Finite element simulation of an upliftable rigid frame bridge under earthquakes: Experimental verification

Under strong earthquakes, the shallow foundation bridge would experience partial or temporary separation of foundation from the support, hereafter termed as uplift. The uplift can activate rigid-like body movements and cut off the energy transfer of earthquake motions to the upper structure. However, most of the previous studies focus on the theoretical analysis using over simplified rigid body models, and some analyses often have appli-cable limitations because of their specific assumptions. Experimental research using a shaking table is time-consuming and expensive. In this paper, a finite element model (FEM) of an upliftable rigid frame bridge is developed and verified by a series of shaking table tests. The experimental bridge model is designed according to a similarity of 1:10 based on a viaduct in Auckland. The model has two kinds of foundation forms: fixed foundation and upliftable foundation, the corresponding FEM of the bridges with a fixed and an upliftable foundation is established. In the numerical investigation, the behavior of rocking of the structure due to the uplift between the foundation and the support was considered by Winkler springs. The proposed FEM was verified through the shaking table test results. It shows that the FEM is consistent with the experimental results and can be used to evaluation the displacement, acceleration and bending moment of bridges with an upliftable foundation.