Influence of pier stiffness on the response of bridge abutments to seismic loading: a simplified model

The influence of pier stiffness on the shear on the abutments of a bridge subjected to seismic load in its transversal direction is herein analyzed. The feasibility of a simplified method previously proposed by the authors for the estimate of the abutments shear is investigated for different values of pier stiffness. Results from the simplified method are compared to time history nonlinear analyses results for different values of pier stiffness. The method is based on a plastic collapse analysis of the bridge subjected to abutment shear forces, deck inertia forces and the bending strength of the piers. Notwithstanding its simplicity the proposed method is able to take into account the changes of the pier characteristics giving a very good estimate of the maximum shear on the abutments for all values of pier stiffness.