关键词: 斜拉桥, 地震响应, 近断层地震, 脉冲模型, 等效模态法, 最小二乘法

Abstract: In order to investigate the effect of near-fault pulsed ground motions on cable-stayed bridges，the charac-teristics of near-fault pulsed ground motions are analyzed and are fitted to different numerical pulse models by means of the least square method． Then，the complex cable-stayed bridge is simplified into a system with single degree of freedom in longitudinal direction via the equivalent modal method，and the dynamic differential equations of the ca-ble-stayed bridge subjected to near-fault pulsed ground motions are therefore established and solved． Meanwhile，the analytical relationships between the top displacement as well as the bottom moment of the tower and the period as well as the amplitude of the pulse velocity are obtained to further reveal the general law of bridge seismic respon-ses varying with pulse parameters． Finally，finite element analyses of both single-tower and double-tower cable-stayed bridges are carried out to verify the accuracy of the proposed method． The results indicate that the method is of simplicity，feasibility and an acceptable error．

Key words: cable-stayed bridge, seismic response, near-fault ground motion, pulse model, equivalent modal method, least square method