几何非线性对沪通公铁两用长江大桥的影响  

Influences of geometric nonlinearity on Hutong combined highway and railway Yangtze river bridge

作　　者：张晔芝[1] 刘剑光[1] 张晓龙[1] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2015年第6期1387-1393,共7页Journal of Railway Science and Engineering

基　　金：中国铁路总公司科技研究开发计划课题(2013G001-A-2)

摘　　要：在建的沪通公铁两用长江大桥是一座超大跨度、超大体量、超大活载的公铁两用斜拉桥。采用U.L空间非线性有限元分析方法,以主跨跨中挠度最大的活载工况为例,研究3种几何非线性效应对该桥的变形和受力状态的影响。结果表明,3种几何非线性对桥梁的变形和受力状态的综合影响最大达到12.60%(增大);3种几何非线性效应中,斜拉索的垂度效应对于桥梁变形和受力状态的影响最大,达到7.73%,超过了大位移效应和梁柱效应的综合影响;用Ernst公式修正拉索弹模考虑拉索垂度效应的影响时,可用恒载+活载线弹性分析得到的索力,得到的结果较准确而避免了迭代计算;若用恒载索力修正拉索的弹模,将成倍夸大垂度效应的影响,因而是不可行的。Hutong Yangtze river bridge under construction is a combined highway and railway cable- stayed bridge with extremely large span,scale and live load. In this paper the U. L nonlinear FEM is used,and the influences of three types of geometric nonlinearity on the deformation and stress status of Hutong Yangtze river bridge are studied with the reference of largest mid- span deflection. The result shows the combined effect of the three types of geometric nonlinearity to the deformation and stress status of the bridge can increase by12. 60%.Among the three types of geometric nonlinearity,the effect of cable sag effect is the largest,reaching 7. 73%,exceed the combined effect of large displacement effect and girder- tower effect. If the cable elastic modulus are revised according to Ernst formula to considering the influence of the cable sag effect,the cable forces which computed through linear elastic analysis under dead load plus live load can be used. The results have enough precision thus the iterative computations are not needed. If the cable elastic modulus are revised using the cable forces only under dead load,the influence of cable sag effect will be multiple exaggerated,so it is not feasible.

关 键 词：几何非线性 公铁两用斜拉桥 垂度效应 大位移效应 梁柱效应 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]