汶川地震中小跨桥梁损伤、破坏机理和位移控制方法研究

In the Wenchuan Earthquake, the slide between the girder and bearing of small and medium span bridges would incur comparatively large relative displacement between the a pier and a girder, which could eventually lead to typical earthquake damages of the concrete shear key, the expansion joint，the abutment and fall of girder. The research mainly focuses on the following areas: (1) the performance of the frictional sliding between the laminated-rubber bearing and the bottom of the main girder or the top of the pier; (2) the damage, failure mechanism and hysteretic model of concrete shear key; (3) the coupling effect model of bearing slide, the girder, the concrete shear key, expansion joint and abutment; (4) the multi-functional shaking table experiment of a typical small and medium span bridge model of Wenchuan Earthquake. Based on the research above, the earthquake damage and failure mechanism of small and medium bridges will be revealed, and the corresponding measures to control the displacement of the girder will also be proposed, hence improve the seismic capacity of the small and medium span bridges in China.

针对汶川地震中，中小跨度桥梁梁体与支座间的滑动，导致较大的墩、梁相对位移引起混凝土挡块、伸缩缝、桥台以及落梁等破坏的典型震害特点，主要研究：（1）板式橡胶支座与梁底或墩顶之间摩擦滑动性能；（2）混凝土挡块的损伤、破坏机理和恢复力模型；（3）地震下，支座滑动、梁体、混凝土挡块、伸缩缝及桥台相互耦合作用模型；（4）汶川地震典型中小跨度桥震害的多点振动台模型试验。在此基础上，揭示汶川地震中小跨度桥梁地震损伤、破坏机理，并提出相应的控制地震梁体位移的对策和措施，提升我国中小跨度桥梁的抗震能力。

针对汶川地震中中小跨度桥梁梁体与支座间的滑动，导致较大的墩、梁相对位移，引起混凝土挡块、伸缩缝、桥台以及落梁等破坏的典型震害特点，通过对板式橡胶支座与梁底或墩顶之间摩擦滑动性能、混凝土挡块的损伤、破坏机理和恢复力模型的研究，提出了考虑摩擦滑动面正压力、滑动速度的摩擦系数计算公式，建立了板式橡胶支座与钢板间摩擦的分析模型和混凝土挡块抗震性能的简化分析模型。以汶川地区典型中小跨度桥为背景，考虑混凝土挡块力学性能、板式橡胶支座与梁底的滑动效应，建立了精细有限元模型，应用数值模拟方法揭示了汶川地震中小跨度桥地震损伤、破坏机理。提出了板式橡胶支座与X形板弹塑性挡块联合使用的中小跨径板式橡胶支座梁桥新型隔震系统，结果表明地震过程中新型隔震系统大量耗散地震能量，有效控制墩梁相对位移，同时控制传递至下部结构的地震力，可以有效减轻桥墩及基础的损伤。最后，以一座典型中小跨度板式橡胶支座梁桥为背景，进行了大比例缩尺全桥振动台试验，采用振动台试验方法验证了数值模拟的结果和新型隔震系统的有效性，研究成果对提升我国中小跨度桥梁的抗震能力具有重要意义。.经过4年的工作，课题组照研究计划，完成了既定的研究任务，取得了预期的研究成果，发表学术论文24篇：(其中SCI期刊论文3篇，EI期刊论文13篇，国际国内重要会议论文4篇)。