考虑不同阻尼结构模型的矮塔斜拉桥地震响应分析

发布时间：2018-07-31 17:13

【摘要】：近几十年以来,预应力混凝土桥梁的跨度不断的增大,新型式的桥梁结构不断的出现,矮塔斜拉桥就是其中之一,它是介于预应力混凝土梁桥和斜拉桥之间的一种桥梁结构形式,这类大跨度桥梁由于是新近出现的,对于它们在地震作用下的受力变形等情况还没有充分的认识,因此研究矮塔斜拉桥在地震作用下的反应是十分必要的。众所周知,任何结构系统都具有振动阻尼,由于阻尼的存在,桥梁结构在振动时会产生能量的耗散,它对桥梁结构在地震作用下的反应有十分重要的影响,那么研究阻尼对矮塔斜拉桥地震响应的影响同样也是非常重要的。在进行地震响应反应谱分析时,采用不同的阻尼比桥梁结构的地震响应分析结果会有所不同,另外,在我国08抗震设计规范中规定,对于混凝土梁式桥而言,阻尼取值一般为0.05,而斜拉桥由于结构偏于柔性,阻尼比取值常为0.03,矮塔斜拉桥受力特点介于梁式桥与斜拉桥之间,其在进行地震响应分析时,阻尼比的取值应有别于传统的梁式桥和斜拉桥。对于大跨度矮塔斜拉桥这一类桥梁,运用反应谱分析方法分析其地震响应时,采用CQC振型组合分析并不能保证分析结果的精准性,因此反应谱分析法不能完全取代时程分析法;同时,在进行时程分析时,输入不同的地震波也会对计算结果产生很大的影响,并且抗震规范规定了,时程分析结果不能够反映结构的统计特性,而只是一个结构随机响应的样本,需要分析多个样本的结构进行统计,这样才能得到一个可靠的分析结果。鉴于以上原因,在进行矮塔斜拉桥地震响应分析时,同时采用两种方法进行分析,将两种分析方法的分析结果相互校核,最终得到地震反应分析结果。本文实际工程背景为宿州新汴河大桥,主要对其进行了下述几个方面的研究:(1)查阅与桥梁抗震方面相关的文献和资料,总结桥梁抗震领域的理论知识;(2)使用Midas/Civil2012结构分析软件,建立桥梁三维模型,分析新汴河矮塔斜拉桥的动力特性和振型对结构的影响;(3)运用反应谱法对新汴河矮塔斜拉桥在地震作用下进行线弹性地震响应分析,并比较不同阻尼比对反应谱分析结果的影响;(4)运用时程分析法对新汴河矮塔斜拉桥进行地震响应分析,并比较时程分析法和反应谱分析法的计算结果。
[Abstract]:In recent decades, the span of prestressed concrete bridges has been increasing, and new types of bridge structures have been emerging, among which the low tower cable-stayed bridge is one of them. It is a kind of bridge structure form between prestressed concrete beam bridge and cable-stayed bridge. Because this kind of long-span bridge is newly appeared, it has not fully understood their stress and deformation under earthquake. Therefore, it is necessary to study the seismic response of the cable-stayed bridge with low tower. As we all know, any structural system has vibration damping, because of the existence of damping, the energy of bridge structure will be dissipated during vibration, which has a very important effect on the response of bridge structure under earthquake. So it is also very important to study the influence of damping on the seismic response of cable-stayed bridge with low tower. In the seismic response spectrum analysis, the seismic response analysis results of bridge structures with different damping ratios will be different. In addition, in China's 08 seismic design code, for concrete beam bridges, The damping value of cable-stayed bridge is generally 0.05, but the damping ratio of cable-stayed bridge is 0.03 because of the flexibility of the structure. The stress characteristic of the cable-stayed bridge with low tower is between the girder bridge and the cable-stayed bridge. The value of damping ratio should be different from the traditional girder bridge and cable-stayed bridge. For the long-span and low-tower cable-stayed bridge, when the response spectrum analysis method is used to analyze the seismic response, the accuracy of the analysis results can not be guaranteed by using the CQC mode combination analysis, so the response spectrum analysis method can not completely replace the time-history analysis method. At the same time, when the time history analysis is carried out, the input of different seismic waves will also have a great influence on the calculation results, and the seismic code stipulates that the results of the time-history analysis cannot reflect the statistical characteristics of the structure. But it is only a sample of random response of structure, which needs to analyze the structure of multiple samples to make statistics, in order to get a reliable analysis result. In view of the above reasons, in the seismic response analysis of the cable-stayed bridge with low tower, two methods are used to analyze the seismic response. The results of the two methods are checked and the results of the seismic response analysis are finally obtained. The actual engineering background of this paper is the Xinbianhe Bridge in Suzhou, which is mainly studied in the following aspects: (1) consulting the literature and materials related to the earthquake resistance of the bridge, summarizing the theoretical knowledge of the seismic field of the bridge, (2) using the Midas/Civil2012 structural analysis software, A three-dimensional model of the bridge is established to analyze the dynamic characteristics of the cable-stayed bridge with low tower in Xinbianhe River and the influence of the vibration pattern on the structure. (3) the linear elastic seismic response analysis of the cable-stayed bridge with low tower in Xinbianhe River under earthquake is carried out by using the response spectrum method. The effects of different damping ratios on the response spectrum analysis results are compared. (4) the seismic response analysis of the cable-stayed bridge with low tower in Xinbianhe River is carried out by using time-history analysis, and the calculated results of time-history analysis and response spectrum analysis are compared.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U448.27

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