部分斜拉桥斜拉索锚固和传力安全性分析

Analysis of the anchoring and transmission force safety for cable of a partial cable-stayed bridge

为研究斜拉索锚固区应力分布状态和箱梁悬臂端处剪力在横隔板与翼缘板之间的分配情况,本文以大跨度曲线预应力混凝土部分斜拉桥为背景,采用有限元软件MIDA SFEA分别对斜拉索首索附近梁段和尾索附近梁段建立空间实体有限元模型,分析了首索索力最大、尾索索力最大和尾索处主梁底板最不利3种工况下主梁在有无锚固区时的应力分布,探讨了在荷载标准组合和特殊荷载作用下索梁锚固区剪力的分配情况。结果表明:主梁在拟定工况下应力状况较好,压应力水平良好,拉应力水平仅在锚固区略超限。斜拉索锚固区竖向剪力由横隔板和翼缘板共同承担,主梁设计应按横隔板和翼缘板共同抗剪设计,且横隔板承担剪力不超过50%。

A large-span curved prestressed concrete partial cable-stayed bridge was used to study the stress distribution of the cable anchorage zone and the shear distribution between the diaphragm and flange plate with the cantilever end of a box girder.MIDAS FEA finite element software was used to establish the spatial entity finite element models of the girder segments at the first cable and last cable.The stress distribution of the box girder with or without an anchorage zone was analyzed under three conditions,which were the maximum cable force of the first cable,the maximum cable force of the last cable and the most unfavorable load of the bottom flange plate of the box girder in the last cable.The shear distribution of the cable-girder anchorage zone was discussed under the standard combination of load and special load action.The result shows that,under the drafted working condition,the box girder has good stress distribution,only the tensile stress in the anchorage zone is slightly beyond the limit level,and the pressure stress is normal;the diaphragm and flange plate together bear the shear force,with the diaphragm bearing less than 50%of the shear force,which should be considered in bridge design.