nominal) L/4 25.00 25.00 1.600 1.520 3.344 14912.000 22463.368 0.041 (Nominal) (Nominal) L/8 12.50 37.50 1.900 1.820 3.280 28908.000 22033.447 0.079 83.172 83 D 2.5 47.50 2.200 2.120 3.264 28908.000 21925.967 0.079 95.390 95 (L) Support 0.00 50.00 2.500 2.420 3.275 22015.000 21999.860 0.060 50214.903 50215 (R) Support 0.00 50.00 2.500 2.420 3.275 22015.000 21999.860 0.060 50214.903 50215 D 2.5 52.50 2.200 2.120 3.264 28908.000 21925.967 0.079 95.390 95 L/8 12.50 62.50 1.900 1.820 3.280 28908.000 22033.447 0.079 83.172 83 L/4 25.00 75.00 1.600 1.520 3.344 14912.000 22463.368 0.041 (Nominal) (Nominal) 3L/8 37.50 87.50 1.300 1.220 3.398 14747.000 22826.114 0.040 (Nominal) (Nominal) L/2 50.00 100.00 1.000 0.920 3.473 22015.000 23329.928 0.060 (Nominal) (Nominal) -----------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (83 + 95 + / 2 = 89.000 mm = 8.900 cm = 9 cm OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 89 x 2 = 178 mm = 18 cm STEP 2: FLEXURAL DESIGN OF BOX GIRDER. For doubly reinforced beams, d < d(reqd); i.e., M > Mc As1 = M/(fs x j x d) f'c = 50 ksi (27.5 MPa) fc = 0.4 x f'c = 0.4 x 50 = 20 ksi R = 0.5 x (fc x k x j) = 0.5 x (50.000 x 0.783 x 0.739) = 5.784 ksi (From 2nd Page of this report). R = 5.784 ksi = 5.784 x 1000 = 5784.50 ksf b = 17.5 m d = 2.42 m Mc = Rbd^2 kN-m. (For Example: At Support, R = 5784.499, b = 17.500 m, d = 2.420 m, Mc = (5784.499 x 17.500 x 2.420^2) = 592835.955 kN-m) (i) The moment is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 182460.000 kN-m, MLL+ = 44360.000 kN-m, Mc = 592835.955 kN-m, M+(Design) = (182460.000 + 44360.000) - 592835.955 = -366015.955 kN-m) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kN-m, MLL- = 0.000 kN-m, Mc = 592835.955 kN-m, M-(Design) = (0.000 kN-m + 0.000 kN-m) - 592835.955 kN-m = -592835.955 kN-m) (ii) The required steel area (As) at top and bottom, fs = 500 ksi j = 0.739 (From 2nd Page of this report). d = 2.42 ft d' = 0.04 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc)/(fs x j x d) m^2 (For Example: At Support, Mc = 592835.955 kN-m, fs = 500.000 N/mm^2, j = 0.739, d = 2.420 m, As1 = (592835.955)/(500.000 x 1000 x 0.739 x 2.420) = 0.663 m^2) As2+ = (M+(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M+(Design) = -366015.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2+ = (-366015.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.308 m^2) As2- = (M-(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M-(Design) = -592835.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2- = (-592835.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.498 m^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) m^2 (For Example: At Support, As+ = (As1) + (As2+) = 0.663 + -0.308 = 0.355 m^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 0.663 + -0.498 = 0.165 m^2) As = (As+) + (As-) m^2 (For Example: At Support, As = 0.355 + (0.165) = 0.520 m^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 m Table 1.4 Design for Bending Moment --------------------------------------------------------------------------------------------------------------------------------------------- Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left (m) (m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (m^2) (kN-m) (m^2) (m^2) --------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 0.92 85680.000 140660.000 0.000 33250.000 0.000 88230.000 0.453 -85680.000 0.057 0.510 E(3L/8) 12.50 1.22 150668.847 68200.000 0.000 24840.000 0.000 -57628.847 0.236 -150668.847 0.079 0.315 F(L/4) 37.50 1.52 233878.866 119820.000 0.000 18470.000 0.000 -95588.866 0.287 -233878.866 0.100 0.387 G(L/8) 37.50 1.82 335310.057 149350.000 0.000 23960.000 0.000 -162000.057 0.316 -335310.057 0.122 0.438 H(D) 47.50 2.12 454962.420 98530.000 0.000 16400.000 0.000 -340032.420 0.254 -454962.420 0.143 0.397 I(L) Support 50.00 2.42 592835.955 182460.000 0.000 44360.000 0.000 -366015.955 0.355 -592835.955 0.165 0.520 I(R) Support 50.00 2.42 592835.955 182460.000 0.000 44360.000 0.000 -366015.955 0.355 -592835.955 0.165 0.520 J(D) 52.50 2.12 454962.420 98530.000 0.000 16400.000 0.000 -340032.420 0.254 -454962.420 0.143 0.397 K(L/8) 62.50 1.82 335310.057 149350.000 0.000 23960.000 0.000 -162000.057 0.316 -335310.057 0.122 0.438 L(L/4) 75.00 1.52 233878.866 119820.000 0.000 18470.000 0.000 -95588.866 0.219 -233878.866 0.032 0.250 M(3L/8) 87.50 1.22 150668.847 68200.000 0.000 24840.000 0.000 -57628.847 0.236 -150668.847 0.079 0.315 N(L/2) 100.00 0.92 85680.000 140660.000 0.000 33250.000 0.000 88230.000 0.453 -85680.000 0.057 0.510 --------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 0.520 m^2 = 519981.223 mm^2 By using Reinforcement Bars of Diameter = 32.000 mm Cross Section Area of each bar = Pi x d^2 / 4 = 3.1416 x Longbardia^2 / 4 = 3.1416 x 32 ^2 / 4 = 804.250 mm^2 Therefore total Number of reinforcement bars = 519981 /804 = 647 Nos. Referring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: DW = 17.5 m C1 = 1.5 m C2 = 0 m Iw = 0.7 m SW = DW - 2 x (C1 + C2 + Iw) = 17.500 - 2 x (1.5 + 0 + 0.7) = 13.100 m D = h = 2.5 m Box width at top = width = 13.100 m., Box width at bottom = bottomwidth = SW = 13.100 m., Approx. height of vertical walls = 2.5 m Number of vertical walls = number of cells + 1 = 1 + 1 = 2. By considering 1.5 m tentative cover on either side, Perimeter of box at support = Perimeter = (17.500 - 2 x 0.05) + (13.100 - 2 x 0.05) + 2 x (2.5 - 2 x 0.05) = 17.400 + 13.000 + 4.800 = 35.2 m Providing long Reinforcement bars of diameter 32 mm, all around the box, in two layers, Total length = 2 x perimeter = 2 x 35.200 m = 70.400 m. The spacing of long reinforcement bars = 70.400 x 1000/646.542 = 108.887 mm. = 109 mm. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged #10 stirrups are used as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * ************************************* Design Report on Normal Analysis (Multi-cell IS / IRC) ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in IS / IRC * * * * Date 02.08.2023 AT 17:48:24 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Website: www.techsoftglobal.com Multi-Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Multi-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in IS / IRC * * * * Date 02.08.2023 AT 17:48:24 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 100 m Bridge Width = Wbridge = 17.5 m Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15 m Slab thickness = t = 0.2 m, Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, n = 9 bb = 1 Clear Cover = cc = 0.040 m Unit weight of Concrete = w = 2.4 Tons/Cum For Slab Bar Diameter = Slabbardia = 10 mm. Loads: Wearing Surface = Lw = 0.0014 MPa Material Properties: f'c = 50 MPa fs = 500 MPa For Shear Design: Stirrups Legs = Legs = 2 Provide Bar Diameter = Stirrupbardia = 20 mm For Flexural Design: Provide Main Long Bar Diameter = Longbardia = 32 mm NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Girders. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the 'Hammer Head' and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using 'Cantilever Form Traveler' or CFT. (Analysis and design have considered sections From support to 'D', 'D' to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 17.5 m Number of girders = N = 6 Width of each girder = b = 15 m Clear span between girders = S = [B - (Nxb)/(N-1)] = [(17.5 - (6x15)/(6-1)] = -14.5 m The c/c distance between girders = GC = c + b = -14.5 + 15 = 0.5 m Unit weight of Concrete = w = 2.4 Tons/Cum Slab thickness = t = 0.2 m Slab Uniformly Distributed Load = w1 = t x w = 0.2 x 2.4 = 0.48 MPa Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, Total UDL = wDL = w1 + w2 = 0.48+0.0014 =0.4814 MPa = 0.4814/1000 ksf = 0.000 MPa Dead-load moment = MDL = wDL x S^2/10 = 0.0004814 x -14.5^2/.10 = 0.010 kN-m Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(-14.5+2)/32] x 16 = -5 k kN-m Impact factor = I = 50/(S+125) = 0.452 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = -5 x 0.3 = -1.500 kN-m Total moment = MT = MDL + MLL + MIMP = (0.010 + -5 + -1.5) = -6.490 kN-m For design = f'c = 50 MPa fc = 0.4 x f'c = 0.4 x 50 = 20 N/mm^2 n = 9 k = n /(n + f'c / fc) = 9 / (9 + 50 / 20) = 20.000, j = 1 - k / 3 = 1 – 0.783 / 3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (20 x 0.783 x 0.739) = 5.784 ksi bb = 1 d reqd = √(MT/R/bb) = √(-6.490 / 5.784 / 1) = NaN mm Clear Cover = cc = 0.040 m d = (t - cc) = 0.2 - 0.04 = 0.16 m If (d < d reqd) d = d req d =0.16 mm^2 Slab thickness = d + cc = 0.16 + 0.04 = 0.2 m. For design = fs = 500 Mpa Required reinforcement, As = MT / (fs x j x d) = -6.490 / (500 x 0.739 x 0.16) = -0.110 mm^2 Provide Bar Diamete = 20 Spacing 120 m c/c, As' = 20.000 x 2.00 = 40.00 mm^2 Also, 2.2/ √S = 2.2/√-14.5 = NaN > 0.67 Distribution steel, As-dist = 40.000 x As = 40.000 x -0.110 = -4.390 mm^2 As(dist) per c/c span = GC x As = 0.5 x -4.390 mm^2 = -2.195 mm^2 Provide Bar Diameter = Slabbardia = 10 mm Numbers in clear span = 7, As' =10 x 120 = 1200 mm^2. The variation is symmetric about 'I'. If the girder depths at 'D' and 'N' are both 40 (L/2 in m) and that at 'I' is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (m) from left (m) 'D'(m) (kN) ( kN) (kN) (kN-m) (kN-m) (kN-m) ---------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 19540.000 9946.000 29486.000 170400.000 77720.000 248120.000 (3L/8) 37.50 12.50 1.300 11120.000 5032.000 16152.000 104600.000-45080.000 59520.000 (L/4) 25.00 25.00 1.600 8298.000 3478.000 11776.000 70270.000-29620.000 40650.000 (L/8) 12.50 37.50 1.900 15850.000 6448.000 22298.000 102700.000-43480.000 59220.000 (D) 2.5 47.50 2.200 16520.000 7610.000 24130.000 93720.000 41280.000 135000.000 (L)(Support) 0.00 50.00 2.500 19540.000 9946.000 29486.000 217100.000102500.000 319600.000 (R)(Support) 0.00 50.00 2.500 19540.000 9946.000 29486.000 217100.000102500.000 319600.000 (D) 2.5 52.50 2.200 16520.000 7610.000 24130.000 93720.000 41280.000 135000.000 (L/8) 12.50 62.50 1.900 15850.000 6448.000 22298.000 102700.000-43480.000 59220.000 (L/4) 25.00 75.00 1.600 8298.000 3478.000 11776.000 70270.000-29620.000 40650.000 (3L/8) 37.50 87.50 1.300 11120.000 5032.000 16152.000 104600.000-45080.000 59520.000 (L/2) 50.00 100.00 1.000 19540.000 9946.000 29486.000 170400.000 77720.000 248120.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 0.2 m, (At 'L/2', Span L1) 0 m, (At '3L/8', Span L1) 1.5 m, (At 'L/4', Span L1) 0.2 m, (At 'L/8', Span L1) 17.500 m, (At depth 'D', Span L1) 2.5 m, (At support) 17.500 m, (At depth 'D', Span L2) 0.2 m, (At 'L/8', Span L2) 1.5 m, (At 'L/4', Span L2) 0 m, (At '3L/8', Span L2) 0.2 m, (At 'L/2', Span L2) Using the analysis of the girder the following results are obtained. STEP 1: SHEAR DESIGN OF BOX GIRDER. Combination of Dead and Live Loads The dead load and (live load + Impact) shear forces and bending moments calculated earlier at various sections of the bridge are now combined to obtain the design (maximum positive and/or negative) shear forces and bending moments. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(m) Area(m) (kN) (kN) (kN) (kN-m) (kN-m) (kN-m) (kN-m) ----------------------------------------------------------------------------------------------------------------------------L/2 50.00 3.46 29486.000 9774.000 39260.000 248120.000 0.000 74380.000 0.000 3L/8 37.50 3.42 16152.000 5010.000 21162.000 59520.000 0.000 46360.000 0.000 L/4 25.00 3.40 11776.000 3504.000 15280.000 40650.000 0.000 29640.000 0.000 L/8 12.50 3.57 22298.000 6895.000 29193.000 59220.000 0.000 43800.000 0.000 D 2.5 3.77 24130.000 7434.000 31564.000 135000.000 0.000 40300.000 0.000 (L)(Support) 0.00 5.20 29486.000 9774.000 39260.000 319600.000 0.000 97810.000 0.000 (R)(Support) 0.00 5.20 29486.000 9774.000 39260.000 319600.000 0.000 97810.000 0.000 D 2.5 3.77 24130.000 7434.000 31564.000 135000.000 0.000 40300.000 0.000 L/8 12.50 3.57 22298.000 6895.000 29193.000 59220.000 0.000 43800.000 0.000 L/4 25.00 3.40 11776.000 3504.000 15280.000 40650.000 0.000 29640.000 0.000 3L/8 37.50 3.42 16152.000 5010.000 21162.000 59520.000 0.000 46360.000 0.000 L/2 50.00 3.46 29486.000 9774.000 39260.000 248120.000 0.000 74380.000 0.000 ----------------------------------------------------------------------------------------------------------------------------- THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(50) x Av = 6.718 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 6.718 x 5.204 x 10^6 = 34.958 x 10^6 N. = 34.958 At D, Vc = 6.718 x 3.769 x 10^6 = 25.318 x 10^6 N. = 25.318 x At L/8, Vc = 6.718 x 3.568 x 10^6 = 23.968 x 10^6 N. = 23.968 x At L/4, Vc = 6.718 x 3.396 x 10^6 = 22.813 x 10^6 N. = 22.813 x At 3L/8, Vc = 6.718 x 3.418 x 10^6 = 22.960 x 10^6 N. = 22.960 x At L/2, Vc = 6.718 x 3.463 x 10^6 = 23.263 x 10^6 N. = 23.263 x x 10^3 kN = 34957.945 kN. 10^3 kN = 25318.312 kN. 10^3 kN = 23968.091 kN. 10^3 kN = 22812.679 kN. 10^3 kN = 22960.464 kN. 10^3 kN = 23262.752 kN. The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 2.500 m, cc = 0.040 m, d = h – 2 x cc = 2.500 - 2 x 0.040 = 2.420 m, fs = 500 Mpa. If 2-legged (Legs=2), 20 mm diameter (Stirrupbardia = 20) stirrups are used, As = Legs x (3.1416 x Stirrupbardia x Stirrupbardia / 4) = 2 x (3.1416 x 20 x 20 / 4) = 2 x 314.16 = 628.32 mm^2. (For Example : At Support, S(reqd) = 628.32 x 500 x (2.42 x 1000) / ((39260.000 - 34957.945) x 1000) = 176.722 ) At D, S(reqd) = 628.32 x 500 x (2.12 x 1000) / ((31564.000 - 25318.312) x 1000) = 106.637 ) At L/8, S(reqd) = 628.32 x 500 x (1.82 x 1000) / ((29193.000 - 23968.091) x 1000) = 109.432 ) At L/4, S(reqd) = 628.32 x 500 x (1.52 x 1000) / ((15280.000 - 22812.679) x 1000) = (Nominal) ) At 3L/8, S(reqd) = 628.32 x 500 x (1.22 x 1000) / ((21162.000 - 22960.464) x 1000) = (Nominal) ) At L/2, S(reqd) = 628.32 x 500 x (0.92 x 1000) / ((39260.000 - 23262.752) x 1000) = 18.067 ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =39260.00 /(2.95 x √(50.000) x (17500.00 x 1000) = 0.108 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.3 - Design for Shear Force -----------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(m) from left (m) (m) (m) Area(sq-m) (kN) (kN) (mm) (mm) from formula(mm) -----------------------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 0.920 3.463 39260.000 23262.752 0.108 18.067 18 3L/8 37.50 12.50 1.300 1.220 3.418 21162.000 22960.464 0.058 (Nominal) (Nominal) L/4 25.00 25.00 1.600 1.520 3.396 15280.000 22812.679 0.042 (Nominal) (Nominal) L/8 12.50 37.50 1.900 1.820 3.568 29193.000 23968.091 0.080 109.432 109 D 2.5 47.50 2.200 2.120 3.769 31564.000 25318.312 0.086 106.637 107 (L) Support 0.00 50.00 2.500 2.420 5.204 39260.000 34957.945 0.108 176.722 177 (R) Support 0.00 50.00 2.500 2.420 5.204 39260.000 34957.945 0.108 176.722 177 D 2.5 52.50 2.200 2.120 3.769 31564.000 25318.312 0.086 106.637 107 L/8 12.50 62.50 1.900 1.820 3.568 29193.000 23968.091 0.080 109.432 109 L/4 25.00 75.00 1.600 1.520 3.396 15280.000 22812.679 0.042 (Nominal) (Nominal) 3L/8 37.50 87.50 1.300 1.220 3.418 21162.000 22960.464 0.058 (Nominal) (Nominal) L/2 50.00 100.00 1.000 0.920 3.463 39260.000 23262.752 0.108 18.067 18 -----------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (18 + 109 + 107 + 177 / 4 = 102.750 mm = 10.275 cm = 10 cm OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 102.75 x 2 = 205.5 mm = 21 cm STEP 2: FLEXURAL DESIGN OF BOX GIRDER. For doubly reinforced beams, d < d(reqd); i.e., M > Mc As1 = M/(fs x j x d) f'c = 50 ksi (27.5 MPa) fc = 0.4 x f'c = 0.4 x 50 = 20 ksi R = 0.5 x (fc x k x j) = 0.5 x (50.000 x 0.783 x 0.739) = 5.784 ksi (From 2nd Page of this report). R = 5.784 ksi = 5.784 x 1000 = 5784.50 ksf b = 17.5 m d = 2.42 m Mc = Rbd^2 kN-m. (For Example: At Support, R = 5784.499, b = 17.500 m, d = 2.420 m, Mc = (5784.499 x 17.500 x 2.420^2) = 592835.955 kN-m) (i) The moment is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 319600.000 kN-m, MLL+ = 97810.000 kN-m, Mc = 592835.955 kN-m, M+(Design) = (319600.000 + 97810.000) - 592835.955 = -175425.955 kN-m) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kN-m, MLL- = 0.000 kN-m, Mc = 592835.955 kN-m, M-(Design) = (0.000 kN-m + 0.000 kN-m) - 592835.955 kN-m = -592835.955 kN-m) (ii) The required steel area (As) at top and bottom, fs = 500 ksi j = 0.739 (From 2nd Page of this report). d = 2.42 m d' = 0.04 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc)/(fs x j x d) m^2 (For Example: At Support, Mc = 592835.955 kN-m, fs = 500.000 N/mm^2, j = 0.739, d = 2.420 m, As1 = (592835.955)/(500.000 x 1000 x 0.739 x 2.420) = 0.663 m^2) As2+ = (M+(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M+(Design) = -175425.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2+ = (-175425.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.147 m^2) As2- = (M-(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M-(Design) = -592835.955 kN-m, fs = 500.000 ksi, d = 2.420 m, d' = 0.040 m, As2- = (-592835.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.498 m^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) m^2 (For Example: At Support, As+ = (As1) + (As2+) = 0.663 + -0.147 = 0.515 m^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 0.663 + -0.498 = 0.165 m^2) As = (As+) + (As-) m^2 (For Example: At Support, As = 0.515 + (0.165) = 0.680 m^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 m Table 1.4 Design for Bending Moment ----------------------------------------------------------------------------------------------------------------------------------------------Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left (m) (m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (m^2) (kN-m) (m^2) (m^2) ----------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 0.92 85680.000 248120.000 0.000 74380.000 0.000 236820.000 0.790 -85680.000 0.057 0.848 E(3L/8) 12.50 1.22 150668.847 59520.000 0.000 46360.000 0.000 -44788.847 0.258 -150668.847 0.079 0.337 F(L/4) 37.50 1.52 233878.866 40650.000 0.000 29640.000 0.000 -163588.866 0.195 -233878.866 0.100 0.296 G(L/8) 37.50 1.82 335310.057 59220.000 0.000 43800.000 0.000 -232290.057 0.238 -335310.057 0.122 0.359 H(D) 47.50 2.12 454962.420 135000.000 0.000 40300.000 0.000 -279662.420 0.312 -454962.420 0.143 0.455 I(L) Support 50.00 2.42 592835.955 319600.000 0.000 97810.000 0.000 -175425.955 0.515 -592835.955 0.165 0.680 I(R) Support 50.00 2.42 592835.955 319600.000 0.000 97810.000 0.000 -175425.955 0.515 -592835.955 0.165 0.680 J(D) 52.50 2.12 454962.420 135000.000 0.000 40300.000 0.000 -279662.420 0.312 -454962.420 0.143 0.455 K(L/8) 62.50 1.82 335310.057 59220.000 0.000 43800.000 0.000 -232290.057 0.238 -335310.057 0.122 0.359 L(L/4) 75.00 1.52 233878.866 40650.000 0.000 29640.000 0.000 -163588.866 0.127 -233878.866 0.032 0.158 M(3L/8) 87.50 1.22 150668.847 59520.000 0.000 46360.000 0.000 -44788.847 0.258 -150668.847 0.079 0.337 N(L/2) 100.00 0.92 85680.000 248120.000 0.000 74380.000 0.000 236820.000 0.790 -85680.000 0.057 0.848 ----------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 0.680 m^2 = 680140.887 mm^2 By using Reinforcement Bars of Diameter = 32.000 mm Cross Section Area of each bar = Pi x d^2 / 4 = 3.1416 x Longbardia^2 / 4 = 3.1416 x 32 ^2 / 4 = 804.250 mm^2 Therefore total Number of reinforcement bars = 680141 /804 = 846 Nos. Referring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: b1 = 17.500 m b6 = 0.800 m b7 = 0.546 m b8 = b1 - 2 x (b6 + b7) = 17.500 - 2 x (0.800 + 0.546) = 14.808 m d4 = h = 2.5 m Box width at top = width = 14.808 m., Box width at bottom = bottomwidth = SW = 14.808 m., Approx. height of vertical walls = 0.303 m Number of vertical walls = number of cells + 1 = 5 + 1 = 6. By considering 1.5 m tentative cover on either side, Perimeter of box at support = Perimeter = (17.500 - 2 x 0.05) + (14.808 - 2 x 0.05) + 6 x (2.5 - 2 x 0.05) = 17.400 + 14.708 + 14.400 = 46.508 m Providing long Reinforcement bars of diameter 32 mm, all around the box, in two layers, Total length = 2 x perimeter = 2 x 46.508 m = 93.016 m. The spacing of long reinforcement bars = 93.016 x 1000/845.684 = 109.989 mm. = 110 mm. = 11 cm. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged #10 stirrups are used as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * ************************************* Design Repo Report on Normal Analysis (Single-cell IS / IRC) *********** ******************************************* * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Si ingle-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in IS / IRC * * * * Date 03.08.2023 AT 15:09:28 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * *********** ******************************************* W Website: www.techsoftglobal.com Single-C Cell PSC Box-Girder Cross-Section ***************************************************** * * * * * ASTRA Pro * * * * Design Report of Balanced Cantilever Bridge * * with Single-Cell PSC Box-Girder Cross-Section * * * * DESIGN ON ANALYSIS RESULTS * * in IS / IRC * * * * Date 03.08.2023 AT 15:09:28 * * * * INTRODUCED BY * * TECHSOFT ENGINEERING SERVICES * * * * * ***************************************************** Design Data General Superstructure Data: Bridge Span = Span = 100 m Bridge Width = Wbridge = 17.5 m Nos. of PSC I-Girders at start and end of Bridge = Ngirders = 6 Width of each girder = Wgirders = 15 m Slab thickness = t = 0.2 m, Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, n = 9 bb = 1 Clear Cover = cc = 0.040 m Unit weight of Concrete = w = 2.4 Tons/Cum For Slab Bar Diameter = Slabbardia = 10 mm. Loads: Wearing Surface = Lw = 0.0014 MPa Material Properties: f'c = 50 MPa fs = 500 MPa For Shear Design: Stirrups Legs = Legs = 2 Provide Bar Diameter = Stirrupbardia = 20 mm For Flexural Design: Provide Main Long Bar Diameter = Longbardia = 32 mm NOTE: The first and the last spans from abutment to the nearest Pier, the deck structure is treated as RCC Slab resting on I-Girders. Next, from this first Pier the next span up to the second Pier and all subsequent spans up to the span before the end span will be constructed as Balanced Cantilever Bridge, with Pre-stressed concrete cast-in-place segmental box girder on either side of the pier up to middle of each span. The general arrangement sample drawings may be referred for better understanding. The segment just on the pier is the 'Hammer Head' and segments are cast as one on either side to maintain the balance of the load on either side of the pier. This way one segment is cast on either side, up to the middle of either side span. The reinforcements are continuous through all the segments of the box girder and after casting and setting each segment. This is constructed by using 'Cantilever Form Traveler' or CFT. (Analysis and design have considered sections From support to 'D', 'D' to L/8. L/8 to L/4, L/4 to 3/L/8, and 3L/8 to L/2, which is the mid-span, THIS to be remembered that these all are segments, not necessarily the sections chosen for casting suitable to the CFT, as mentioned above) DESIGN OF RCC SLAB: Bridge width = B = 17.5 m Number of girders = N = 6 Width of each girder = b = 15 m Clear span between girders = S = [B - (Nxb)/(N-1)] = [(17.5 - (6x15)/(6-1)] = -14.5 m The c/c distance between girders = GC = c + b = -14.5 + 15 = 0.5 m Unit weight of Concrete = w = 2.4 Tons/Cum Slab thickness = t = 0.2 m Slab Uniformly Distributed Load = w1 = t x w = 0.2 x 2.4 = 0.48 MPa Wearing Surface Uniformly Distributed Load = w2 = 0.0014 MPa, Total UDL = wDL = w1 + w2 = 0.48+0.0014 =0.4814 MPa = 0.4814/1000 ksf = 0.000 MPa Dead-load moment = MDL = wDL x S^2/10 = 0.0004814 x -14.5^2/.10 = 0.010 kN-m Live-load moment = MLL = 0.8 (S+2)/32 x P20 = 0.8 x [(-14.5+2)/32] x 16 = -5 k kN-m Impact factor = I = 50/(S+125) = 0.452 If (I > 0.3), I = 0.3 Impact moment = MIMP = MLL x I = -5 x 0.3 = -1.500 kN-m Total moment = MT = MDL + MLL + MIMP = (0.010 + -5 + -1.5) = -6.490 kN-m For design = f'c = 50 MPa fc = 0.4 x f'c = 0.4 x 50 = 20 N/mm^2 n = 9 k = n /(n + f'c / fc) = 9 / (9 + 50 / 20) = 20.000, j = 1 - k / 3 = 1 – 0.783 / 3) = 0.739 R = 0.5 x (fc x k x j) = 0.5 x (20 x 0.783 x 0.739) = 5.784 ksi bb = 1 d reqd = √(MT/R/bb) = √(-6.490 / 5.784 / 1) = NaN mm Clear Cover = cc = 0.040 m d = (t - cc) = 0.2 - 0.04 = 0.16 m If (d < d reqd) d = d req d =0.16 mm^2 Slab thickness = d + cc = 0.16 + 0.04 = 0.2 m. For design = fs = 500 Mpa Required reinforcement, As = MT / (fs x j x d) = -6.490 / (500 x 0.739 x 0.16) = -0.110 mm^2 Provide Bar Diamete = 20 Spacing 120 m c/c, As' = 20.000 x 2.00 = 40.00 mm^2 Also, 2.2/ √S = 2.2/√-14.5 = NaN > 0.67 Distribution steel, As-dist = 40.000 x As = 40.000 x -0.110 = -4.390 mm^2 As(dist) per c/c span = GC x As = 0.5 x -4.390 mm^2 = -2.195 mm^2 Provide Bar Diameter = Slabbardia = 10 mm Numbers in clear span = 7, As' =10 x 120 = 1200 mm^2. The variation is symmetric about 'I'. If the girder depths at 'D' and 'N' are both 40 (L/2 in m) and that at 'I' is 70 (about 70-80% larger), the depths at the other sections can be calculated easily. The depths of segments at relevant sections (D thru N) are the following: DESIGN OF SEGMENTAL CAST-IN PLACE BOX GIRDER WITH CONTINUOUS REINFORCEMENTS THROUGH SEGMENTS: Table 1.1 - DEAD LOAD SHEAR FORCES AND BENDING MOMENTS OBTAINED FROM ANALYSIS ---------------------------------------------------------------------------------------------------------------------------Section Distance Distance(x) Depth DL SF SIDL SF Total DL SF DL BM SIDL BM Total DL BM (at) from Support (m) from left (m) 'D'(m) (kN) ( kN) (kN) (kN-m) (kN-m) (kN-m) ---------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 12750.000 4817.000 17567.000 103600.000 37060.000 140660.000 (3L/8) 37.50 12.50 1.300 9734.000 2790.000 12524.000 96060.000-27860.000 68200.000 (L/4) 25.00 25.00 1.600 10440.000 2529.000 12969.000 95910.000 23910.000 119820.000 (L/8) 12.50 37.50 1.900 20070.000 4948.000 25018.000 119400.000 29950.000 149350.000 (D) 2.5 47.50 2.200 20070.000 4948.000 25018.000 77520.000 21010.000 98530.000 (L)(Support) 0.00 50.00 2.500 12750.000 4817.000 17567.000 133400.000 49060.000 182460.000 (R)(Support) 0.00 50.00 2.500 12750.000 4817.000 17567.000 133400.000 49060.000 182460.000 (D) 2.5 52.50 2.200 20070.000 4948.000 25018.000 77520.000 21010.000 98530.000 (L/8) 12.50 62.50 1.900 20070.000 4948.000 25018.000 119400.000 29950.000 149350.000 (L/4) 25.00 75.00 1.600 10440.000 2529.000 12969.000 95910.000 23910.000 119820.000 (3L/8) 37.50 87.50 1.300 9734.000 2790.000 12524.000 96060.000-27860.000 68200.000 (L/2) 50.00 100.00 1.000 12750.000 4817.000 17567.000 103600.000 37060.000 140660.000 ---------------------------------------------------------------------------------------------------------------------------Design of BOX Girder hD hE hF hG hH hI hJ hK hL hM hN = = = = = = = = = = = 0.2 m, (At 'L/2', Span L1) 0 m, (At '3L/8', Span L1) 1.5 m, (At 'L/4', Span L1) 0.2 m, (At 'L/8', Span L1) 17.500 m, (At depth 'D', Span L1) 2.5 m, (At support) 17.500 m, (At depth 'D', Span L2) 0.2 m, (At 'L/8', Span L2) 1.5 m, (At 'L/4', Span L2) 0 m, (At '3L/8', Span L2) 0.2 m, (At 'L/2', Span L2) Using the analysis of the girder the following results are obtained. STEP 1: SHEAR DESIGN OF BOX GIRDER. Combination of Dead and Live Loads The dead load and (live load + Impact) shear forces and bending moments calculated earlier at various sections of the bridge are now combined to obtain the design (maximum positive and/or negative) shear forces and bending moments. Table 1.2 – DEAD LOAD AND LIVE LOAD SHEAR FORCE and BENDING MOMENTS ----------------------------------------------------------------------------------------------------------------------------Section Distance Cross Section VDl VLL V(Total) M(DL+) M(DL-) M(LL+) M(LL-) (at) from Support(m) Area(m) (kN) (kN) (kN) (kN-m) (kN-m) (kN-m) (kN-m) ----------------------------------------------------------------------------------------------------------------------------L/2 50.00 3.47 17567.000 4552.000 22119.000 140660.000 0.000 33840.000 0.000 3L/8 37.50 3.40 12524.000 2980.000 15504.000 68200.000 0.000 26140.000 0.000 L/4 25.00 3.34 12969.000 1997.000 14966.000 119820.000 0.000 18480.000 0.000 L/8 12.50 3.28 25018.000 3890.000 28908.000 149350.000 0.000 24970.000 0.000 D 2.5 3.26 25018.000 3890.000 28908.000 98530.000 0.000 20180.000 0.000 (L)(Support) 0.00 3.28 17567.000 4552.000 22119.000 182460.000 0.000 44910.000 0.000 (R)(Support) 0.00 3.28 17567.000 4552.000 22119.000 182460.000 0.000 44910.000 0.000 D 2.5 3.26 25018.000 3890.000 28908.000 98530.000 0.000 20180.000 0.000 L/8 12.50 3.28 25018.000 3890.000 28908.000 149350.000 0.000 24970.000 0.000 L/4 25.00 3.34 12969.000 1997.000 14966.000 119820.000 0.000 18480.000 0.000 3L/8 37.50 3.40 12524.000 2980.000 15504.000 68200.000 0.000 26140.000 0.000 L/2 50.00 3.47 17567.000 4552.000 22119.000 140660.000 0.000 33840.000 0.000 ----------------------------------------------------------------------------------------------------------------------------THE SHEAR DESIGN OF GIRDERS IS PERFORMED BY USING THE CONVENTIONAL SHEAR DESIGN EQUATIONS OF RCC MEMBERS. Vc = 0.95√f'c x Av = 0.95√(50) x Av = 6.718 x Av (For Example : At Support, Shear capacity of the Cross section, At Support Vc = 6.718 x 3.275 x 10^6 = 22.000 x 10^6 N. = 22.000 At D, Vc = 6.718 x 3.264 x 10^6 = 21.926 x 10^6 N. = 21.926 x At L/8, Vc = 6.718 x 3.280 x 10^6 = 22.033 x 10^6 N. = 22.033 x At L/4, Vc = 6.718 x 3.344 x 10^6 = 22.463 x 10^6 N. = 22.463 x At 3L/8, Vc = 6.718 x 3.398 x 10^6 = 22.826 x 10^6 N. = 22.826 x At L/2, Vc = 6.718 x 3.473 x 10^6 = 23.330 x 10^6 N. = 23.330 x x 10^3 kN = 21999.860 kN. 10^3 kN = 21925.967 kN. 10^3 kN = 22033.447 kN. 10^3 kN = 22463.368 kN. 10^3 kN = 22826.114 kN. 10^3 kN = 23329.928 kN. The stirrup spacing is given by the equation S(reqd) = As fs d/(V–Vc) At Support, h = 2.500 m, cc = 0.040 m, d = h – 2 x cc = 2.500 - 2 x 0.040 = 2.420 m, fs = 500 Mpa. If 2-legged (Legs=2), 20 mm diameter (Stirrupbardia = 20) stirrups are used, As = Legs x (3.1416 x Stirrupbardia x Stirrupbardia / 4) = 2 x (3.1416 x 20 x 20 / 4) = 2 x 314.16 = 628.32 mm^2. (For Example : At Support, S(reqd) = 628.32 x 500 x (2.42 x 1000) / ((22119.000 - 21999.860) x 1000) = 6381.278 ) At D, S(reqd) = 628.32 x 500 x (2.12 x 1000) / ((28908.000 - 21925.967) x 1000) = 95.390 ) At L/8, S(reqd) = 628.32 x 500 x (1.82 x 1000) / ((28908.000 - 22033.447) x 1000) = 83.172 ) At L/4, S(reqd) = 628.32 x 500 x (1.52 x 1000) / ((14966.000 - 22463.368) x 1000) = (Nominal) ) At 3L/8, S(reqd) = 628.32 x 500 x (1.22 x 1000) / ((15504.000 - 22826.114) x 1000) = (Nominal) ) At L/2, S(reqd) = 628.32 x 500 x (0.92 x 1000) / ((22119.000 - 23329.928) x 1000) = (Nominal) ) d (reqd) = V/(2.95√f'c b) (For Example :- At Support d (reqd) =22119.00 /(2.95 x √(50.000) x (17500.00 x 1000) = 0.061 mm) where d, Av and V vary from section to section. The calculations are carried out in tabular form and listed below. Table 1.3 - Design for Shear Force -----------------------------------------------------------------------------------------------------------------------------------------Section Distance Distance (X) h d Cross Section V(Design) Vc d(reqd) S(reqd) S(prov) (at) from Support(m) from left (m) (m) (m) Area(sq-m) (kN) (kN) (mm) (mm) from formula(mm) -----------------------------------------------------------------------------------------------------------------------------------------L/2 50.00 0.00 1.000 0.920 3.473 22119.000 23329.928 0.061 (Nominal) (Nominal) 3L/8 37.50 12.50 1.300 1.220 3.398 15504.000 22826.114 0.042 (Nominal) (Nominal) L/4 25.00 25.00 1.600 1.520 3.344 14966.000 22463.368 0.041 (Nominal) (Nominal) L/8 12.50 37.50 1.900 1.820 3.280 28908.000 22033.447 0.079 83.172 83 D 2.5 47.50 2.200 2.120 3.264 28908.000 21925.967 0.079 95.390 95 (L) Support 0.00 50.00 2.500 2.420 3.275 22119.000 21999.860 0.061 6381.278 6381 (R) Support 0.00 50.00 2.500 2.420 3.275 22119.000 21999.860 0.061 6381.278 6381 D 2.5 52.50 2.200 2.120 3.264 28908.000 21925.967 0.079 95.390 95 L/8 12.50 62.50 1.900 1.820 3.280 28908.000 22033.447 0.079 83.172 83 L/4 25.00 75.00 1.600 1.520 3.344 14966.000 22463.368 0.041 (Nominal) (Nominal) 3L/8 37.50 87.50 1.300 1.220 3.398 15504.000 22826.114 0.042 (Nominal) (Nominal) L/2 50.00 100.00 1.000 0.920 3.473 22119.000 23329.928 0.061 (Nominal) (Nominal) -----------------------------------------------------------------------------------------------------------------------------------------By using single Stirrup Loop, From (Support) to (L/2), the Average Stirrup Spacing may be = (83 + 95 ) / 2 = 89.000 mm = 8.900 cm = 9 cm OR, By using double Stirrup Loops (Outer and Inner), From (Support) to (L/2), the Average Spacing may be = 89 x 2 = 178 mm = 18 cm STEP 2: FLEXURAL DESIGN OF BOX GIRDER. For doubly reinforced beams, d < d(reqd); i.e., M > Mc As1 = M/(fs x j x d) f'c = 50 ksi (27.5 MPa) fc = 0.4 x f'c = 0.4 x 50 = 20 ksi R = 0.5 x (fc x k x j) = 0.5 x (50.000 x 0.783 x 0.739) = 5.784 ksi (From 2nd Page of this report). R = 5.784 ksi = 5.784 x 1000 = 5784.50 ksf b = 17.5 ft d = 2.42 ft Mc = Rbd^2 kN-m. (For Example: At Support, R = 5784.499, b = 17.500 ft, d = 2.420 ft, Mc = (5784.499 x 17.500 x 2.420^2) = 592835.955 kN-m) (i) The moment is divided into two parts; i.e., M+(Design) = (MDL+ + MLL+) – Mc. (For Example: At Support, MDL+ = 182460.000 kN-m, MLL+ = 44910.000 kN-m, Mc = 592835.955 kN-m, M+(Design) = (182460.000 + 44910.000) - 592835.955 = -365465.955 kN-m) M-(Design) = (MDL- + MLL-) – Mc. (For Example: At Support, MDL- = 0.000 kN-m, MLL- = 0.000 kN-m, Mc = 592835.955 kN-m, M-(Design) = (0.000 kN-m + 0.000 kN-m) - 592835.955 kN-m = -592835.955 kN-m) (ii) The required steel area (As) at top and bottom, fs = 500 ksi j = 0.739 (From 2nd Page of this report). d = 2.42 ft d' = 0.04 m From 2nd Page of this report: n = 9 k = 0.783 (From 2nd Page of this report) j = 0.739 (From 2nd Page of this report) As1 = (Mc)/(fs x j x d) m^2 (For Example: At Support, Mc = 592835.955 kN-m, fs = 500.000 N/mm^2, j = 0.739, d = 2.420 m, As1 = (592835.955)/(500.000 x 1000 x 0.739 x 2.420) = 0.663 m^2) As2+ = (M+(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M+(Design) = -365465.955 kN-m, fs = 500.000 ksi, d = 2.420 ft, d' = 0.040 ft, As2+ = (-365465.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.307 m^2) As2- = (M-(Design)) / (fs x (d – d')) m^2 (For Example: At Support, M-(Design) = -592835.955 kN-m, fs = 500.000 ksi, d = 2.420 ft, d' = 0.040 ft, As2- = (-592835.955) / (500.000 x 1000 x (2.420 - 0.040)) = -0.498 m^2) The required steel area (As) at top and bottom is given by, As+ = (As1) + (As2+) m^2 (For Example: At Support, As+ = (As1) + (As2+) = 0.663 + -0.307 = 0.356 m^2) As- = (As1) + (As2-) m^2 (For Example: At Support, As- =(As1) + (As2+) = 0.663 + -0.498 = 0.165 m^2) As = (As+) + (As-) m^2 (For Example: At Support, As = 0.356 + (0.165) = 0.520 m^2) From Table 2.3, For #10 bars, Area = 1.27 Development Length = 0.04 x Area x 40/sqrt(0.03) x 1.4 = 0.04 x 1.27 x 40/sqrt(0.03) x 1.4 = 51.94 m Table 1.4 Design for Bending Moment --------------------------------------------------------------------------------------------------------------------------------------------- Section Distance x d Mc M(DL+) M(DL-) M(LL+) M(LL-) M+(design) As+ M-(design) AsAs (at) from left (m) (m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (kN-m) (m^2) (kN-m) (m^2) (m^2) --------------------------------------------------------------------------------------------------------------------------------------------D(L/2) 0.00 0.92 85680.000 140660.000 0.000 33840.000 0.000 88820.000 0.454 -85680.000 0.057 0.511 E(3L/8) 12.50 1.22 150668.847 68200.000 0.000 26140.000 0.000 -56328.847 0.239 -150668.847 0.079 0.318 F(L/4) 37.50 1.52 233878.866 119820.000 0.000 18480.000 0.000 -95578.866 0.287 -233878.866 0.100 0.387 G(L/8) 37.50 1.82 335310.057 149350.000 0.000 24970.000 0.000 -160990.057 0.318 -335310.057 0.122 0.439 H(D) 47.50 2.12 454962.420 98530.000 0.000 20180.000 0.000 -336252.420 0.257 -454962.420 0.143 0.401 I(L) Support 50.00 2.42 592835.955 182460.000 0.000 44910.000 0.000 -365465.955 0.356 -592835.955 0.165 0.520 I(R) Support 50.00 2.42 592835.955 182460.000 0.000 44910.000 0.000 -365465.955 0.356 -592835.955 0.165 0.520 J(D) 52.50 2.12 454962.420 98530.000 0.000 20180.000 0.000 -336252.420 0.257 -454962.420 0.143 0.401 K(L/8) 62.50 1.82 335310.057 149350.000 0.000 24970.000 0.000 -160990.057 0.318 -335310.057 0.122 0.439 L(L/4) 75.00 1.52 233878.866 119820.000 0.000 18480.000 0.000 -95578.866 0.219 -233878.866 0.032 0.250 M(3L/8) 87.50 1.22 150668.847 68200.000 0.000 26140.000 0.000 -56328.847 0.239 -150668.847 0.079 0.318 N(L/2) 100.00 0.92 85680.000 140660.000 0.000 33840.000 0.000 88820.000 0.454 -85680.000 0.057 0.511 --------------------------------------------------------------------------------------------------------------------------------------------Note: Distribution of Longitudinal Reinforcement Bars: Only at support section, the calculation is described below, by referring to the above Table 1.4, this calculations are to be done at other sections similarly. Requirements for longitudinal Steel Reinforcements = As = 0.520 m^2 = 520443.408 mm^2 By using Reinforcement Bars of Diameter = 32.000 mm Cross Section Area of each bar = Pi x d^2 / 4 = 3.1416 x Longbardia^2 / 4 = 3.1416 x 32 ^2 / 4 = 804.250 mm^2 Therefore total Number of reinforcement bars = 520443 /804 = 647 Nos. Referring to Cross Section Tab, Cross Section data and Figure, we have the following dimensions as given below: DW = 17.5 m C1 = 1.5 m C2 = 0 m Iw = 0.7 m SW = DW - 2 x (C1 + C2 + Iw) = 17.500 - 2 x (1.5 + 0 + 0.7) = 13.100 m D = h = 2.5 m Box width at top = width = 13.100 m., Box width at bottom = bottomwidth = SW = 13.100 m., Approx. height of vertical walls = 2.5 m Number of vertical walls = number of cells + 1 = 1 + 1 = 2. By considering 1.5 m tentative cover on either side, Perimeter of box at support = Perimeter = (17.500 - 2 x 0.05) + (13.100 - 2 x 0.05) + 2 x (2.5 - 2 x 0.05) = 17.400 + 13.000 + 4.800 = 35.2 m Providing long Reinforcement bars of diameter 32 mm, all around the box, in two layers, Total length = 2 x perimeter = 2 x 35.200 m = 70.400 m. The spacing of long reinforcement bars = 70.400 x 1000/647.117 = 108.790 mm. = 109 mm. = 10.9 cm. These long bars will be continuous through the segments, inside each of two (Outer and Inner) loops of 2-legged #10 stirrups are used as Provided in shear design. (A) Analysis (i) Reducing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will reduce Shear Force and Bending Moments for Dead Load. (ii) Increasing of thickness of Top Slab, Bottom Slab and Vertical/inclined walls, will increase Shear (Vc) and Moment (Mc) Capacities of section. (iii) Increasing of Increment of moving Load (suggested range 0.2 to 2 metres), will reduce Shear Force and Bending Moments for Live Load. (B) Design (i) (ii) Increasing of the Span and Overall Width, will increase will increase Shear Force (V) and Bending Moment (M). Increasing the Grades of concrete and Steel, will increase Shear (Vc) and Moment (Mc) Capacities of section. Effects of (A) and (B): (i) Reduction in Shear Force and Bending Moments will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. (ii) Increase in Shear (Vc) and Moment (Mc) Capacities of section, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively, too high shear capacity may result ‘Nominal’ Shear Reinforcement spacing. (iii) Increase in Reinforcement Bar Diameters for Stirrups and Long Main Bars, will increase the spacing of Shear (Stirrups) and Flexural Reinforcements, respectively. ************************************* * End of Design * *************************************