Plain Pile Embedment for Exterior Bent Cap Connections in Seismic Regions

Abstract

Four full-scale exterior bent cap connections utilizing plain pile embedment were evaluated for suitability in seismic regions. A self-reacting test setup was used to investigate the special case of reverse axial tension and compressive loading expected to occur in the exterior portions of bridge bents. The current state of practice design detail was first evaluated and performed unsatisfactorily. Three additional specimens were then specially designed and evaluated. Specimen variables include embedment depth of the prestessed pile, bent cap reinforcement design, and bent cap dimensions. Specimens were evaluated in terms of moment capacity, plastic hinge length, ductility, and damage to the bent cap. Design alternatives include an idealized hinge connection and two moment transfer connections. The results indicate that the use of plain pile embedment is feasible for regions similar in level of seismicity to South Carolina, provided that the embedment depth is sufficient.