基于不同输入方向的斜交桥最不利地震动响应研究

发布时间：2018-05-09 20:49

本文选题：斜交桥 + 最不利地震响应　；参考：《北京交通大学》2014年硕士论文

【摘要】：摘要：由于地震作用的随机性和复杂性,在对结构进行抗震计算时,很难确定地震波准确的输入方向。斜交桥梁的平面不规则性导致了弯扭耦合效应,使得最不利地震输入方向更难以确定。因此深入研究斜交桥在任意角度输入下多向地震作用反应,提出斜交桥简化的地震反应计算理论,保证斜交桥在地震中的安全性是非常有意义的。本文首先综述了有关斜交桥最不利地震响应的研究成果；在此基础上,通过考虑斜度、跨数以及桥台碰撞效应等因素建立不同特性的斜交桥有限元数值分析模型,对斜交桥地震动最不利响应问题展开深入研究。主要研究内容和所得结论如下： 1、采用考虑地震空间效应的水平双向正交地震输入方式,通过对不同特性的斜交桥有限元数值分析模型作基于不同输入方向的非线性时程分析,研究了地震输入角度与不同特性斜交桥地震内力的关系：在双向地震作用下,地震输入角度对斜交桥上部桥跨位移和墩底地震内力影响较大,部分地震响应随着输入角度呈近似正余弦规律变化,相同响应量纵横向的变化规律相反。按常规方向进行时程分析所得响应量的最值与理论计算的最值相差较大,可能会大大低估斜交桥某些响应量值。 2、借鉴目前被国内外相关规范建议的反应谱分析地震反应组合方法,包括SRSS、100/40和100/30等三种组合方法计算斜交桥最不利地震响应,通过低估概率来评判三种组合方法的安全性,结合不同角度输入时程分析,合理提出计算不同特性斜交桥最不利地震响应的简便方法。 3、基于静力弹塑性分析方法的思想,提出了通过两正交方向Pushover结果进行组合,以合成多角度能力谱曲线,再与折减的需求谱曲线绘制在同一坐标轴中,以模拟斜交桥多角度Pushover分析,探讨了不同斜率的斜交桥在多维输入下的需求-能力关系。
[Abstract]:Abstract: due to the randomness and complexity of seismic action, it is difficult to determine the accurate input direction of seismic wave in seismic calculation of structures. The plane irregularity of skew bridge leads to the coupling effect of bending and torsion, which makes the direction of the most unfavorable earthquake input more difficult to determine. Therefore, it is very meaningful to study the multi-direction seismic response of the skew bridge under any angle input, and to put forward the simplified seismic response calculation theory of the skew bridge to ensure the safety of the skew bridge in the earthquake. In this paper, the research results of the most unfavorable seismic response of skew bridge are summarized, and based on this, the finite element numerical analysis model of skew bridge with different characteristics is established by considering the factors such as slope, span number and collision effect of abutment. The most unfavorable response of skew bridge ground motion is studied in depth. The main contents and conclusions are as follows: 1. The horizontal and bidirectional orthogonal seismic input method considering seismic spatial effect is adopted. The nonlinear time-history analysis based on different input directions is made for the finite element numerical analysis model of skew bridge with different characteristics. The relationship between seismic input angle and seismic internal force of skew bridge with different characteristics is studied. Under the action of bidirectional earthquake, the influence of seismic input angle on the displacement of the upper bridge span and the seismic internal force at the pier bottom of the skew bridge is great. Some of the seismic responses vary approximately with the input angle, but the variation of the same response is opposite in the longitudinal and horizontal directions. The maximum value of the response obtained by the conventional time-history analysis is quite different from that of the theoretical calculation, and some response values of the skew bridge may be greatly underestimated. 2draw lessons from the response spectrum analysis combination method, which is suggested by relevant codes at home and abroad, including SRSS 100 / 40 and 100 / 30 combination methods to calculate the most unfavorable seismic response of skew bridge, and evaluate the safety of the three combination methods by underestimating the probability. A simple and convenient method for calculating the most unfavorable seismic response of skew bridge with different characteristics is put forward by combining the time history analysis of different angles. 3. Based on the idea of static elastic-plastic analysis, a combination of two orthogonal direction Pushover results is proposed to synthesize the multi-angle capability spectrum curve, and then draw the reduced demand spectrum curve in the same coordinate axis. Based on the multi-angle Pushover analysis of the skew bridge, the demand-ability relationship of the skew bridge with different slopes under the multi-dimensional input is discussed.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55

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