塔梁弹性支座刚度对三跨连续悬索桥结构体系影响的研究

Research of Tower-girder Elastic Support Stiffness on Three-span Continuous Suspention Bridge Structure System

为研究塔梁竖向弹性支座刚度对三跨连续弹性支承钢箱梁悬索桥结构静动力特性的影响,以主跨926 m的浙江秀山大桥为依托,采用有限元通用软件midas Civil 2013建立4种方案模型,并对比4种方案结构静动力特性,提出合理的塔梁竖向弹性支座刚度控制因素。结果表明,随着塔梁弹性支座刚度增大,梁端和塔梁支座处钢箱梁转角、钢箱梁塔梁支座处和跨中位移也随之减小,但塔梁支座处钢箱梁的弯矩和应力会随之增大;成桥恒载状态下塔梁弹性支座反力也逐渐增大,其相邻的长吊索索力减小60%,但只有合适的塔梁弹性支座刚度,才可显著减小相邻长吊索的应力幅;钢箱梁底板应力和长吊索应力幅是塔梁弹性支座刚度取值的控制因素;结构基频有轻微减小,结构横向刚度有所降低。

In order to study the influence of tower-beam vertical elastic support stiffness on the structural static and dynamic characteristics of three span continuous elastic supported steel-box girder suspension bridge,based on Zhejiang Xiushan bridge with main span of 926 m,four models are established by using the finite element general software midas Civil 2013,the control factors are introduced,and the structural static and dynamic characteristics of the four schemes are compared.The results show that increasing the stiffness of the tower-beam elastic support can reduce the beam-end angle,the steel-box beam angle at the tower-beam support and the mid-span displacement of the steel-box beam,but the moment and stress of the steel-box beam at the tower beam support will increase.Under the dead-load state of the completed bridge,the reaction force and stress of the steel-box beam at the tower-beam elastic support also gradually increases,and the force of the adjacent long hanger will be reduced by 60%.However,only the appropriate stiffness of the tower-beam elastic support can significantly reduce the stress amplitude of the adjacent long hanger.In conclusion,it is proposed that the bottom plate stress of the steel box girder and the stress amplitude of the long hanger are the control factors for the stiffness value of the tower-beam elastic support.The fundamental frequency of the structure will decrease slightly,and the transverse stiffness of the structure will be reduced.