In-situ seismic performance test of a scoured bridge

This paper presented a series of in-situ seismic performance tests of a bridge before its demolition due to accumulated souring-induced problem. The experiment programs included three cyclical loading tests and one pseudo-dynamic test. Built in 1995, the tested three single piers was 1.8 in diameter with longitudinal ratio of 0.95% and lateral reinforce ratio of 0.294%. The aspect ratio ranges from 5.3 to 5.7. P3 column represents a benchmark specimen with exposed length of 1.2 m, while P4 was exposed up to 4 m. P2 was subjected to code-compatible ground acceleration and then followed by a one-cycle pushover test. Based on the test results, the bridge behaved mostly elastic under 0.32 g excitation. The ultimate lateral strength obtained could satisfy design target of plastic hinge moment, and the maximum drift ratio reached 5%. However, insufficient design of lateral reinforcement without seismic hook resulted in buckling of longitudinal reinforcements and loose of lateral reinforcements. Besides, it was due to gravel material and retrofitted caisson which provided large lateral resistance, even exposed 1/3 of the caisson length, the seismic performance among three piers had minor difference, and had been compared by the proposed analytical model in OpenSees with good accuracy. The experience learnt was hoped to beneficial the planning of in-situ test of a piled bridge with scouring issue, and to verify the seismic performance of bridges with similar conditions.