合成地震动场相关（干）性对大跨桥梁地震反应的影响

发布时间：2018-01-11 04:13

本文关键词：合成地震动场相关（干）性对大跨桥梁地震反应的影响　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：笔者导师课题组研究采用合成地震动场作为计算大跨桥梁反应的非一致输入，揭示了非一致输入与一致、行波输入的差别，指出了研究非一致输入的重要性。本文进一步深入探讨合成地震动场中相关性、相干性不同对大跨桥梁地震反应的影响。收集一大跨悬索桥梁的设计资料，借助ANSYS软件建立了有限元分析模型；在收集的我国西部一活动断裂上发生的6.5级地震合成的地震动场中，取垂直和平行破裂线的共50组地表点对，逐一计算点对地震动时程间相关、相干系数，分析随相对震源主要凹凸体位置不同的差别。选取具有代表性的若干组点对作为大桥的地震反应输入，归纳输入地震动相关性、相干性不同对反应的影响。主要研究结果如下： 1.平行破裂线方向上点对间地震动相关系数、相干系数随点对与震源主要凹凸体的距离减小而减小；随着与主要凹凸体的距离减小，垂直破裂线方向点对间高频相干系数增大、低频相干系数减小，相关系数变化则无明显规律。 2.平行破裂面走向的大跨桥梁地震反应，相关系数、相干系数最小的地震动输入下，主梁顺桥向位移峰值、塔顶的均方根、主梁跨中及塔顶处横桥向位移峰值、主梁跨中和1/4跨处及塔顶的横桥向位移均方根值、主梁竖向位移均方根值、主梁轴力峰值和均方根值、塔底剪力等均会有最大值；即平行破裂面走向的桥梁布设在震源主要凹凸体处地震反应会最大，偏于不利；但主梁弯矩峰值及主梁跨中弯矩均方根值最小或相对最小。地震动输入相关系数、相干系数最大，主梁顺桥向位移均方根值、1/4跨处横桥向位移峰值、主梁跨中和1/4跨处竖向位移峰值均最大。 3.垂直破裂线方向点对输入桥梁计算地震反应，相干系数高频部分高、低频部分低的地震动输入下，主梁顺桥向位移峰值、主梁竖向位移均方根值、塔顶顺桥向位移峰值和均方根值、塔顶横桥向位移峰值、主梁弯矩峰值和均方根值、塔底剪力峰值和均值等均会有最大值；即垂直破裂面走向的桥梁布设在震源主要凹凸体处地震反应会最大，偏于不利。但主梁轴力峰值和均方根值最小。
[Abstract]:The author's research group used the synthetic ground motion field as the non-uniform input to calculate the long-span bridge response, and revealed the difference between the non-uniform input and the consistent, traveling wave input. The importance of studying non-uniform input is pointed out. In this paper, the effects of correlation and coherence on seismic response of long-span bridges in synthetic ground motion field are further discussed, and the design data of a long-span suspension bridge beam are collected. The finite element analysis model is established with the help of ANSYS software. In the ground motion field of a seismogenic earthquake with M = 6.5 occurring on an active fault in western China, 50 sets of ground surface point pairs of vertical and parallel rupture lines are taken to calculate the correlation between points to ground motion one by one. The coherence coefficient is analyzed with different positions of the main concave and convex bodies. Several representative pairs of points are selected as the seismic response input of the bridge and the correlation of the input ground motion is induced. The main results are as follows: 1. The correlation coefficient of ground motion between two points in the direction of parallel rupture line decreases with the distance between the point pair and the main concave and convex body of the source decreasing. With the decrease of the distance from the main concave and convex bodies, the high frequency coherence coefficient between the two pairs of vertical rupture lines increases, the low frequency coherence coefficient decreases, but the correlation coefficient changes irregularly. 2. Under the earthquake response of long-span bridge with parallel fracture plane strike, the peak displacement of the main beam along the bridge direction and the root mean square of the tower top under the input of ground motion with the smallest correlation coefficient and coherence coefficient. The peak displacement of the transverse bridge at the middle span of the main beam and the top of the tower, the root-mean-square value of the transverse bridge displacement of the main beam span and 1/4 span and the top of the tower, the root mean square value of the vertical displacement of the main beam, the peak value of axial force and the root mean square value of the main beam. The bottom shear force and so on will have the maximum value; That is to say, the bridge with parallel rupture plane will have the greatest seismic response at the main concave and convex body of the earthquake source, which will be unfavorable. However, the peak moment of the main beam and the root mean square value of the moment in the middle span of the main beam are the smallest or the least. The correlation coefficient of the ground motion input and the coherence coefficient are the largest, and the root-mean-square value of the forward bridge displacement of the main beam is equal to the peak displacement of the transverse bridge at 1 / 4 span. The peak value of vertical displacement of main beam span and 1/4 span is maximum. 3. The seismic response to the input bridge is calculated at the direction of the vertical rupture line. The vertical displacement of the main beam and the root mean square value of the vertical displacement of the main beam are calculated under the earthquake input of high frequency part with high coherence coefficient and low frequency part of the low frequency part. The peak displacement peak and root mean square value, the peak displacement peak value of tower top transverse bridge, the peak value of bending moment and root mean square value of main beam, the peak value of tower bottom shear force and the mean value of tower bottom shear will all have the maximum value. That is, the bridge with vertical fracture plane strike will have the largest seismic response at the main concave and convex body of the earthquake source, but the peak value of axial force and the root mean square value of the main beam are the smallest.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55

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