考虑土—结构动力相互作用的独塔斜拉桥地震响应

发布时间：2019-01-18 10:20

【摘要】：斜拉桥跨越能力较强,造型美观。作为交通运输的重要组成,斜拉桥一旦在地震中受到破坏或者损坏,会导致交通中断,带来较大的经济损失,我国地震的多发性决定了抗震分析在桥梁结构设计中的重要性。本文主要研究了土-结构动力相互作用对斜拉桥地震响应的影响,以一座独塔预应力混凝土斜拉桥为工程背景,采用有限元方法进行地震响应分析,主要进行了以下几个方面的工作：(1)对工程上常用的土-结构动力相互作用的物理模型进行总结和分析；(2)采用六弹簧法和全桩分散弹簧法两种土-结构动力相互作用模型,对考虑土—结构动力相互作用前后斜拉桥的自振特性进行分析。结果表明,在考虑了土-结构动力相互作用后,斜拉桥的基频和高阶频率均降低,部分高阶振型发生改变；(3)在纵向+竖向和横向+竖向两种地震波输入模式下,计算了基础固结模式和全桩分布弹簧模式下斜拉桥的地震时程响应,比较分析了土-结构动力相互作用对斜拉桥地震响应的影响,结果表明,若不考虑土-结构动力相互作用,斜拉桥的抗震设计将会偏于不安全；(4)计算比较了一致激励和多点激励下斜拉桥的地震时程响应,分析了不同地震波速下行波效应对斜拉桥地震响应的影响。计算结果表明,在独塔预应力混凝土斜拉桥抗震设计计算中,应该考虑土-结构动力相互作用对主塔和主梁的影响和行波效应对边墩的影响。
[Abstract]:The cable-stayed bridge has strong span ability and beautiful shape. As an important component of transportation, once cable-stayed bridge is damaged or damaged in earthquake, it will lead to traffic interruption and bring great economic losses. The earthquake frequency in our country determines the importance of seismic analysis in bridge structure design. In this paper, the influence of soil-structure dynamic interaction on the seismic response of cable-stayed bridge is studied. Taking a single-tower prestressed concrete cable-stayed bridge as the engineering background, the finite element method is used to analyze the seismic response. The main work is as follows: (1) summarize and analyze the common physical model of soil-structure dynamic interaction in engineering; (2) two kinds of soil-structure dynamic interaction models, six spring method and full pile dispersion spring method, are used to analyze the natural vibration characteristics of cable-stayed bridge before and after considering soil-structure dynamic interaction. The results show that when the soil-structure dynamic interaction is taken into account, the fundamental frequency and high order frequency of the cable-stayed bridge decrease, and some of the higher-order modes change. (3) the seismic time-history responses of cable-stayed bridges under the consolidation mode of foundation and the distributed spring mode of piles are calculated under the vertical and horizontal vertical seismic wave input modes. The effect of soil-structure dynamic interaction on the seismic response of cable-stayed bridge is compared and analyzed. The results show that the seismic design of cable-stayed bridge will be unsafe if the soil-structure dynamic interaction is not considered. (4) the seismic time-history response of cable-stayed bridge under uniform excitation and multi-point excitation is calculated and compared, and the influence of downlink wave effect of different seismic wave velocities on seismic response of cable-stayed bridge is analyzed. The results show that in the seismic design of prestressed concrete cable-stayed bridge with single tower, the influence of soil-structure dynamic interaction on the main tower and main beam and the effect of traveling wave on the side pier should be considered.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U448.27

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