Dr.
Paul H. Ziehl, Dr. Juan M. Caicedo, Dr. Dimitris Rizos, Dr. Timothy Mays, Aaron
Larosche, Mohamed ElBatanouny, and Brad
Mustain
Federal Highway Administration and South Carolina Department of Transportation
Currently, the South Carolina Department of Transportation (SCDOT) specifies cast-in-place bent caps for bridge construction. However, the SCDOT recognizes the potential merit of precast bent caps and is interested in using these caps as part of the Road S-31 Bridge Replacement Project in Horry County South Carolina. The use of a precast bent cap as opposed to a cast-in-place cap could aid in the construction time and cost of this project as well as others in the future. As a result, the University of South Carolina has concluded an investigation related to the viability and performance of a precast bent cap system.
South Carolina is considered to be a high seismicity area. When subjected to large seismic events the ductility of bridge systems is of extreme importance. Although ongoing research of cast-in-place caps has shown elastic response and adequate capacity protection of these elements, similar performance of precast caps is uncertain in the absence of additional research. Pile installation tolerances require large openings in the precast caps and result in precast cap dimensions that are larger than those used for typical cast-in-place projects. Reinforcing details can be similar to those used in cast-in-place projects but bar placement near the pile is also difficult due to construction tolerances. Finally, closure pours as required to tie the precast caps to the pile heads are typically made with non-shrink or low shrink grout and may result in less confinement of pile heads as compared to cast-in-place projects. This report presents the results of a research project related to a prestressed concrete pile to precast bent cap connection detail. The detail achieved the necessary ductility capacity via pile hinging while protecting the cap under reverse cyclic loading.
Since beginning work on this project, the University has consulted with industry partners aiding in the process to design a precast cap suitable for withstanding the seismic events expected in South Carolina. In conjunction with input from local industry members, University of South Carolina has developed computer models to simulate the design of the cap subjected to seismic forces. The precast caps themselves were designed by a regional consulting firm. Upon completion of the assembly and instrumentation of the precast caps and piles, University of South Carolina completed the testing of two full-scale single pile bent cap specimens. Both a single pile interior and single pile exterior specimen were fabricated and tested at the University of South Carolina’s structures laboratory. The precast caps and prestressed piles were both fabricated by Florence Concrete Products of Sumter, South Carolina. The design of these experiments was intentionally similar to that of the ongoing cast-in-place bent cap research project’s preliminary results of which are reported by Larosche et al., 2010.
Federal Highway Administration and South Carolina Department of Transportation
Currently, the South Carolina Department of Transportation (SCDOT) specifies cast-in-place bent caps for bridge construction. However, the SCDOT recognizes the potential merit of precast bent caps and is interested in using these caps as part of the Road S-31 Bridge Replacement Project in Horry County South Carolina. The use of a precast bent cap as opposed to a cast-in-place cap could aid in the construction time and cost of this project as well as others in the future. As a result, the University of South Carolina has concluded an investigation related to the viability and performance of a precast bent cap system.
South Carolina is considered to be a high seismicity area. When subjected to large seismic events the ductility of bridge systems is of extreme importance. Although ongoing research of cast-in-place caps has shown elastic response and adequate capacity protection of these elements, similar performance of precast caps is uncertain in the absence of additional research. Pile installation tolerances require large openings in the precast caps and result in precast cap dimensions that are larger than those used for typical cast-in-place projects. Reinforcing details can be similar to those used in cast-in-place projects but bar placement near the pile is also difficult due to construction tolerances. Finally, closure pours as required to tie the precast caps to the pile heads are typically made with non-shrink or low shrink grout and may result in less confinement of pile heads as compared to cast-in-place projects. This report presents the results of a research project related to a prestressed concrete pile to precast bent cap connection detail. The detail achieved the necessary ductility capacity via pile hinging while protecting the cap under reverse cyclic loading.
Since beginning work on this project, the University has consulted with industry partners aiding in the process to design a precast cap suitable for withstanding the seismic events expected in South Carolina. In conjunction with input from local industry members, University of South Carolina has developed computer models to simulate the design of the cap subjected to seismic forces. The precast caps themselves were designed by a regional consulting firm. Upon completion of the assembly and instrumentation of the precast caps and piles, University of South Carolina completed the testing of two full-scale single pile bent cap specimens. Both a single pile interior and single pile exterior specimen were fabricated and tested at the University of South Carolina’s structures laboratory. The precast caps and prestressed piles were both fabricated by Florence Concrete Products of Sumter, South Carolina. The design of these experiments was intentionally similar to that of the ongoing cast-in-place bent cap research project’s preliminary results of which are reported by Larosche et al., 2010.
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