场地地震动及其非线性地震反应和大跨桥梁地震反应分析

发布时间：2018-10-25 13:03

【摘要】：大跨结构的地震响应是一个复杂的科学问题,它涉及场地输入地震动、场地地震反应分析和结构地震反应分析,本文围绕这3个环节开展了研究工作。这一研究对于建立简单、实用的场地地震动输入、场地地震反应分析方法和结构地震反应分析方法具有一定的参考价值。本文针对上述课题进行了系统研究,取得了以下研究成果：1.基于几何学仿射原理,将地震动衰减椭圆与潜在震源区凸多边形相交面积的计算算法转化为易于程序化编程的圆与凸多边形相交面积的计算算法,在保证精度的前提下大幅减少了编程工作量,提高了计算效率,改进了地震危险性分析计算程序,并给出了某场点的地震危险性分析的计算实例,为场地地震反应分析提供了高效、实用的地震动输入。2.针对传统一维等效线性化方法在强地震动作用下对厚软场地进行土层反应分析计算时高频响应被低估、峰值加速度偏低的缺点,提出用移动平均线来确定应变谱,并用Parzen's谱窗平滑应变谱曲线,然后引入弹性阀值理论,建立了考虑弹性阀值理论的频率相关等效线性化方法。通过与具有实测强震记录的厚软场地进行对比分析,结果表明此方法比传统一维等效线性化方法能更有效的模拟地震波高频成分在厚软覆盖层场地中的传播规律,同时揭示了传统一维等效线性化方法在分析厚软场地土层地震反应时存在较大的误差,为确定此类场地设计地震动参数提供了依据。3.基于地震波斜入射下成层弹性半空间频域求解方法和等效线性化理论,推导了地震波斜入射情况下二维等效剪应变求解公式,提出了一种地震波斜入射时二维水平成层介质的非线性地震反应分析方法。它将一维土层地震反应分析等效线性化方法拓展到二维土层地震反应分析中,建立了二维土层地震反应分析的等效线性化方法。对某二维水平成层场地地震波斜入射(SH波、SV波和P波)时的非线性地震反应进行了计算分析,揭示了成层介质场地地震反应随入射角变化而变化的规律。4.基于地震波斜入射下二维等效线性化方法和多源叠加粘弹性人工边界理论,建立了能同时考虑场地非线性、地形效应和土-结构动力相互作用的大跨结构动力反应分析计算方法。5.用上述建立的地震反应分析方法,利用ANSYS有限元软件对某连续刚构桥进行了SV波和P波斜入射下动力反应的计算分析。计算了考虑场地非线性情况下不同入射角、不同地形和不同场地刚度工况下连续刚构桥的动力响应,总结了连续刚构桥的动力响应随上述因素变化而变化的规律；同时计算了不考虑场地非线性情况下连续刚构桥的动力响应,并和考虑场地场地非线性的情况进行了对比分析。
[Abstract]:The seismic response of long-span structures is a complex scientific problem, which involves ground motion input, site seismic response analysis and structural seismic response analysis. This study has certain reference value for the establishment of simple and practical ground motion input, site seismic response analysis method and structural seismic response analysis method. This paper has carried on the systematic research to the above topic, obtained the following research results: 1. Based on the geometric affine principle, the algorithm for calculating the intersection area between the attenuated ellipse of ground motion and the convex polygon in the potential source region is transformed into an algorithm for calculating the intersecting area between the circle and the convex polygon, which is easy to program. On the premise of ensuring precision, the programming workload is greatly reduced, the calculation efficiency is improved, the calculation program of seismic hazard analysis is improved, and the calculation example of seismic hazard analysis at a certain site is given. For site seismic response analysis to provide an efficient, practical ground motion input. 2. In view of the shortcoming of the traditional one-dimensional equivalent linearization method that the high frequency response is underestimated and the peak acceleration is low, the moving average line is used to determine the strain spectrum. The strain spectrum curve is smoothed by the Parzen's window, and then the elastic threshold theory is introduced to establish the equivalent linearization method of frequency correlation considering the elastic threshold theory. The results show that the method is more effective than the traditional one-dimensional equivalent linearization method in simulating the propagation law of high frequency components of seismic wave in thick soft overburden ground by comparing with the thick soft site with measured strong earthquake records, and the results show that the proposed method is more effective than the traditional one-dimensional equivalent linearization method. At the same time, it is revealed that the traditional one-dimensional equivalent linearization method has a large error in analyzing the seismic response of thick and soft soil layers, which provides a basis for determining the design ground motion parameters of this kind of site. Based on the frequency-domain solution method and equivalent linearization theory of stratified elastic half-space under oblique incidence of seismic waves, a two-dimensional equivalent shear strain solution formula for oblique incidence of seismic waves is derived. A nonlinear seismic response analysis method for two-dimensional horizontal stratified media with oblique incidence of seismic waves is presented. The equivalent linearization method of seismic response analysis of one-dimensional soil layer is extended to the seismic response analysis of two-dimensional soil layer, and the equivalent linearization method of seismic response analysis of two-dimensional soil layer is established. The nonlinear seismic response of a two-dimensional horizontal stratified ground seismic wave with oblique incidence (SH wave, SV wave and P wave) is calculated and analyzed, and the variation of seismic response with incident angle in stratified medium is revealed. 4. Based on the two-dimension equivalent linearization method for oblique incidence of seismic waves and the theory of multi-source superimposed viscoelastic artificial boundary, the nonlinear field can be considered at the same time. Analysis and calculation method for dynamic response of large span structures with topographic effect and soil-structure dynamic interaction. 5. The dynamic response of a continuous rigid frame bridge under the oblique incidence of SV wave and P wave is calculated and analyzed by ANSYS finite element software using the seismic response analysis method established above. The dynamic responses of continuous rigid frame bridges with different incident angles, different terrain and different site stiffness are calculated, and the dynamic responses of continuous rigid frame bridges are summarized. At the same time, the dynamic response of continuous rigid frame bridge without considering site nonlinearity is calculated and compared with that of considering site nonlinearity.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TU435;U442.55

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