考虑土—结构动力相互作用的三塔悬索桥地震响应分析

发布时间：2018-11-14 14:45

【摘要】：随着我国近年来地面交通的迅猛发展,需要大量大跨径的桥梁来通过宽广的海峡、大江或峡谷,而三塔悬索桥基于其独特的跨度优势及经济性,越来越受到工程师的青睐。而最近几年频发的强震所带来巨大的生命财产损失,也为我们敲响了警钟,对于大跨悬索桥的抗震分析应予以足够的重视。本文以某三塔悬索桥为工程背景,运用有限元分析方法,对其在土-结构相互作用下的地震响应进行了分析。本文主要工作如下：(1)介绍了几种常用的土-结构相互作用模型,并简单介绍了建立NIST六弹簧模型以模拟土-结构相互作用的基本步骤；(2)采用六弹簧法建立了三跨悬索桥考虑土-结构相互作用的模型,并对考虑与不考虑土-结构相互作用的两个模型进行了自振特性的比较分析。结果表明悬索桥在考虑了土-结构相互作用之后,会影响到桥梁整体的刚度,使其刚度降低；(3)对考虑与不考虑土-结构相互作用模型运用一致激励法,计算了三塔悬索桥的地震响应,对结果进行了分析比较,讨论了土-结构相互作用对三塔悬索桥地震响应的影响。结果表明,考虑土-结构相互作用后,对内力的影响较大；(4)采用多点激励法,对考虑土-结构相互作用的模型进行了行波效应下的地震响应时程计算,比较分析了不同视波速下行波效应的影响,并对照一致激励的结果进行了分析。结果表明,行波效应对大跨悬索桥的影响随波速的不同有较大的波动,实际工程中应根据场地地质条件选取合适的视波速。
[Abstract]:With the rapid development of ground transportation in China in recent years, a large number of long-span bridges are needed to pass through wide straits, rivers or canyons, while three-tower suspension bridges are more and more favored by engineers because of their unique advantages in span and economy. In recent years, the frequent strong earthquakes have brought huge loss of life and property, which has also sounded the alarm for us. The seismic analysis of long-span suspension bridges should be paid enough attention to. In this paper, the seismic response of a three-tower suspension bridge under soil-structure interaction is analyzed by using finite element method. The main work of this paper is as follows: (1) several commonly used soil-structure interaction models are introduced, and the basic steps of establishing NIST six-spring model to simulate soil-structure interaction are briefly introduced. (2) A three-span suspension bridge model considering soil-structure interaction is established by using the six-spring method, and the natural vibration characteristics of the two models with or without soil-structure interaction are compared and analyzed. The results show that the overall stiffness of the suspension bridge will be affected and the stiffness will be reduced after considering the soil-structure interaction. (3) the seismic response of the three-tower suspension bridge is calculated by using the consistent excitation method for considering and disregarding soil-structure interaction, and the results are analyzed and compared. The effect of soil-structure interaction on seismic response of three-tower suspension bridge is discussed. The results show that the influence of soil-structure interaction on internal force is great. (4) the seismic response time history of the model considering soil-structure interaction is calculated by using multi-point excitation method, and the effect of downlink wave effect at different apparent wave velocities is compared and analyzed. The results of consistent excitation are analyzed. The results show that the influence of traveling wave effect on long-span suspension bridge has great fluctuation with different wave velocities, and the appropriate apparent wave velocity should be selected according to the geological conditions of the site in practical engineering.
【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;U448.25

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