A Curves Approximated Multiple-Spring Model Seismic Response Simulation for Square-Section Steel Bridge Piers

Abstract

In this study, a seismic response simulation method based on the multiple-spring (MS) model and constitutive rules using curve approximation is proposed to predict nonlinear seismic response of steel bridge piers with rectangular cross-sections excited by bi-directional ground motions. A series of approximated curves and hysteretic rules are adopted to the nonlinear equivalent stress-strain relationship of spring elements distributed on the base cross-section of a thin-walled steel column. In this process，the strain of each spring can be calculated from the column's bi-directional displacements and the geometric coordinates, while the bi-directional horizontal restoring force can be obtained by the spring forces calculated by the springs' stress and tributary areas. To verify the accuracy of the proposed model，results of 6 uni-directional pseudodynamic tests and 3 bi-directional pseudodynamic tests are compared with numerical sirnulation results. The validity of the proposed method is demonstrated by good accuracy in restoring force and response displacement between the test results and numerical simulations.