考虑板式橡胶支座时变状态的梁桥抗震性能演化机理研究

The girder bridge supported on elastomeric bearings is common in highway bridges, for which bearings are usually placed between girder and pier with no connection. Bridge maintenance records show that part bearings are not in ideal state due to operation diseases, including the shift of bearing, eccentric compression, over-compression or under-compression, aging, etc., and the supporting state varies with service duration, in which case the mechanical properties of bearings and the seismic performances of bridges will certainly be influenced. However, few researches have focused on this problem. This project thus aims to conduct research on the evolution mechanism of seismic performance for girder bridges by considering the time-varying state of elastomeric bearings, which mainly includes the following tasks: 1) Investigate the time-varying rule of the position, rotation angle, supporting force and material of elastomeric bearings, determine the actual state of the bearing with different service durations; 2) Conduct experimental and numerical researches on the mechanical properties and failure mechanism of bearings, in which the effect of single time-varying factor and the combined effect of multiple factors are successively considered; 3) Develop the multi-scale simulation method of girder bridges with the bearing in time-varying state, uncover the evolution mechanism of seismic performance and the failure mechanism of bridges. Then, develop a comprehensive index evaluation system for assessing the seismic performance of bridges, and propose rational and practical seismic mitigation measures. The research findings are promising to contribute to a further comprehensive seismic performance evaluation system for girder bridges with elastomeric bearings.

板式橡胶支座支承梁桥在我国公路桥梁中较为常见，其支座一般浮放于墩、梁之间。桥梁管养记录表明，部分支座因偏位、偏压、超（欠）压、老化等运营病害处于非理想状态，且病害程度随时间变化，进而会影响到支座力学性能与桥梁抗震性能，但目前少有针对这一问题的系统研究。因此，本项目拟开展考虑板式橡胶支座时变状态的梁桥抗震性能演化机理研究，主要包括：1）研究板式橡胶支座位置、转角、支承力与材料性能的时变规律，确定不同服役时长板式橡胶支座的实际状态；2）开展单一时变因素、多时变因素复合作用下的板式橡胶支座力学性能与失效破坏模式的试验与数值模拟研究；3）建立可考虑板式橡胶支座时变状态的梁桥多尺度模拟方法，揭示其抗震性能演化机理与震致失效破坏模式，建立抗震性能综合评价指标体系，提出合理可行的减灾控制方法。本项目有望为在役板式橡胶支座支承梁桥抗震性能评估理论的进一步完善提供依据。

本课题以国内常见的中小跨径梁式桥为背景，采用理论分析、数值模拟与模型试验相结合的研究方法，针对不同支承状态下的板式橡胶支座抗震性能变化规律，以及受此影响的梁式桥复杂地震响应及其减灾控制方法开展了研究。同时结合国内外在该领域的研究热点与趋势，对与板式橡胶支座类似的纤维增强橡胶支座开展了预探索。主要研究内容包括：.（1）对桥梁板式橡胶支座的支承状态进行了现场调研，研究了支座的偏位脱空、偏压转角病害程度及其变化规律，为开展后续研究提供了基础。.（2）对桥梁板式橡胶支座的运营病害进行了综述；开展了板式橡胶支座因运营病害导致的偏位、转角对支座力学性能影响的试验研究，量化了上述病害导致支座性能劣化的程度。同时，针对橡胶支座运营病害的普遍性，对橡胶支座内力的快速检测方法以及自愈合橡胶支座技术进行了探索。.（3）开展了考虑板式橡胶支座复杂力学行为的梁桥抗震性能演化机理与减灾控制方法研究，分析了初始偏位脱空的板式橡胶支座对梁桥抗震性能的影响。.（4）开展了近断层脉冲地震动、远场地震动作用下的多种滞回模型的等延性弹塑性反应谱的研究，初步探讨了基于反应谱的板式橡胶支座梁桥地震响应简化分析的可行性。.（5）根据行业关切与研究热点，对纤维增强橡胶支座的力学性能与工程应用进行了综述；自主设计研制了多种尼龙纤维增强橡胶支座，通过试验探讨了影响其力学性能的主要因素，并研究了将尼龙织物用于厚层橡胶支座的有益效果。提出了一种预应力厚层橡胶三维隔震装置，对其进行了理论分析与数值模拟，确定了其多项关键力学性能参数并验证了其三维隔震的有效性。.本项目目前已发表或录用的学术论文12篇，其中SCI收录2篇、EI收录6篇；授权国家发明专利1项、申请国家发明专利3项；授权软件著作权2项。以上研究成果为包括板式橡胶支座在内的多种桥梁隔震橡胶支座抗震性能评估理论的进一步完善提供了依据。