基于性能的高墩桥梁结构抗震性能分析

In the study field of performance-based earthquake engineering, evaluating the seismic performance of reinforced concrete bridge strucures with high piers has gained major attention in recent years. This research project will focus on the reinforced concrete bridge structure with hier piers. By using research methods such as model test, numerical simulation and theoretical analysis, the nonlinear dynamics model and the seismic performance limit state of the reinforced concrete pier, the more applicable intensity measure for estimating the seismic performance of the high pier，the numerical model considered intertive action of structure-fundation-soil, seismic performance analysis of bridge structure with high piers for performance-based earthquake engineering will be studied. By using model test and numerical simulation, the nonlinear dynamics model and the parametric description of the seismic performance of the reinforced concrete pier will be established. By using numerical simulation and statistical analysis, the more applicable intensity measure for estimating the seismic performance of the high pier will be studied based on probabilistic seismic demand analysis theory, and then the numerical model considered intertive action of structure-fundation-soil for bridge structure with high piers will be researched. Therefore, the key problems that lie in the procedure of evaluating the probabilistic seismic performance of the reinforced concrete bridge with high piers will be solved. The results of this research will offer theoretical and technical support for seismic design and seismic retrofit of the reinforced concrete bridge structure with high piers based-on performance-based earthquake engineering.

本项目拟以具有高耸桥墩的钢筋混凝土桥梁结构为研究对象，围绕桥墩的非线性动力分析模型、桥墩的抗震性能水平极限状态、考虑结构-基础-土相互作用的高墩桥梁结构的动力分析模型与抗震性能分析、设计地震动选取等开展模型试验、数值模拟和理论分析研究。揭示桥墩的非线性动力反应特性和抗震性能水平极限状态，建立桥墩的非线性动力分析模型和描述桥墩抗震性能极限状态的物理参数体系，在此基础上建立高墩桥梁结构的计算模型，研究基于性能的高墩桥梁结构抗震设计的设计地震动，从而解决基于性能的高墩桥梁结构抗震性能分析的关键问题，为高墩桥梁结构的抗震设计提供理论基础和技术支撑，具有重要的理论意义和工程价值。

伴随我国区域大开发和城镇基础设施建设工作的推进，大跨度高墩桥梁不断涌现。在我国这个地震多发国家，这类高墩桥梁的抗震性能研究具有重要的现实意义。.本项目以具有高耸桥墩的钢筋混凝土桥梁结构为研究对象，在高耸桥墩的精细化分析模型、高耸桥墩的抗震性能分析、地震动适用强度参数、考虑结构-基础-土相互作用的桥梁结构的整体建模和抗震性能分析等方面开展了模型试验、数值模拟和理论分析研究工作。研究工作和结果如下：.（1）通过振动台试验分析了钢筋混凝土空心桥墩的破坏机理，并在此基础上做了建模理论研究，结果表明，基于塑性铰的纤维单元模型在模拟高耸桥墩的性能时有较高的效率和精确度；采用多尺度建模理论则可以在分析效率和精确度之间找到平衡。采用能力谱方法可以评估桥墩的抗震性能。.（2）本研究发现：当选择适当的非线性振子参数时，采用非弹性位移响应谱值来预测桥墩的非线性地震响应具有较好效果，其作为近断层地震动作用下的桥墩抗震性能评估的地震动强度参数具有较好的适用性；在此基础上，针对高耸桥墩的高柔特性，提出了考虑高阶振型效应的高级地震动强度参数，其适用性通过增量动力分析得到验证，此高级地震动强度参数可以用来做桥墩的易损性分析。.（3）采用多尺度建模技术和无限元边界理论可以建立考虑土-结构-基础相互作用效应的桥墩和桥梁结构数值模型，并用来进行桥梁结构的抗震性能分析；推导了地下地震动输入的求解方法，在桥梁基础底下输入地下地震动激励可以精确评估桥梁结构的抗震性能。.本项目的研究成果对于高墩桥梁结构的抗震性能分析和评估具有重要的理论指导意义。