针对悬臂施工预应力混凝土箱梁合龙过程中底板崩裂问题,对其破坏机理和防治措施进行了研究。以某预应力混凝土连续箱梁桥为例,对其施工过程进行模拟,通过考虑材料非线性对底板开裂的过程进行仿真分析,并对底板崩裂的机理进行分析,在此基础上根据规范提出防治措施供设计应用。结果表明:由于合龙束孔道的影响,孔肋为受力最不利区域,在径向力作用下,孔肋的斜裂缝和撕裂裂缝是导致箱梁破坏的主要原因;在今后箱梁设计中,底板横向除应满足抗剪承载力外,孔肋尚需满足最小孔道间距的要求。
Abstract
Aimed at problem on failure of bottom plate of prestressed concrete box girder bridge during cantilever construction, its failure mechanism and prevention measure were studied. Taking a prestressed concrete box girder bridge as example, construction process of the box girder was simulated. Considering material nonlinear, the process of bottom plate crack was simulated and failure mechanism of bottom plate was analyzed. Based on it, according to code, prevention measure was proposed and was applied to practice. The results indicate that the rib is in the worst mechanical area. Failure of box girder is mainly induced by extending of diagonal and tearing crack of rib under effect of radial force. In the future design of box girder, transverse bottom plate should support anti-shear bearing capacity, rib should satisfy the requirement of minimum duct space.
关键词
桥梁工程 /
预应力混凝土箱梁 /
仿真分析 /
施工过程 /
破坏 /
材料非线性
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Key words
bridge engineering /
prestressed concrete box girder /
simulated analysis /
construction process /
failure /
material nonlinear
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中图分类号：
U448.35
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脚注
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基金
浙江省交通厅科技项目(2008H38)
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