Seismic response of bridge piers on elasto-plastic Winkler foundation allowed to uplift

Abstract

When the bridge piers with shallow foundation are subject to intensive earthquake excitations, uplift of foundations will occur and the foundation soil will partly become plastic. It is very difficult to use an accurate method to simulate the uplifting and yielding of supporting soil. An improved Winkler foundation model, which could be used to consider the uplift and yield, was employed in the analysis. The 1940 El Centro earthquake record is inputted to a rigid pier with shallow foundation so that the non-linear history response is obtained. From the non-linear analysis, it is concluded that the non-linear effect is very remarkable when uplifting and yielding of supporting soil are considered. Compared with the linear analysis, the stiffness of bridge pier–soil system degrades in each cycle after considering uplifting and yielding. It is shown that the non-linear analysis can get larger rotational angles and smaller bending moments compared with the linear analysis.