The Experts below are selected from a list of 302601 Experts worldwide ranked by ideXlab platform
Dimitrios Lignos - One of the best experts on this subject based on the ideXlab platform.
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full scale Testing of deep wide flange steel columns under multiaxis cyclic loading loading sequence boundary effects and lateral stability bracing force demands
Journal of Structural Engineering-asce, 2018Co-Authors: Ahmed Elkady, Dimitrios LignosAbstract:AbstractThis paper discusses the findings from 10 Full-Scale steel column tests subjected to multiaxis cyclic loading. The columns use deep wide-flange cross sections typically seen in steel moment...
Sharmila Pant - One of the best experts on this subject based on the ideXlab platform.
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developing guidelines for epoxy grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale Testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with epoxy grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger epoxy grout pourbacks, possibly as a result of the exothermic nature of the epoxy grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in epoxy grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An epoxy grout pourback material was used to construct Full-Scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The Full-Scale specimens wer...
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develop epoxy grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in epoxy grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected epoxy grout pourback material and finite element analysis on the Full-Scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of epoxy grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and Full-Scale Testing potential factors affecting epoxy grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the Full-Scale Testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the Full-Scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the epoxy grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and Full-Scale specimens were full-depth cracks that penetrated through the epoxy grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the epoxy grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
Irtishad Ahmad - One of the best experts on this subject based on the ideXlab platform.
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developing guidelines for epoxy grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale Testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with epoxy grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger epoxy grout pourbacks, possibly as a result of the exothermic nature of the epoxy grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in epoxy grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An epoxy grout pourback material was used to construct Full-Scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The Full-Scale specimens wer...
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develop epoxy grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in epoxy grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected epoxy grout pourback material and finite element analysis on the Full-Scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of epoxy grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and Full-Scale Testing potential factors affecting epoxy grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the Full-Scale Testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the Full-Scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the epoxy grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and Full-Scale specimens were full-depth cracks that penetrated through the epoxy grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the epoxy grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
Ahmed Elkady - One of the best experts on this subject based on the ideXlab platform.
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full scale Testing of deep wide flange steel columns under multiaxis cyclic loading loading sequence boundary effects and lateral stability bracing force demands
Journal of Structural Engineering-asce, 2018Co-Authors: Ahmed Elkady, Dimitrios LignosAbstract:AbstractThis paper discusses the findings from 10 Full-Scale steel column tests subjected to multiaxis cyclic loading. The columns use deep wide-flange cross sections typically seen in steel moment...
Andrea Pattarini - One of the best experts on this subject based on the ideXlab platform.
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full scale Testing and numerical analysis of a precast fibre reinforced self compacting concrete slab pre stressed with basalt fibre reinforced polymer bars
Composites Part B-engineering, 2017Co-Authors: Bruno Dal Lago, Su Taylor, Peter Deegan, Philip Crosset, Liberato Ferrara, Mohammed Sonebi, Andrea PattariniAbstract:Abstract Steel-free pre-stressed reinforced concrete may be used in aggressive environments to increase the durability of structural elements and to limit the carbon footprint by replacing steel with high-strength fibre composites. The design of a 10-m long steel-free precast fibre-reinforced concrete slab, pre-stressed with basalt-fibre reinforced polymer (BFRP) bars and shear-reinforced with glass-fibre reinforced polymer bars, is presented in this paper. Non-linear viscoelastic and elastic-plastic models have been employed for the prediction of the service and ultimate limit state flexural behaviour, respectively. Preliminary tests on the employed materials and a 3-point load test on the slab element are presented, together with indications on its manufacturing process. The proposed numerical analysis is validated against the experimental results.
