刚性索自锚式悬索桥主缆锚固区局部应力分析

Local Stress Analysis at Anchorage Zone of Rigid Cable Self-Anchored Suspension Bridge

以平顶山建设路立交桥——刚性索自锚式悬索桥为工程实例,分别运用有限元计算程序Midas/Civil和Ansys建立其整体计算模型和边跨主缆锚固区梁段的局部计算模型,对锚固区进行空间局部应力分析,研究其受力状态,得出结论:箱梁绝大部分位置的应力均在规范允许范围内,且主梁压应力储备充足;箱梁主梁梁段切开截面端与顶板交接处的正中心位置顺桥向正应力和最大主拉应力均较大,局部超过规范要求,建议在桥梁设计和施工过程中考虑在边跨顶板中心位置配置压重或顶板纵向预应力钢束,防止箱梁顶板开裂;主缆锚固位置处的最大主压应力较大,锚固位置附近的最大主拉应力超限,需要在锚固位置附近局部加强或改变锚固方式;所有倒角部位在施工时应尽量平顺,避免应力集中。

The Pingdingshan Jianshe Road Overpass is taken as engineering example,which is a rigid cable self-anchored suspension bridge,and the finite element program Midas/Civil and Ansys are adopted to put up the whole calculational model and local model of anchorage zone of cable at side-span,and the local spacial stress analysis is made and the stress state is researched.The conclusions are that the stress at most of location of girder is within the standard,and the compress stress storage of girder is enough;the longitudinal normal stress and the maximum principle tensile stress are much more large,the local stress even exceeded the standard,these stresses are located at the central position of intersection between the section and top slab of girder.Such advice is proposed that the weights on the central position of top slab or longitudinal prestressed tendons should be allocated in the design and construction of bridge to prevent the top slab from crazing;the minimum principle compress stress at anchorage zone of cable is larger and the maximum principle tensile stress is out of limit nearby the anchorage zone,so the anchorage zone should be strengthened or the anchoring way could be changed;all of the chamfer should be smooth in construction to avoid the stress concentration.