Influence of vertical component of near-fault ground motions on seismic behavior of RC bridge piers

Influence of vertical component of near-fault ground motions on the seismic behavior of RC bridge piers is an important issue concerned in the field of earthquake engineering recently. In this study, the nonlinear 3D FEM was used to construct the calculated model of bridge piers and to analyze the effect of near-fault vertical ground motions on seismic behavior of simple supported girder bridge piers which was commonly used presently in China railway. It was selected four earthquake records ( they are far-fault, near-fault, impulse and non-impulse) to be the input ground motions. The calculation results indicated that vertical component of ground motions have few of effect on seismic response of RC piers (< 2%) excited by the peak value of horizontal acceleration as 0.1 g or 0.2 g because that the piers worked in elastic behavior. However, the vertical ground motions have the most significant effect on seismic behavior of RC piers excited by the peak value of horizontal acceleration as 0.4 g, especially the P-Delta effect will remarkably increase the displacements at pier top. It is concluded that large-intensity near-fault ground motions will remarkably enlarge the failure probability of RC bridge piers.