影响大跨悬索桥地震响应的敏感因素研究

摘 要：以四渡河悬索桥为研究背景，建立了该大跨钢桁架加劲梁悬索桥的空间动力计算模型，推导了基于Leger的LMM和拟静力位移概念的多支承激励下的非线性运动方程，在此基础上对该桥地震反应进行了空间非线性时程分析，研究了土-桩-桥相互作用和中央扣的设置方式对大跨悬索桥地震响应的影响。结果表明，土-桩-桥相互作用对悬索桥地震反应的影响与地震动输入方式密切相关，受水平地震波影响较大，而受竖向地震波的影响很小；一对柔性中央扣对加劲梁的纵桥向位移和应力响应的影响均不利，而刚性中央扣和三对柔性中央扣对限制加劲梁的纵桥向振幅有较显著作用，但是由此导致了结构地震应力响应显著增加。

Influence of Sensitive Factors on Seismic Response of Long-Span Suspension Bridge

Abstract: Based on the Large Mass Method of Leger and Pseudo-Static Displacement Conception, the nonlinear dynamic equilibrium equations of multi-support excitations for long-span suspension bridges were established. Taking Sidu River Bridge as an example, which is a suspension bridge with steel truss stiffening girder, the spatial dynamic finite element model for the bridge was established. Based on these, a 3-D nonlinear time history analysis for the bridge was investigated. Then effects of soil-pile-bridge interaction and central buckle on seismic response of long-span suspension bridge were studied. Analytical results show that effects of soil-pile-bridge interaction on seismic response of suspension bridge are closely related to the simulation ways of seismic ground motion and are greatly affected by the horizontal component but little affected by the vertical component of seismic waves; a pair of flexible central buckle has adverse effect on longitudinal displacement and stress response of stiffening girder, however rigid central buckle and three pair of flexible central buckle significantly restrict longitudinal amplitude of stiffening girder, meanwhile, these make seismic stress response of the structure increase greatly.