CN113482240B - Concrete column adopting prefabricated angle steel lattice permanent formwork and manufacturing method thereof - Google Patents

Abstract

The invention discloses a prefabricated angle steel lattice permanent formwork concrete column and a manufacturing method thereof, which solve the problem that construction quality is difficult to control when the concrete column is bound and poured on site during construction. Meanwhile, the invention is beneficial to simplifying the construction process, reducing the waste of personnel and materials and improving the construction efficiency as one of the assembly type construction methods. The concrete column permanent formwork is prefabricated by angle steel, batten plates and ultra-high-strength concrete (UHPC) which are arranged at four corners. A part of bearing capacity is provided for the column structure, and the model of concrete can be selected according to the design bearing capacity of the component in the subsequent assembly type pouring; if necessary, a reinforcement cage may also be provided internally. The connection method of the prefabricated angle steel lattice permanent formwork concrete columns is only suitable for multi-storey building structures at present. And the prefabricated steel structural members with stiffening ribs are selected and connected with reserved angle steels in the upper and lower column permanent templates through high-strength bolts.

Description

A concrete column using prefabricated angle steel lattice permanent formwork and its manufacturing method

technical field

The invention relates to the technical field of composite columns, in particular to a novel concrete column using a prefabricated angle steel lattice structure permanent formwork and a manufacturing method thereof.

Background technique

With the development of my country's economic level and construction technology, my country's construction industry has entered a period of transformation and upgrading. The modernization of the construction industry has highlighted the inevitability and importance of the structural reform and development of the supply side of the construction industry from many aspects such as technology and industry; among them, prefabricated The selection and implementation of the construction mode of the building prefabricated component production base has important research and practical significance for the rapid advancement and implementation of building industrialization.

As far as formwork engineering is concerned, traditional formwork is mainly wood formwork and steel formwork. Although it can meet the construction needs, it is very cumbersome to support and disassemble the formwork. According to statistics, in the construction of cast-in-place concrete structures, every ^1m2 of concrete engineering , the amount of formwork is as high as 4 to 5m ² , and its engineering cost accounts for about 1/3 of the cost of cast-in-place concrete structures, and the labor consumption and construction period account for about half; Greatly reduce the demand for formwork materials such as wood, and simplify construction procedures such as on-site formwork removal and tying steel bars; prefabricated steel components used for column-to-column connections can also improve work efficiency on the construction site and ensure connection quality, which is in line with today's green construction environmental requirements.

The new type of built-in angle steel concrete column structure refers to replacing the longitudinal reinforcement in the ordinary concrete column structure with the rigid angle steel, and then replacing the stirrup in the ordinary concrete column structure with the steel plate hoop welded to the longitudinal angle steel, thus forming a space steel skeleton. A new structure formed by combining with concrete; the advantage of this structure is that the steel skeleton structure inside the concrete column is relatively simple and it is convenient for the setting of embedded parts; at the same time, the steel skeleton can be prefabricated in the factory, which can effectively reduce the on-site construction and binding steel bars test pieces, and improve the overall quality of the component.

Ultra-high performance concrete (UHPC) is a new type of cement-based composite material, which has the advantages of ultra-high strength, ultra-high toughness, relatively stable volume, and excellent durability. The use of ultra-high performance concrete has a great effect on improving the quality of buildings, can effectively prolong the service life of buildings, and is also beneficial to improving their ability to prevent and mitigate disasters. It is suitable for the purposes of energy saving, emission reduction and sustainable development that our country currently advocates.

Contents of the invention

In order to avoid the problems of a large amount of investment in formwork frames and formwork materials in traditional formwork engineering, low turnover utilization rate, large labor input, a large amount of construction waste, and low construction efficiency; the present invention provides a new type of permanent The formwork concrete column and its manufacturing method, the method simplifies the construction procedures such as on-site formwork removal and binding steel bars, realizes the production of new permanent formwork prefabricated components without demolition and green and efficient construction, and effectively solves the problems existing in the existing formwork construction technology .

Technical solutions

The present invention proposes a method for making concrete columns using prefabricated angle steel lattice permanent formwork, including angle steel 2 built into the permanent formwork, steel patch connectors 3 between the angle steels, connection welds 4 before the angle steel and patch panels, prefabricated permanent UHPC (Ultra High Performance Concrete) used in formwork 1, plain concrete filled inside 5.

A method for manufacturing a permanent formwork concrete column using a prefabricated angle steel lattice structure, comprising the following steps:

The first step is to prepare the UHPC required in the prefabricated permanent formwork, and determine the UHPC mix ratio with the best mechanical properties through the test of cubic compressive strength, compressive modulus of elasticity, flexural strength, etc., and further optimize To reduce the cost of materials, in the present invention, the traditional quartz sand is replaced by ordinary washed river sand, the apparent density is 2.62g/cm ³ , the fineness modulus is 2.6, the sediment content is 0.2%, and the quartz powder is adjusted to 400 mesh Ground calcium carbonate powder;

The second step is to calculate the size of the rigid plate 3 in the permanent formwork of the built-in angle steel composite structure through the design bearing capacity;

The third step is to make an angle steel lattice composite structure on the bottom plate made of square steel plates, set angle steel 2 at the four corners of the column, calculate the required angle steel length according to the structural requirements, and reserve the required angle steel length for connection;

The fourth step is to weld 4 steel trims 3 between the angle steels as shown in the figure according to the size and quantity of trims calculated in step 1;

The fifth step is to reserve a protective layer thickness of 20mm for the outer mold and inner membrane of the permanent formwork; the thickness of the formwork is determined by the cross-sectional area of the built-in angle steel composite structure configured under the actual bearing capacity;

The sixth step is to mix the ultra-high performance concrete (UHPC) used in the formwork with a horizontal shaft forced mixer or a new type of counter-flow or planetary mixer, and pour it;

The seventh step is to maintain the permanent formwork of the angle steel lattice structure. In the permanent formwork of the built-in angle steel lattice structure steel structure, due to the shrinkage and creep properties of UHPC different from ordinary concrete, the maintenance must be strengthened during construction, especially the early wet curing ; For the column permanent formwork described in the present invention, it is necessary to remove the formwork in advance for maintenance;

The eighth step is to pour ordinary concrete inside the permanent formwork 5.

The present invention proposes a prefabricated connection method for the construction of permanent formwork concrete columns with prefabricated angle steel lattice structures. The main method is to use high-strength bolts to connect the angle steel in the upper and lower concrete columns with the prefabricated steel components; wherein the main structure includes: concrete column angle steel And the reserved bolt holes 7-13 of the steel component, the steel plate 16 of the side elevation of the prefabricated steel component, the stiffeners 14, 15 in the side elevation of the prefabricated steel component, and the stiffener 17 inside the prefabricated steel component.

A prefabricated connection method when using prefabricated angle steel lattice permanent formwork concrete columns for construction, including the following steps:

In the first step, the lower column poured and manufactured according to the above method is connected with the prefabricated steel structure connectors by using the reserved angle steel and its bolt holes 7-13 through high-strength bolts, and the serial numbers need to correspond one by one as shown in the figure;

In the second step, the upper column of the UHPC permanent formwork of the built-in angle steel lattice composite structure without pouring internal ordinary concrete is connected with the prefabricated steel structure connectors through high-strength bolts using the reserved angle steel and its bolt holes;

In the third step, the ordinary concrete 5 inside the upper column and the inside of the prefabricated rigid structure connector is integrally poured from the top of the upper column, and fully vibrated;

The fourth step is to use concrete to smooth the side elevation and front elevation of the connection between the rigid components in the middle of the upper and lower columns, so that the upper and lower columns and the connection are formed as a whole;

The fifth step is to maintain the internal concrete.

Beneficial effects: Compared with the prior art, the manufacturing method of the permanent formwork concrete column using prefabricated angle steel lattice structure according to the present invention has the following technical effects:

1. The method for making concrete columns using prefabricated angle steel lattice permanent formwork according to the present invention can greatly improve the construction efficiency of formwork engineering in building construction, and avoid tedious steps such as formwork support and formwork removal, making construction easier industrialization and modernization;

2. The method for making concrete columns using prefabricated angle steel lattice permanent formwork according to the present invention can effectively alleviate the problem of construction waste on the construction site. The permanent free formwork proposed by the present invention is different from the traditional formwork that requires formwork removal, which is beneficial to the present stage The green construction advocated reduces environmental pollution and reduces the waste of wood resources in traditional wood formwork construction;

3. The method for making concrete columns using prefabricated angle steel lattice permanent formwork according to the present invention can effectively simplify the construction process and improve construction efficiency in the process of subsequent concrete pouring, and has the advantages of environmental protection, easy operation, energy saving and high efficiency ;

4. The manufacturing method of the concrete column using the prefabricated angle steel lattice permanent formwork described in the present invention, because the prefabricated formwork is prefabricated in the factory, there are few uncontrollable factors on site, so the production accuracy is high, and the error is lower than that of the on-site construction. It makes the subsequent installation easier and more in line with the structural design results, which is conducive to the quality control of the building;

5. The method for making concrete columns using prefabricated angle steel lattice permanent formwork described in the present invention effectively improves the compressive strength of concrete columns due to the use of ultra-high performance concrete and angle steel lattice structures in permanent formwork, which is beneficial to construction Design and material savings;

6. The construction connection method of the prefabricated angle steel lattice type permanent formwork column described in the present invention is easy to implement at the construction site, saves labor and technical requirements; can guarantee the construction quality to a greater extent and increase the construction speed.

Preferably, when making the permanent formwork with built-in angle steel lattice, a section of angle steel should be reserved according to the designed column height and bolt holes 7-13 should be provided for subsequent connection.

Preferably, the ultra-rigid concrete (UHPC) 1 inside the permanent formwork is mixed using a horizontal shaft forced mixer or a new type of countercurrent or planetary mixer.

Preferably, when the ultra-rigid concrete (UHPC) 1 inside the permanent formwork is vibrated, a high-frequency vibrator is used to fully vibrate it.

Preferably, when the (UHPC) 1 prepared in the pouring formwork is prepared, the pouring method of planar pouring is selected in the present invention.

Preferably, in order to save cost in the ultra-rigid concrete (UHPC) 1 inside the permanent formwork, the quartz sand is replaced with ordinary washed river sand.

Preferably, high-strength bolts are used for connecting the upper and lower columns.

Description of drawings

The drawings constituting a part of this application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention.

Fig. 1 is a top sectional view of a concrete column using a prefabricated angle steel lattice permanent formwork according to the present invention.

Fig. 2 is a front sectional view of a permanent form in a concrete column using a prefabricated angle steel lattice permanent form according to the present invention.

Fig. 3 is an overall structural diagram of the method for connecting concrete columns using a prefabricated angle steel lattice permanent formwork according to the present invention.

Fig. 4 is a side elevational view of the prefabricated steel connector in the method for connecting concrete columns using a prefabricated angle steel lattice permanent formwork according to the present invention.

Fig. 5 is a front elevation view of the prefabricated steel connector in the method for connecting concrete columns using a prefabricated angle steel lattice permanent formwork according to the present invention.

Explanation of reference signs: 1-UHPC (Ultra High Performance Concrete); 2-The built-in angle steel in the permanent formwork; 3-The steel panel with lattice structure in the permanent formwork; 4-The panel and the angle steel are connected by welding; 5- Ordinary concrete inside the permanent formwork; 6-Angle steel reserved for subsequent column-to-column connections; 7-13-Reserved bolt holes for concrete column angle steel and steel components; 16-Side steel plates for prefabricated steel components; 14, 15-stiffeners in the facade of prefabricated steel components; 17-stiffeners inside prefabricated steel components.

Detailed ways

The specific embodiment of the present invention is described in further detail below in conjunction with accompanying drawing:

1. Prepare the UHPC (Ultra High Performance Concrete) required in the prefabricated permanent formwork;

Determine the UHPC mix ratio with the best mechanical properties through the tests of cubic compressive strength, compressive modulus of elasticity, flexural strength, etc. to determine the mechanical properties, wherein in order to further optimize and reduce material costs, the traditional quartz sand is replaced by ordinary in the present invention. Washed river sand has an apparent density of 2.63g/cm ³ , a fineness modulus of 2.5, and a sediment content of 0.2%; and the quartz powder is adjusted to 400 mesh heavy calcium carbonate powder;

After the preparation is completed, take the UHPC designed according to the mix ratio in Table 1 and make a 100mm cube test block, and carry out the cube compressive strength test through the hydraulic servo testing machine, and the average compressive strength of UHPC is 130MPa;

Excessive fiber content will affect the flexural strength of UHPC, and too much steel fiber will reduce the fluidity of UHPC, greatly increase the difficulty of pouring and mixing, and affect the quality of finished components, so the proportion of fiber rigidity should be appropriately reduced; at the same time, UHPC The elastic modulus has a great relationship with the water-cement ratio. It is measured through experiments that under the same fiber content conditions, the specimen with a lower water-cement ratio has a higher modulus of elasticity.

Table 1 Mixing ratio of UHPC

2. Make UHPC permanent formwork with built-in angle steel lattice structure;

Step 1: Calculate the size of the rigid plate 3 in the permanent formwork of the built-in angle steel composite structure through the design bearing capacity;

In the present invention, since the steel slab is equivalent to the stirrup in the ordinary column member, the minimum stirrup ratio of the component is calculated according to the characteristic value of the minimum stirrup ratio of the design axial compression ratio under different seismic grades specified in the "Code for Design of Concrete Structures" ratio, so as to determine the size and quantity of steel panels in the component; in the present invention, the design axial compression ratio and the test axial compression ratio are obtained through conversion, and the conversion relationship between the two is: n _d = 2.14n ₀ , by consulting relevant literature and materials. where n _d is the design axial compression ratio; n ₀ is the test axial compression ratio; the test axial compression ratio adopts the axial compression of ordinary reinforced concrete columns stipulated in "Code for Design of Concrete Structures" (GB50011) and "Code for Seismic Design of Buildings" (GB50011) The expression of the ratio is calculated;

By observing the model column method to calculate the load-displacement (p-Δ) relationship of the specimen, it is obtained that the test axial compression ratio n ₀ , design value of axial compressive strength f _c , steel content ratio P _s , yield strength f _y and shear When the span ratio λ is constant, the p-Δ curves under different hoop ratios can be obtained. The increase of the hoop ratio has little influence on the bearing capacity of the construction, but has a great effect on the improvement of the ductility of the construction; therefore, the present invention The UHPC permanent formwork with built-in angle steel lattice structure can appropriately increase the hoop ratio to improve the ductility of the structure;

Step 2: Make an angle steel lattice combination structure on the bottom plate made of square steel plates, set angle steel 2 at the four corners of the column, calculate the required angle steel length according to the structural requirements, and reserve the required angle steel length for connection;

Step 3: Weld 4 steel trims 3 between the angle steels as shown in the figure according to the size and quantity of trims calculated in Step 1;

Step 4: To support the outer mold and inner membrane of the permanent formwork, reserve a protective layer thickness of 20mm; the thickness of the formwork is determined by the cross-sectional area of the built-in angle steel composite structure configured under the actual bearing capacity;

Step 5: Mix the ultra-high performance concrete (UHPC) used in the formwork with a horizontal shaft forced mixer or a new type of countercurrent or planetary mixer;

When pouring UHPC prepared in the formwork, there are two types of plane pouring and slit pouring. Since UHPC itself has good fluidity and has a flat self-flowing effect, the pouring method of plane pouring is selected in the present invention to make the components more smooth. , dense appearance;

Step 6: Use a high-frequency vibrator to fully vibrate the UHPC in the permanent formwork of the angle steel lattice;

Step 7: Maintain the permanent formwork of the angle steel lattice. In the permanent formwork of the built-in angle steel lattice type steel structure, since UHPC is different from the shrinkage and creep properties of ordinary concrete, maintenance must be strengthened during construction, especially early wet maintenance; for the column permanent formwork described in the present invention , it needs to be demolished and cured in advance; high temperature curing is beneficial to increase the compactness of components caused by silica fume reaction in UHPC, and since the concrete is ultra-high performance concrete with additives, the curing time is not less than 14 days. During this period, the internal temperature of the concrete should not be higher than 750°C, and measures should be taken to make the temperature difference between the inside and outside of the specimen not greater than 250°C; it is advisable to use spray instead of watering in the early stage of maintenance to avoid side effects caused by excessive temperature differences inside and outside the concrete. Unfavorable effects such as concrete cracking; based on the above analysis, the UHPC permanent formwork member with built-in angle steel lattice combined structure according to the present invention adopts a curing box for 90°C hot water curing, and the specific curing measures are: (1). Indoor static 1d demoulding; (2) hot water curing with a curing box for 2d; (3) standard indoor curing at room temperature for 28d.

During specific implementation, since the bearing capacity of the permanent formwork concrete column of the prefabricated angle steel lattice structure in the present invention also has a great relationship with the strength of the steel and the strength of the internal concrete; so it is necessary to select a suitable steel model and concrete strength according to the design bearing capacity of the overall structure grade;

In practice, in order to prevent premature shear failure of components, the shear-span ratio of the structure needs to be adjusted according to the actual design size; λ=M/(Vh ₀ ), where M is the bending moment at the end of the frame column, and V is the frame column The end shear force, h ₀ is the effective height of the column section in the direction parallel to the bending moment M. It can be seen from the general law that the reasonable configuration of the stirrup (and the steel panel in the present invention) can effectively adjust the overall shear-span ratio of the member.

3. Pouring ordinary concrete inside the permanent formwork;

Due to the small cross-sectional area of the external permanent formwork, in order to ensure the integrity of the test block and the sufficient bearing capacity of the column specimen, the stone is replaced by quartz sand in the internal post-cast concrete; the concrete strength grade is determined by the actual design bearing capacity demand selection;

When the concrete is poured into the mold, it is not allowed to dump the impact formwork in a concentrated manner. When the height is greater than 2M, stringing tubes and slide pipes should be used for feeding. The free falling height from the discharge nozzle to the pouring layer shall not exceed 1.5M, and the concrete must be completed within five hours. Pouring completed;

During the pouring process, the duration of vibration should be such that the surface of the concrete produces laitance, no air bubbles, and no sinking; the insertion points of the vibrator are evenly arranged in a quincunx shape, and the order of the determinant is used to move, and the distance of the moving position should not be greater than 40CM. Guaranteed no vibration leakage, no vibration;

After the second and third times of plastering on the concrete surface, it should be covered and cured in time. After the concrete has finally set, it should be fully wetted with water, and then sealed and covered with a plastic film, and the surface of the plastic film should be checked frequently, but the surface of the film is dry. When the beads are removed, water should be sprinkled again. The curing time shall not be less than 7 days.

Four, the present invention also comprises a kind of connection method of prefabricated angle steel lattice type permanent formwork concrete column in construction;

Step 1: Use the reserved angle steel and its bolt holes 7 to 13 to connect the lower column poured and manufactured according to the aforementioned method to the prefabricated steel structure connectors through high-strength bolts, and the serial numbers need to correspond one by one as shown in the figure;

Step 2: Connect the upper column of the UHPC permanent formwork of the built-in angle steel lattice composite structure without pouring internal ordinary concrete to the prefabricated steel structure connectors through high-strength bolts using the reserved angle steel and its bolt holes;

Step 3: integrally pour the ordinary concrete 5 inside the upper column and inside the prefabricated rigid structure connector from the top of the upper column, and fully vibrate;

Step 4: Use concrete to level the joints of the rigid components in the middle of the upper and lower columns on the side facade and front facade, so that the upper and lower columns and the joints form a whole;

Step 5: Curing the internal concrete.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail; it should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A method for preparing a permanent formwork concrete column using a prefabricated angle steel lattice, comprising the following steps: Step 1. Prepare the ultra-high-performance concrete required in the prefabricated permanent formwork, and determine the mix ratio of the ultra-high-performance concrete with the best mechanical properties through the test of cubic compressive strength and compressive modulus of elasticity. The fine sand is washed by water Sand with an apparent density of 2.62g/cm ³ , a fineness modulus of 2.6, and a sediment content of 0.2%. The calcium powder is 400 mesh heavy calcium carbonate powder; The mix ratio of ultra-high performance concrete: Cement: 1 Silica fume: 0.24 Calcium powder: 0.31 Fine sand: 1.0 Water: 0.22 Fiber Steel: 0.016 Water reducer: 0.037 After the preparation is completed, the cubic test block is designed according to the mix ratio, and the cubic compressive strength test is carried out to obtain ultra-high performance concrete with an average compressive strength of 130MPa; Step 2. Calculate the size and quantity of the steel panels (3) in the permanent formwork through the design bearing capacity; Step 3. Make a built-in angle steel lattice structure on the bottom plate made of square steel plates, set angle steel (2) at the four corners of the column, calculate the length of the required angle steel (2) according to the structural requirements, and reserve the required space for connection Angle steel length; Step 4. Weld steel trims between angle steels according to the size and quantity of steel trims calculated in step 2 (3); Step 5. For the outer mold and inner mold of the permanent formwork, a protective layer thickness of 20mm is reserved, and the thickness of the formwork is determined by the cross-sectional area of the built-in angle steel lattice structure that is configured under the actual bearing capacity conditions; Step 6. Use a horizontal shaft forced mixer or a countercurrent or planetary mixer to mix the ultra-high performance concrete (1) used in the formwork and pour it; Step 7. Maintain the permanent formwork. After the pouring is completed, let it sit indoors for 1 day to remove the formwork, use a curing box for hot water curing for 2 days, and standard indoor curing at room temperature for 28 days; Step 8: Pour ordinary concrete inside the permanent formwork. 2. According to claim 1, a method for making concrete columns using prefabricated angle steel lattice permanent formwork, characterized in that: said permanent formwork pouring ultra-high performance concrete (1) adopts a plane pouring method, fully vibrating and curing, and the internal The strength of ordinary concrete should be calculated according to the design bearing capacity, adding reinforcement cages to increase its bearing capacity. 3. The manufacturing method of the prefabricated angle steel lattice permanent formwork concrete column according to claim 1, characterized in that: the inner wall of the prefabricated permanent formwork should be cleaned and chiseled before pouring the internal ordinary concrete, so as to facilitate full connection. 4. A connection method for a prefabricated angle steel lattice permanent formwork concrete column, characterized in that: Step 1: Connect the lower column manufactured according to the method as claimed in claim 1 with the prefabricated steel structure connecting piece by using the reserved angle steel and its bolt holes through high-strength bolts; Step 2: Connect the upper column of the UHPC permanent formwork of the built-in angle steel lattice composite structure without pouring internal ordinary concrete to the prefabricated steel structure connectors through high-strength bolts using the reserved angle steel and its bolt holes; Step 3: integrally pour the ordinary concrete (11) inside the upper column and inside the prefabricated steel structure connectors from the top of the upper column, and fully vibrate; Step 4: Use concrete to smooth the side elevation and front elevation of the connection between the steel components in the middle of the upper and lower columns, so that the upper and lower columns and the connection are formed as a whole; Step 5: Carry out maintenance on the internal ordinary concrete.

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