Structural Materials Technology III: An NDT Conference, 1998
ABSTRACT On-line, continuous monitoring technologies of a rigorous and objective nature are sough... more ABSTRACT On-line, continuous monitoring technologies of a rigorous and objective nature are sought to quantitatively identify and evaluate the condition or health of highway structures over their useful lifetime. A global bridge evaluation methodology is under development based upon the structural identification concept, employing modal testing, truckload testing, and instrumented monitoring as its principal experimental tools. Test results are transformed to either modal flexibility or the unit influence line, which have been demonstrated to be conceptual, quantitative, comprehensive, and damage-sensitive signatures. Four test sites were tested, monitored, and studied in order to classify their similar bride-type-specific behavior mechanisms and to validate the performance of the implemented methodology. Practical, type-specific procedures for instrumented monitoring and nondestructive evaluation can then be developed for the whole group or type of highway bridges.
... Raymond Barrish, Necati Catbas, Kirk Grimmelsman, A. Emin Aktan Drexel Intelligent Infrastruc... more ... Raymond Barrish, Necati Catbas, Kirk Grimmelsman, A. Emin Aktan Drexel Intelligent Infrastructure Institute (DIII), 3201 ... Aktan, AE, et al., “Condition Assessment for Bridge Management.” Journal of Infrastructure ... Lenett, M., et al., “Issues In Multi-Reference Impact Testing of Steel ...
... AHMET TURER AND A. EMIN AKTAN Page 2. 88 Paper No. 99-0385 TRANSPORTATION RESEARCH RECORD 168... more ... AHMET TURER AND A. EMIN AKTAN Page 2. 88 Paper No. 99-0385 TRANSPORTATION RESEARCH RECORD 1688 9.1-m-(30-ft) wide, side-by-side, separate bridges with a total of eight girders and has a skew angle of 42 degrees, the largest among the three bridges. ...
ABSTRACT Hasankeyf historic settlement area is one the most important sites in southeastern Anato... more ABSTRACT Hasankeyf historic settlement area is one the most important sites in southeastern Anatolia which dates back to the 15th century. Zeynelbey Tomb is a distinct cylindrical structure has a height of 9.6 m and with double domes extending to an overall height of 16.5m; however, the outer dome suffers from multiple and large vertical tension cracks threatening the overall structural stability and safety of the structure. A preliminary visual inspection and structural evaluation using analytical modeling was carried out. The tension zones developing at the outer dome was determined using analytical simulations and causes of vertical tension cracks were elaborated. A general remedy of strengthening was developed to surround the dome using vertical ribs and horizontal post tensioning strands that are placed in three vertical layers. The deterministic analytical simulations using the horizontal post-tensioning have allowed finding the necessary amount of tension force in each horizontal strand to diminish the tensile stresses inside the dome and put the structure in a stable compression state. This paper describes the steps carried out for the assessment, evaluation, and retrofit studies, which might set an example to similar historic structures with comparable structural problems in the dome.
Page 1. Testing and Seismic Capacity Evaluation of a Typical Traditional Ottoman Timber Frame AKT... more Page 1. Testing and Seismic Capacity Evaluation of a Typical Traditional Ottoman Timber Frame AKTAS Erdem, DIDEM Yasemin1, a, TURER Ahmet1,b, ERDIL Baris1,c, AKYUZ Ugurhan1,d and SAHIN Guchan Neriman2,e ...
Slope stability analysis of municipal solid waste has always been problematic because of the hete... more Slope stability analysis of municipal solid waste has always been problematic because of the heterogeneous nature of the waste materials. The requirement for large testing equipment in order to obtain representative samples has identified the need for simplified approaches to obtain the unit weight and shear strength parameters of the waste. In the present study, two of the most recently published approaches for determining the unit weight and shear strength parameters of the waste have been incorporated into a slope stability analysis using the Bishop method to prepare slope stability charts. The slope stability charts were prepared for uncontrolled waste dumps having no liner and leachate collection systems with pore pressure ratios of 0, 0.1, 0.2, 0.3, 0.4 and 0.5, considering the most critical slip surface passing through the toe of the slope. As the proposed slope stability charts were prepared by considering the change in unit weight as a function of height, they reflect field conditions better than accepting a constant unit weight approach in the stability analysis. They also streamline the selection of slope or height as a function of the desired factor of safety.
... Structural Analysis of Historical Constructions Page 3. Yasemin D. Aktaş, Ahmet Türer, and Em... more ... Structural Analysis of Historical Constructions Page 3. Yasemin D. Aktaş, Ahmet Türer, and Emine C. Saltık transmitter and receiver probes, was used. ... Page 5. Yasemin D. Aktaş, Ahmet Türer, and Emine C. Saltık By using the Eq. (6), Ee was approximately found as 1005 MPa. ...
Alternative methods to one-dimensional (1D) model based load rating for steel stringer bridges ar... more Alternative methods to one-dimensional (1D) model based load rating for steel stringer bridges are further explored. Geometric model generation and load definition for 2D-Grid and 3D finite element (FE) models are streamlined by developing computer programs, and generation/definition time is drastically reduced. Two-dimensional grid model calibration is automated. Six typical steel stringer highway bridges (in operation) are used for modeling, testing, and calibration. The generated models are used to simulate x-brace and unintended composite action losses, which are believed to happen prior to reaching the rating load of a bridge. The rating factors for each model are obtained using different model types (i.e., 2D-Grid and 3D-FEM), modeling levels (i.e., nominal and calibrated), rating methods (i.e., ASD and LFD), rating levels (i.e., inventory and operating), and rating conditions (i.e., "as-is", "x-braces loss", and "composite action loss"). The rati...
Non-engineered masonry houses constitute a major portion of the building stock in developing coun... more Non-engineered masonry houses constitute a major portion of the building stock in developing countries. Although masonry houses have major walls resisting lateral earthquake forces, the unreinforced nature and commonly weak inter-bonding and material properties of these walls make them vulnerable to earthquakes. A simple yet effective and economical strengthening technique was investigated for the seismic strengthening of masonry houses which have reinforced concrete decks. Placement of vertical post-tensioning bars between the floor and ceiling provided increase in strength multiple times the original capacity and improved behavior of masonry walls. A special spring box system was developed to maintain the major portion of the post-tensioning force in vertical tendons although almost all of the post-tensioning force is lost with the conventional systems as the walls pass their cracking capacity and move into nonlinear range. A heat stretching technique was developed to further redu...
Structural Materials Technology III: An NDT Conference, 1998
ABSTRACT On-line, continuous monitoring technologies of a rigorous and objective nature are sough... more ABSTRACT On-line, continuous monitoring technologies of a rigorous and objective nature are sought to quantitatively identify and evaluate the condition or health of highway structures over their useful lifetime. A global bridge evaluation methodology is under development based upon the structural identification concept, employing modal testing, truckload testing, and instrumented monitoring as its principal experimental tools. Test results are transformed to either modal flexibility or the unit influence line, which have been demonstrated to be conceptual, quantitative, comprehensive, and damage-sensitive signatures. Four test sites were tested, monitored, and studied in order to classify their similar bride-type-specific behavior mechanisms and to validate the performance of the implemented methodology. Practical, type-specific procedures for instrumented monitoring and nondestructive evaluation can then be developed for the whole group or type of highway bridges.
... Raymond Barrish, Necati Catbas, Kirk Grimmelsman, A. Emin Aktan Drexel Intelligent Infrastruc... more ... Raymond Barrish, Necati Catbas, Kirk Grimmelsman, A. Emin Aktan Drexel Intelligent Infrastructure Institute (DIII), 3201 ... Aktan, AE, et al., “Condition Assessment for Bridge Management.” Journal of Infrastructure ... Lenett, M., et al., “Issues In Multi-Reference Impact Testing of Steel ...
... AHMET TURER AND A. EMIN AKTAN Page 2. 88 Paper No. 99-0385 TRANSPORTATION RESEARCH RECORD 168... more ... AHMET TURER AND A. EMIN AKTAN Page 2. 88 Paper No. 99-0385 TRANSPORTATION RESEARCH RECORD 1688 9.1-m-(30-ft) wide, side-by-side, separate bridges with a total of eight girders and has a skew angle of 42 degrees, the largest among the three bridges. ...
ABSTRACT Hasankeyf historic settlement area is one the most important sites in southeastern Anato... more ABSTRACT Hasankeyf historic settlement area is one the most important sites in southeastern Anatolia which dates back to the 15th century. Zeynelbey Tomb is a distinct cylindrical structure has a height of 9.6 m and with double domes extending to an overall height of 16.5m; however, the outer dome suffers from multiple and large vertical tension cracks threatening the overall structural stability and safety of the structure. A preliminary visual inspection and structural evaluation using analytical modeling was carried out. The tension zones developing at the outer dome was determined using analytical simulations and causes of vertical tension cracks were elaborated. A general remedy of strengthening was developed to surround the dome using vertical ribs and horizontal post tensioning strands that are placed in three vertical layers. The deterministic analytical simulations using the horizontal post-tensioning have allowed finding the necessary amount of tension force in each horizontal strand to diminish the tensile stresses inside the dome and put the structure in a stable compression state. This paper describes the steps carried out for the assessment, evaluation, and retrofit studies, which might set an example to similar historic structures with comparable structural problems in the dome.
Page 1. Testing and Seismic Capacity Evaluation of a Typical Traditional Ottoman Timber Frame AKT... more Page 1. Testing and Seismic Capacity Evaluation of a Typical Traditional Ottoman Timber Frame AKTAS Erdem, DIDEM Yasemin1, a, TURER Ahmet1,b, ERDIL Baris1,c, AKYUZ Ugurhan1,d and SAHIN Guchan Neriman2,e ...
Slope stability analysis of municipal solid waste has always been problematic because of the hete... more Slope stability analysis of municipal solid waste has always been problematic because of the heterogeneous nature of the waste materials. The requirement for large testing equipment in order to obtain representative samples has identified the need for simplified approaches to obtain the unit weight and shear strength parameters of the waste. In the present study, two of the most recently published approaches for determining the unit weight and shear strength parameters of the waste have been incorporated into a slope stability analysis using the Bishop method to prepare slope stability charts. The slope stability charts were prepared for uncontrolled waste dumps having no liner and leachate collection systems with pore pressure ratios of 0, 0.1, 0.2, 0.3, 0.4 and 0.5, considering the most critical slip surface passing through the toe of the slope. As the proposed slope stability charts were prepared by considering the change in unit weight as a function of height, they reflect field conditions better than accepting a constant unit weight approach in the stability analysis. They also streamline the selection of slope or height as a function of the desired factor of safety.
... Structural Analysis of Historical Constructions Page 3. Yasemin D. Aktaş, Ahmet Türer, and Em... more ... Structural Analysis of Historical Constructions Page 3. Yasemin D. Aktaş, Ahmet Türer, and Emine C. Saltık transmitter and receiver probes, was used. ... Page 5. Yasemin D. Aktaş, Ahmet Türer, and Emine C. Saltık By using the Eq. (6), Ee was approximately found as 1005 MPa. ...
Alternative methods to one-dimensional (1D) model based load rating for steel stringer bridges ar... more Alternative methods to one-dimensional (1D) model based load rating for steel stringer bridges are further explored. Geometric model generation and load definition for 2D-Grid and 3D finite element (FE) models are streamlined by developing computer programs, and generation/definition time is drastically reduced. Two-dimensional grid model calibration is automated. Six typical steel stringer highway bridges (in operation) are used for modeling, testing, and calibration. The generated models are used to simulate x-brace and unintended composite action losses, which are believed to happen prior to reaching the rating load of a bridge. The rating factors for each model are obtained using different model types (i.e., 2D-Grid and 3D-FEM), modeling levels (i.e., nominal and calibrated), rating methods (i.e., ASD and LFD), rating levels (i.e., inventory and operating), and rating conditions (i.e., "as-is", "x-braces loss", and "composite action loss"). The rati...
Non-engineered masonry houses constitute a major portion of the building stock in developing coun... more Non-engineered masonry houses constitute a major portion of the building stock in developing countries. Although masonry houses have major walls resisting lateral earthquake forces, the unreinforced nature and commonly weak inter-bonding and material properties of these walls make them vulnerable to earthquakes. A simple yet effective and economical strengthening technique was investigated for the seismic strengthening of masonry houses which have reinforced concrete decks. Placement of vertical post-tensioning bars between the floor and ceiling provided increase in strength multiple times the original capacity and improved behavior of masonry walls. A special spring box system was developed to maintain the major portion of the post-tensioning force in vertical tendons although almost all of the post-tensioning force is lost with the conventional systems as the walls pass their cracking capacity and move into nonlinear range. A heat stretching technique was developed to further redu...
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