大跨径斜拉―刚构组合体系桥地震响应分析.pdf

Seismic Response Analysis of Long-SpanCable-binationWith Rigid-FramedSystemBridgeA Dissertation Submitted for the Degree of MasterCandidate:Cui TongsongSupervisor:Prof. Hu DalinChang’an University, Xi’an, ChinaI摘要斜拉桥作为一种拉索体系,比梁式桥的跨越能力更大,是大跨度桥梁的最主要桥型。随着斜拉桥跨度的增大、桥梁的整体柔性及构造的复杂性增加,大跨度斜拉桥的地震动研究俨然成为桥梁界最为关心、最具挑战性的课题之一。本文分析的斜拉桥是与刚构组合的新体系,结构复杂,且位于交通要道位置,所以分析它的地震响应是非常有必要的。本文总结了国内外研究成果为基础,对该实例桥主桥的动力特性和地震响应做了系统的研究分析。根据有限元理论并利用有限元分析软件MIDAS建立的空间分析模型,分析了桩-土-结构相互作用对结构动力特性的影响。分析结果显示考虑桩-土-结构相互作用对结构的动力特性有非常明显的影响。根据实例桥的结构和场地特点,选取了地震加速度、场地类别等相应的系数最终确定了标准的反应谱曲线,然后分别分析了沿该桥纵向、横向以及纵向+竖向和横向+竖向两种地震组合输入后的地震反应谱反应。分析结果显示竖向地震分量能对结构产生较大的影响,所以竖向地震动的作用在斜拉桥抗震设计中不能被忽略。由于反应谱是一种线弹性分析,不能考虑几何非线性的影响,所以本文选取了常用的El-Centro波对该桥进行动态的时程分析,该方法考虑了大跨柔性结构体系的几何非线性因素的影响,将此分析结果与反应谱分析结果进行对比,结果显示反应谱计算的结果偏大,所以应结合时程分析进行抗震验算。论文的研究成果可以作为同类桥梁抗震设计的参考依据,对其它类似桥梁地震反应分析也有一定指导意义。关键词:斜拉桥;桩-土-结构相互作用;反应谱;时程分析IIAbstractAs one of the cable systems, the cable-stayed bridge has more span capacity than girder bridge, and it is also one of the most importantbridge styles in long-span bridges. With the increase of the span, overall flexibilityand the complexity of the structure, the study of seismic response of the long-span cable-stayed bridge is the most concerned about and the most challenging issue in bridge engineeringindustry. Theinstance bridge which this paper analyzesis the new system bridge which cooperative with rigid-framed, the plicatedand what is more,this bridge is in trafficarteries location,soit is very necessaryto analysis the seismic response of this the basis ofthe Summarizes of theresearch results in domestic and foreign,this paper has done a systematic research and analysison the haracteristicsand the seismic paper established a spatial finite element model of the bridge which is finished by finite element analysis software MIDAS based on the theory of finite element, and considered the impact of the pile-soil-structure