Collapse Failure of Prestressed Concrete Continuous Rigid-Frame Bridge under Strong Earthquake Excitation: Testing and Simulation

Abstract

In recent years, increasing attention has been paid to the collapse failures of long-span continuous rigid-frame bridges under strong earthquake excitations. This paper presents the results of a study in which a 1:15 scaled two-span prestressed concrete continuous rigid-frame bridge model with box-type piers was tested using the shake-table array test system to investigate the seismic response characteristics. Two nonlinear finite-element (FE) models were constructed. The first was a single-girder model that was used to simulate the seismic response under weak seismic waves. The second was an explicit dynamic FE model that was used to simulate the collapse and failure mechanisms of the scaled bridge under strong earthquakes. Testing revealed that the response of the central pier of the prestressed concrete continuous rigid-frame bridge was the largest under seismic excitation, and the damage first appeared at the lower end of the central pier in all cases. The numerical simulations revealed that traveling wave effects have a beneficial effect on the displacement at the top of all piers. The explicit dynamic model was able to predict the failure modes and collapse process of the scaled bridge model. The plastic hinges emerging at the ends of the piers were considered the main failure modes, and the collapse process changed with different seismic wave excitations. Such tests and analyses can provide useful reference for the seismic-strengthening and anticollapse design of prestressed concrete continuous rigid-frame bridges with a long span.