Shaking table tests of subway station-bridge complex structure to evaluate nonlinear seismic response under strong earthquakes

To investigate the nonlinear seismic performance of subway station-bridge complex structures during strong earthquakes, shake table tests were conducted on specimens consisting of a two-story three span subway station and a three-span variable cross-section steel box girder bridge. Two scaled specimens were designed and tested with a geometric similarity ratio of 1/40, representing integral and separated configuration between station and bridge. The results show that damage mainly occurs on the bridge piers in both the integral and separated system, and the underground subway stations generally remain elastic throughout the whole test. Due to the existence of gravel cushion, the separated system undergoes slighter damage, since it behaves more like a rigid body and its sliding on the cushion dissipates part of the seismic energy. Overall, the separated system is shown with superior seismic performance over its integral counterpart, and more adaptable to the complex requirements in strong earthquake environments. This study is believed providing substantial reference and support for the seismic design of the novel subway station-bridge complex systems.