Seismic Design and Experimental Verification of Concrete Multiple Column Bridge Bents

Following widespread bridge damage in recent California earthquakes, a significant amount of research has been carried out to improve seismic performance of bridge structures. Compiling recent advances, two large-scale concrete multiple-column bridge bents were designed and subjected to simulated earthquake loading at the University of California, San Diego (UCSD). In addition to serving as proof-test specimens, these bridge bents facilitated investigation of improved cap beam-to-column joint reinforcement details to minimize construction difficulties. The design of the joints in the first test unit was simplified by using prestressing in the bent cap and examining the force transfer across the joint, which also enabled introduction of precast construction for concrete multiple column bents. In the second test unit, joint reinforcement was minimized by utilizing efficient joint force transfer models and special reinforcement products. Design details, seismic performance, and some test results of the multiple column bents are presented in this paper.