悬索桥吊索断裂动力响应分析的有限元模拟方法研究

邱文亮，吴广润

摘   要：为精确模拟吊索断裂动力过程，基于拆除构件法，对模拟悬索桥断索动力过程的数值方法展开研究. 以某自锚式悬索桥为工程背景，详述了三种悬索桥吊索断裂动力过程模拟方法（瞬时刚度退化法、瞬时加载法、等效卸载法）的机理和特点，并对影响结构断索动力响应的因素展开分析. 研究表明：采用瞬时刚度退化法模拟悬索桥吊索断裂动力过程简单有效;悬索桥断索后结构的动力响应与限元分析模型中是否包含失效吊索单元、断索持续时间、断索过程中吊索拉力损失变化关系以及断索工况等因素密切相关.

关键词：悬索桥;断索;动力分析;数值模拟;拆除构件法;影响因素

中圖分类号：U448.25                        文献标志码：A

Research on Simulation Method of Dynamic Response Analysis

for Suspension Bridges Subjected to Hanger-breakage Events

QIU Wenliang，WU Guangrun？覮

（School of Civil Engineering，Dalian University of Technology，Dalian 116024，China）

Abstract：In order to accurately simulate the dynamic process of the cable rupture event， based on the alternate load path （ALP） method， the numerical simulation methods for dynamic analysis of suspension bridges subjected to hanger-breakage event are studied. Taking a prototype self-anchored suspension bridge as the background， the basic principles and characteristics of three methods （e.g.， the instantaneous stiffness degradation method， the instantaneous loading method and the equivalent unloading method） are illustrated. In addition， the influencing factors on structural dynamic effect of the collapse responses are quantitatively analyzed. The results indicate that the instantaneous stiffness degradation method is simple and effective to simulate the dynamic process of the hanger-breakage event. The hanger loss induced dynamic responses are closely associated with the influencing factors， such as the broken hanger elements in the finite element model， the duration and time-dependent tension loss function of the breakage process， and hanger loss scenarios.

Key words：suspension bridge;cable rupture;dynamic analysis;numerical simulation;alternate load path method;influencing factors

拉、吊索是缆索承重桥（斜拉桥、悬索桥以及中下承式拱桥）中最重要的承重构件，其基本力学性能和耐久性能对结构安全和正常使用产生巨大影响. 拉、吊索通常设计有防护措施，具有较高的安全系数，但是桥梁在长期服役期间，拉、吊索出现病害进行维修更换的案例层出不穷，极端荷载作用下桥梁发生断索的报道也屡见不鲜[1]. 例如，2011年10月，印度尼西亚Kutai Kartanegara悬索桥一根吊索断裂引发吊索连续断裂，最后结构整体倒塌[2]. 事故发生时工人正在对吊索进行维护保养，造成11人死亡、30多人失踪. 2019年10月，台湾宜兰县南方澳大桥一根吊索断裂，引发结构剧烈振动和相邻吊索连续断裂，最后主梁整体崩塌[3]. 缆索承重桥拉、吊索……