Abstract:In this paper, incremental dynamic analysis was used to investigate the effects of higher modes on seismic reposes of tall piers. Firstly the limitation of current design method focusing on conventional bridges was presented. Then the seismic performance of tall piers was investigated by incremental dynamic analysis method. The results show that with the contributions of higher modes of massive piers, multiple plastic zones are formed along the pier height under strong earthquake. The ultimate displacement at the pier top cannot be estimated by methods in current design codes, and the displacement varies outofphase with the curvature at the pier bottom. Further, the distribution patterns of shear force and bending moment along pier height are more complex than the linear and triangular distributions of conventional piers. Finally, some improvements for seismic design of tall piers are proposed.
