SEISMIC ANALYSIS OF MULTI-SPAN CONTINUOUS REINFORCED CONCRETE RIGID-FRAME ARCH-BRIDGE
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摘要: 以汶川大地震中倒塌的某钢筋混凝土刚架拱桥为例，采用杆端塑性铰模型、反应谱分析、弹性时程分析和动力弹塑性分析方法对其进行地震响应分析。根据两阶段抗震设计思想，确定表达两阶段水平的反应谱，选择了3组具有3个方向完整记录的地震地面加速度时程历史和1条人工地震波。研究结果表明：多跨连续钢筋混凝土刚架拱桥结构复杂，振型频率密集，振型参与质量分布离散；考虑桩-土-结构共同作用后，刚架拱桥在地震作用下结构内力和截面塑性转角增加；基础的非对称水平位移改变了结构的振动特性，显著增加基础水平抗推刚度较弱一侧主(次)拱腿的地震力和塑性变形，加剧了地震破坏作用。研究结论为多跨连续钢筋混凝土刚架拱桥抗震性能评估提供参考依据。
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关键词:
- 桥梁工程 /
- 钢筋混凝土刚架拱桥 /
- 反应谱分析 /
- 动力弹塑性分析 /
- 桩-土-结构共同作用
Abstract: The paper analyzed the seismic behavior of a reinforced concrete rigid-frame arch bridge which collapsed in Wenchuan earthquake using the spectral analysis method, the elastic dynamic analysis method and the elasto-plastic dynamic analysis method. According to the two-stage aseismic principle, 3 natural ground acceleration records and 1 artificial record were selected. The results show that: due to its structural complexity, the vibration frequencies of the multi-span continuous rigid-frame arch bridge are close to each other, and the modal participation mass is widely separated. Structural inter-forces and plastic rotation of RC section become larger when considering the soil-pile-structure interaction. The asymmetric longitudinal displacement of the foundation changes the vibration characteristics of the structure, and substantially increases the inter-forces and plastic deflections of main and minor arch legs on the foundation with weaker horizontal stiffness. The study may give a reference to seismic performance evaluation of multi-span continuous rigid-frame arch bridges. -
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