Abstract This study was motivated by the recent collapse of a tied-arch bridge with branched arch ribs. Hangers were successively broken when a heavy lorry crossed the bridge. In this article, the ultimate strength of tied-arch bridges, causes of hanger rope breakage and simulation of chain-reaction failure of hangers are studied for tied-arch bridges. Nonlinear finite element method analysis has clarified that this bridge model has sufficient ultimate strength. The hanger arrangement significantly affect the ultimate strength. The model with uniformly distributed hangers has higher ultimate strength and the hanger tensions are well balanced. Corrosion fatigue of wires could cause hanger rope breakage. The stress amplitude would be further amplified by secondary bending stresses, different safety factors, improper hanger tensions due to poor quality control, impact factors induced by moving vehicles, and effects of other vehicles. As the fatigue strength of corroded strands is significantly decreased, the estimated stress amplitude could cause hanger breakage. When a hanger breaks, the dead and live loads work impulsively, which are replaced by the equivalent static loads. The load is redistributed to the hanger next to the broken hanger, which induces the chain-reaction failure of hangers. This simulation method clarifies the mechanism of the bridge collapse.

中文翻译：

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系杆拱桥吊杆极限强度及连锁反应破坏

摘要 这项研究的动机是最近一座带有分支拱肋的系拱桥倒塌。当一辆重型卡车过桥时，衣架相继被打破。本文对系拱桥的极限强度、吊杆断绳原因及吊杆连锁反应破坏的模拟进行了研究。非线性有限元法分析表明该桥梁模型具有足够的极限强度。吊架布置显着影响极限强度。均匀分布的衣架模型具有更高的极限强度，并且衣架张力平衡良好。钢丝的腐蚀疲劳可能导致吊绳断裂。二次弯曲应力、不同的安全系数、由于质量控制不良、移动车辆引起的影响因素以及其他车辆的影响而导致的衣架张力不当。由于腐蚀钢绞线的疲劳强度显着降低，估计的应力幅可能会导致吊架断裂。当吊架断裂时，恒载和活载会脉冲工作，由等效静载代替。载荷被重新分配到破损衣架旁边的衣架上，导致衣架连锁反应失效。这种模拟方法阐明了桥梁倒塌的机理。由等效静载荷代替。载荷被重新分配到破损衣架旁边的衣架上，导致衣架连锁反应失效。这种模拟方法阐明了桥梁倒塌的机理。由等效静载荷代替。载荷被重新分配到破损衣架旁边的衣架上，导致衣架连锁反应失效。这种模拟方法阐明了桥梁倒塌的机理。