【摘要】 为了探讨大跨悬索桥在动力激励下中央扣的作用,以四渡河悬索桥为研究对象,建立该大跨钢桁架加劲梁悬索桥的3种中央扣模式的空间动力计算模型,对其动力特性和在地震激励下的时程反应进行空间非线性分析。研究结果表明,中央扣提高了结构的反对称抗扭刚度和限制了结构的纵飘特性,同时加强加劲梁-主缆-主塔的动力耦合作用;1对柔性中央扣的设置方式对加劲梁的纵桥向位移和应力响应的影响均不利,因而是不可取的;而刚性中央扣和3对柔性中央扣的设置方式对限制加劲梁纵桥向振幅有较显著作用,但是由此导致结构地震应力响应大幅增加,因而从抗震设计角度设置中央扣是"有得有失"的。更多还原

【Abstract】 In order to investigate the function of central buckles of the long-span suspension bridge under dynamic loads excitation,taking the Sidu River Bridge,a suspension bridge with steel truss stiffening girders,as an example,the spatial dynamic finite element models for the Bridge with three types of central buckles were established with ANSYS software.Self-vibration behavior analysis and 3-D nonlinear time history analysis for the Bridge under seismic excitation were carried out.Analytical results show as follows: The central buckle raises the antisymmetrical torsion stiffness and restricts the longitudinal floating characteristic of the suspension bridge,and enhances dynamic coupling effect of the girder-cable-tower;a pair of flexible central buckles is not advisable to be adopted for seismic design of the suspension bridge because it has adverse effect on longitudinal displacement and stress response of the stiffening girder;the rigid central buckle and three pairs of flexible central buckles have significant effect on restricting the longitudinal vibration amplitude of the stiffening girder,however,thus making seismic stress responses of the structure increase greatly.Therefore the use of the central buckle has "merits and demerits" from the angle of seismic design of the suspension bridge.更多还原