连跨悬索桥中间钢塔双重非线性极限承载力研究

Double Nonlinear Ultimate Bearing Capacity Analysis of Middle Steel Tower for a Multi-Span Suspension Bridge

以研究某悬索桥初步设计方案中间人字形钢桥塔在运营阶段的双重非线性极限承载力为目的,根据非线性有限元理论,阐述了同时考虑材料非线性和几何非线性的双重非线性薄壁箱形结构极限承载力的分析计算方法。根据边缘材料屈服和薄壁失稳出现的先后顺序,归纳了3种薄壁结构的塑性铰成因。采用通用有限元软件混合单元类型建立空间有限元模型,并根据其塑性铰成因归纳了桥塔达到极限承载力时的失效模式,以此对中间钢塔的运营安全性进行判断并提出相应的加强方案。

To study the double nonlinear ultimate bearing capacity of the middle chevron steel tower in the operation phase of the preliminary design of a suspension bridge,based on the nonlinear finite element theory,the analysis and calculation method of ultimate bearing capacity of thin-walled box structure is introduced considering both material nonlinearity and geometric nonlinearity.According to the sequence of edge material yield and thin-walled structures instability,the plastic hinge causes of three kinds of thin-walled structures are summarized.The spatial finite element model is established by using the general finite element software,and the failure mode of the bridge tower under the state of ultimate bearing capacity is concluded according to the cause of the plastic hinge,so as to evaluate the operation safety of the mediate steel tower and put forward the corresponding strengthening measures.