波形钢腹板PC连续刚构桥结构动力学与地震反应分析

发布时间：2018-04-09 19:18

本文选题：桥梁抗震　切入点：波形钢腹板　出处：《东南大学》2015年硕士论文

【摘要】：我国处于两大地震带之间,是个震害较为严重的国家。近年来,波形钢腹板PC组合箱梁结构在桥梁工程中的应用愈来愈广泛,了解其结构动力特性及在地震作用下的反应有着十分重要的意义。作为一种快速简便的地震响应分析方法,Pushover(静力弹塑性)分析成为目前抗震研究的热点。本文以一座波形钢腹板PC连续刚构桥为背景,研究了Pushover分析法在桥梁结构地震响应分析中的应用。从桥墩构件到全桥结构,对这种分析方法的应用进行了详细的阐述。系统地总结了Pushover分析法的基本原理、基本假定及实现过程。指出了影响分析结果的两大重要因素：侧向力分布模式的选取和目标位移的计算方法。并详细介绍了用能力谱法评估结构抗震性能的关键步骤。对薄壁箱形墩模型,选取两种侧向力分布模式(均匀分布模式和基本振型分布模式)进行Pushover分析。结果表明顺桥向和横桥向的结构能力曲线(墩底剪力-墩顶位移关系曲线)变化规律基本一致；同一结构在不同的侧向荷载分布模式下结构能力曲线有所差异。根据求得的性能点的位置评估了薄壁箱形墩结构的抗震性能。对其进行反应谱分析,并将结果与Pushover分析作对比。结果显示两种分析方法下的结构地震响应基本一致,说明Pushover分析方法适用于该结构并且简便高效。采用Ritz向量分析法对一座波形钢腹板PC连续刚构桥进行结构动力特性分析,以两种工况(工况一：主要振型确定的侧向荷载+自重+二期恒载；工况二：前70阶振型确定的侧向荷载+自重+二期恒载)分别就顺桥向和横桥向进行全桥结构Pushover分析。结果表明,在这两种不同工况下结构的能力曲线基本一致,由性能点表征的结构地震响应也基本吻合。说明采用振型贡献率较高的主要振型来确定侧向荷载分布模式是可行的,在评价桥梁结构的抗震性能方面可以达到选取较多阶振型进行分析的效果。介绍了非线性动力时程分析法及选波方法,并求得全桥结构地震响应。各墩墩顶位移响应与Pushover分析结果的对比表明,Pushover分析结果与时程分析结果较为接近,并且略有偏大。说明了对于课题背景桥,基于Pushover分析的结构抗震性能评估偏于安全。
[Abstract]:China lies between the two major seismic zones and is a country with severe earthquake damage.In recent years, the application of corrugated steel web PC composite box girder structure in bridge engineering is more and more extensive. It is of great significance to understand the dynamic characteristics of the structure and its response to earthquake.As a fast and simple method for seismic response analysis, Pushovere (static elastoplastic) analysis has become a hot topic in seismic research.Based on a PC continuous rigid frame bridge with corrugated steel web, the application of Pushover analysis method to the seismic response analysis of bridge structure is studied in this paper.The application of this analysis method is described in detail from pier member to whole bridge structure.The basic principle, basic assumption and realization process of Pushover analysis are summarized systematically.Two important factors affecting the analysis results are pointed out: the selection of lateral force distribution model and the calculation method of target displacement.The key steps to evaluate the seismic performance of structures by capacity spectrum method are introduced in detail.For thin-walled box pier model, two kinds of lateral force distribution modes (uniform distribution mode and basic mode distribution mode) are selected for Pushover analysis.The results show that the variation law of the structural capacity curve (the shear-pier top displacement relation curve) is basically the same, and the structural capacity curve of the same structure is different under different lateral load distribution modes.The seismic performance of thin-walled box pier structure is evaluated according to the location of the obtained performance point.The reaction spectrum was analyzed and the results were compared with Pushover analysis.The results show that the seismic response of the structure under the two methods is basically the same, which indicates that the Pushover analysis method is suitable for the structure and is simple and efficient.The structural dynamic characteristics of a corrugated steel web PC continuous rigid frame bridge were analyzed by Ritz vector analysis method.Case two: the first 70 modes determined by lateral load dead load for the second phase) the whole bridge structure Pushover analysis is carried out on the straight bridge direction and the transverse bridge direction respectively.The results show that the capacity curves of the structures under these two different working conditions are basically the same, and the seismic responses of the structures characterized by the performance points are basically consistent.It is proved that it is feasible to determine the lateral load distribution mode by using the main modes with higher contribution rate of vibration modes, and the seismic behavior of bridge structures can be evaluated by selecting more than one vibration mode for analysis.The nonlinear dynamic time-history analysis method and wave selection method are introduced, and the seismic response of the whole bridge structure is obtained.The comparison of displacement response of pier top with that of Pushover analysis shows that the results of pushover analysis are close to those of time-history analysis and are slightly larger.It shows that the seismic performance evaluation of the structure based on Pushover analysis is more safe than that of the background bridge.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3;U448.23

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