【作者】 梁智垚；

【导师】 李建中；

【作者基本信息】 同济大学 ， 桥梁与隧道工程， 2007， 博士

【摘要】 近年来，随着西部大开发战略的实施，我国西部地区规划并建成了大量的公路和铁路线路，而跨越深谷、沟壑、江河的高墩桥梁往往是这些线路中的控制性工程。西部山区高墩桥梁结构通常属于典型的非规则桥梁，超出了现有国内外抗震设计规范的应用范围，无现成规范可循。基于此背景，本文结合我国西部山区高墩桥梁的结构特点，对非规则高墩桥梁抗震设计理论及设计方法进行了系统的研究，试图揭示非规则高墩桥梁在地震作用下结构需求和能力的复杂性。综合起来，本文主要做了以下几部分工作：(1)在查阅大量国内外文献的基础上，对桥梁抗震设计理论、抗震设计性能指标体系、位移延性能力计算方法、高墩桥梁抗震分析方法等方面的发展研究现状进行了系统的回顾与总结。(2)采用弹塑性梁柱单元和弹塑性纤维梁柱单元分别建立墩柱的两种计算模型，深入讨论了墩柱在地震作用下，塑性铰形成、塑性区扩展以及塑性转角、墩顶位移等结构地震需求，针对弹塑性梁柱单元模型中不同单元划分数量对墩柱地震需求的影响进行了比较分析。在此基础上，探讨了两种计算模型在墩柱地震需求计算时的适用性。(3)将增量动力分析应用于墩柱位移延性能力的计算，采用静力推倒分析方法和增量动力分析方法研究了不同墩高墩柱的破坏过程和位移延性系数，分析了地震荷载频谱特性、高阶振型、墩身质量效应、材料非线性水平等因素对单墩位移延性能力的影响，证明了增量动力分析作为一种求解墩柱位移延性能力方法的可行性和可靠性，最后对高墩位移延性能力计算方法、合理的性能指标和力学意义进行了讨论。(4)采用三种不同墩高、不同结构形式的桥梁结构计算模型，以结构振型质量参与系数为参考量，分别采用静力推倒分析方法和增量动力分析方法沿其横桥向或纵桥向计算结构屈服位移和极限位移。通过两种方法计算结果的比较，讨论了不同结构形式桥梁的损伤破坏过程，以及墩身质量和高阶振型参与对非规则高墩桥墩身节点位移、截面曲率及临界状态侧向荷载或惯性力分布模式等方面的影响。基于上述分析，提出采用截面曲率代替结构位移作为性能指标以确定非规则高墩桥梁结构相应的损伤状态。(5)根据抗震设计性能指标体系的研究和上述研究成果，考虑到墩身质量和高阶振型参与的影响，提出采用基于控制截面曲率的抗震设计方法作为非规则高墩桥梁的抗震设计方法。更多还原

【Abstract】 With the implementation of Western Development Program in recent years, a lotof highways and railways are planned and built in West China. The bridges with highpiers that span rivers, channels and valleys, belonging to typical irregular girderbridge, are key projects in main lines of communication. Because of given servicerange, seismic design criteria home and abroad are unavailable for these bridges. Theseismic design theory of irregular girder bridges with high piers is systematicallystudied to discover its complexity of structural ductility demand and ductility capacitysubjected to earthquake excitation in this dissertation. The main contents are asfollows:●Such aspects of research are reviewed as bridge seismic design philosophy,structural performance index system of seismic design, calculated method ofdisplacement ductility capacity and seismic analysis of bridges with high piers, basedon the comprehensive reading and understanding of related literature home andabroad.●Two analytical models of bridge pier are developed based on elastic-plasticbeam-column element and elastic-plastic fiber beam-column element. Structuralseismic demands such as formation of plastic hinge, expansion of plastic zone, plasticrotation and top displacement, are discussed in detail, and the influence ofelastic-plastic beam-column element divisions on seismic demand is analyzed andcompared. Finally, the applicability of two analytical models is discussed in seismicdemand analysis of tall bridge pier.●Increment Dynamic Analysis (IDA) is introduced into computing displacementductility capacity of piers, and IDA and pushover analysis are applied ondisplacement ductility index of different pier models. The influence of earthquakespectral character, higher vibration modes, self-mass of piers, material nonlinearitylevel on displacement ductility capacity of frame member is analyzed, and IDA isidentified as a feasible and reliable solution of displacement ductility index. After that,the computing means and mechanical explanation of displacement ductility capacityof high piers, proper performance index is investigated.●Take account of modal mass participation coefficients as reference variable, threebridge models with different height and structural style are created and analyzed to get yield displacement and ultimate displacement with IDA and pushover analysis alonglongitudinal direction or transverse direction of bridge. According to comparativeresults, the influence of higher vibration modes and self-weight on damage and failure,nodal displacement, cross-section curvature and lateral load or inertial forcedistribution at critical state is discussed. Instead of top displacement, cross-sectioncurvature is served as performance index to confirm its corresponding structuraldamage state of irregular girder bridges with high piers.●Based on performance index system of seismic design and research productionabove, Key Cross-section Curvature-Based Seismic Design philosophy is put forwardfor irregular girder bridges with high piers.更多还原