Prestressed Pile to Bent Cap Connections: Seismic Performance of a Full-Scale Three-Pile Specimen

The South Carolina DOT employs a detail in which piles are plainly embedded into bent caps without the use of any special detailing to the pile. The behavior of these connections is of special concern in areas where seismic activity poses a threat to infrastructure. This paper discusses the experimental results of a full-scale three-pile bent specimen subjected to a modified earthquake displacement history. This study is significant in the type of loading applied, the scale of the specimen, the inclusion of multiple piles, and the evaluation of differing bent cap reinforcement designs. The specimen was the culmination of an experimental research effort that included eight full-scale single-pile specimens. Results of the full-scale experiment and a numerical model are used for evaluation of the connection as well as comparison between differing reinforcement designs at exterior ends of the bent cap. These results include concrete cracking and spalling, strand slippage, ductility, and the amount of confinement at each connection.