吊索猝断下钢桁拱桥的时变体系抗连续倒塌性能

TIME-DEPENDENT SYSTEMATIC PROGRESSIVE COLLAPSE RESISTANCE OF STEEL TRUSS ARCH BRIDGE UNDER HANGER FRACTURE

  • 摘要: 吊索猝断下在役钢桁拱桥体系的抗连续倒塌性能为结构应对非对称极端作用提供了必要的内部缓冲机制,材料劣化会改变体系抗连续倒塌过程中的再平衡格局。基于等效卸载的AP法模拟吊索猝断下应力波的传递与叠加效应,建立了吊索猝断下体系时变连续倒塌易损性评估方法。基于MATLAB/OpenSEES编制了单元纤维的时变演化参数组管理程序,建立了基于纤维宏单元的时变体系连续倒塌数值模拟方法,并通过动力试验数据验证了数值模拟的准确性;采用增量动力分析(IDA)法,开展了吊索猝断下钢桁拱桥的连续倒塌易损性分析,研究了材料劣化对吊索猝断下体系抗连续倒塌性能的影响规律。结果表明:吊索猝断会引起钢桁拱桥主要承载构件响应增大,其中猝断吊索相邻范围内受影响最大;材料劣化会降低钢桁拱桥体系的抗连续倒塌能力;基于IDA法的时变连续倒塌模型,可有效评估钢桁拱桥服役年限内的抗连续倒塌性能。

     

    Abstract: The progressive collapse resistance capability of a steel truss arch bridge system in service under hanger fracture provides an essential buffer mechanism for the structural response to against asymmetric extreme loads, and the rebalancing pattern during the systematic progressive collapse resistance will be altered due to material deterioration. The AP method, which based on equivalent unloading, simulates the transfer and superposition effects of stress waves during hanger fracture. One kind of means for evaluating the vulnerability of time-dependent progressive collapse of systems under hanger fracture is established. Based on MATLAB/OpenSEES, the time-dependent evolution parameter group management program of fiber elements is compiled, and the numerical simulation method for systematic time-dependent progressive collapse based on the fiber macro-element is established, and the accuracy of the numerical simulation is verified by the dynamic test results. The vulnerability to progressive collapse of steel truss arch bridges under hanger fracture is analyzed by the incremental dynamic analysis (IDA) method. The influence of material deterioration on the systematic progressive collapse resistance under hanger fracture on the fragility to progressive collapse resistance of steel truss arch bridges is investigated. The influence of material deterioration on systematic progressive collapse resistance under hanger fracture is studied. The analysis results show that hanger fracture leads to increases the response of main load-bearing components in the steel truss arch bridge, predominantly within the adjacent range of the hanger fracture. The material deterioration reduces the systematic progressive collapse resistance of the steel truss arch bridges. Additionally, the time-dependent progressive collapse model based on the IDA method can effectively evaluate the progressive collapse resistance of steel truss arch bridges during their service lives.

     

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