Seismic evaluation method on shear strength models for round-end hollow piers of high-speed railway bridges

Round-end hollow pier has been widely used in China's high-speed railway (HSR) lines. Experimental studies have shown that the HSR round-end hollow pier may experiece bending shear failure in the transverse direction of bridge, which is a brittle failure. Although it is of great significance to clarify the shear strength model for HSR round-end hollow piers, their seismic shear performance and failure mode criterion are still unclear. Considering the existing seismic design codes of bridges are mostly applicable to ordinary bridge components, this paper proposes a shear strength model for HSR round-end hollow piers based on the truss model limiting equilibrium theory, and quasi-static test results. According to the proposed shear strength model, a bending-shear coupling numerical pier model was established using OpenSees. Then the accuracy of the proposed shear strength model is verified. The study results show that the proposed shear strength model can accurately obtain the shear strength of HSR round-end hollow piers compared with other evaluation methods. Besides, the numerical simulation results illustrate that the HSR round-end hollow pier is not prone to damage under the design seismic excitation. Corresponding to the extreme seismic excitation with the peak ground acceleration of 0.75 g, the HSR round-end hollow pier experiences bending shear failure, which can be accurately determine by the proposed shear strength model.