Alternative Load Paths in Steel through-Truss Bridges: Case Study
Alternative Load Paths in Steel through-Truss Bridges: Case Study
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钢贯通桁架桥的替代荷载路径：案例研究
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Wenxing Zhou
中科院分区：
文献类型：
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作者：
S. Liu;F. Bartlett;Wenxing Zhou
传统的设计和评估程序通常将钢桁架桥划分为单荷载路径结构；然而，它们的历史表现显示出相当大的结构弹性。本文介绍了一项研究的大河桥，普拉特贯通桁架桥在卡尤加，安大略省，加拿大，系统地调查了荷载路径，而不是传统的假设在设计和评估。采用非线性有限元分析方法，对拆除单个桁架构件后的桥梁进行了备选荷载路径和相关关键构件及响应分析。考虑构件阻力的不确定性，进行了系统可靠性分析，评估了桥梁的失效概率。人们发现这座桥足以承受其名义上的恒载，即使在最坏的情况下拆除了一根端柱。结果表明，端底弦和垂吊架分别为临界张力弦和腹板。当存在多个备选负荷路径时，系统崩溃负荷的变异性远小于关键构件阻力的变异性。
Conventional design and evaluation procedures usually classify steel through-truss bridges as single-load-path structures; however, their historic performance has demonstrated considerable structural resiliency. This paper presents a study of the Grand River Bridge, a Pratt through-truss bridge in Cayuga, Ontario, Canada, that systematically investigates the load paths not conventionally assumed in design and evaluation. The bridge with individual truss members removed was analyzed using nonlinear finite-element analyses to investigate the alternative load paths and associated critical members and responses. A system reliability analysis was conducted to evaluate the failure probabilities of the bridge accounting for the member resistance uncertainties. The bridge was found to be sufficient to carry its nominal dead load, even for the worst case of removal of an end post. The end bottom chord and hanger vertical were found to be the critical tension chord and web member, respectively. If multiple alternative load paths exist, the variability of the system collapse load is much less than that of the critical member resistance.