曲线桥梁的简化分析方法及地震易损性研究

发布时间：2018-10-30 21:07

【摘要】：随着社会的发展,曲线桥梁在现代城市的交通网络中所占的比重日益增加。特别是曲线高架桥、立交桥的大规模建设与使用,使得曲线桥梁已经成为城市交通桥梁网络不可或缺的一部分。曲线桥梁在地震中的破坏将会直接影响城市桥梁网络的通行能力,给震后救援工作造成极大困难。对桥梁结构的地震易损性进行分析,是了解和评估桥梁结构的抗震性能的重要技术手段,在地震工程和防灾减灾领域已经广泛应用。但是,相比于直线桥梁,曲线桥梁的结构更为复杂,在地震作用下的地震响应及地震易损性分析更为困难。目前,广泛使用的有限元分析由于建模过程复杂、单元数量巨大、计算耗时长等问题,不适宜于城市大规模桥梁网络的快速建模及震后损伤快速评估。针对上述问题,本论文研究了曲线桥梁的简化建模方法,并对该类桥梁的地震易损性进行了研究。本文的研究工作及取得的成果如下:(1)利用OpenSees有限元分析软件,基于纤维单元建立了曲线桥梁的非线性有限元模型,数值模拟分析了曲线桥梁在不同方向、不同强度地震动输入下的响应特征,研究了桥梁结构墩顶、墩底和支座等关键构件的响应规律。(2)研究了曲线桥梁的破坏准则与结构损伤指标,通过对桥墩截面的弯矩-曲率和位移延性及支座变形分析的分析,研究了以墩底曲率延性系数、墩顶位移延性系数及支座极限变形为参数的桥梁结构损伤指标。(3)基于弹簧-杆系模型,研究了以刚性杆、弯曲弹簧、剪切弹簧、扭转弹簧为基本单元的曲线桥梁简化建模方法,建立了复杂有限元模型与简化分析模型的关联关系。研究表明,简化曲线桥梁模型的地震响应分析计算时间与纤维单元模型相比缩短了30%以上。(4)基于曲线桥梁简化模型,采用墩顶位移延性系数作为损伤指标对曲线桥梁的易损性进行了研究。研究表明,曲线桥梁顺桥向地震动输入时的易损性大于横桥向,且墩高是影响结构抗灾性能的关键参数。
[Abstract]:With the development of society, the proportion of curved bridge in modern city traffic network is increasing day by day. Especially the large-scale construction and use of curved viaduct and overpass make curved bridge become an indispensable part of urban traffic bridge network. The damage of curved bridge in earthquake will directly affect the capacity of urban bridge network and make the rescue work after earthquake extremely difficult. The analysis of seismic vulnerability of bridge structure is an important technical means to understand and evaluate the seismic performance of bridge structure. It has been widely used in the field of earthquake engineering and disaster prevention and mitigation. However, compared with linear bridges, the structure of curved bridges is more complex, and the seismic response and seismic vulnerability analysis are more difficult. At present, the widely used finite element analysis is not suitable for the rapid modeling of urban large-scale bridge networks and the rapid assessment of post-earthquake damage due to the complex modeling process, the large number of elements and the long calculation time. In order to solve the above problems, the simplified modeling method of curved bridges is studied in this paper, and the seismic vulnerability of this kind of bridges is studied. The research work and achievements are as follows: (1) the nonlinear finite element model of curved bridge based on fiber element is established by using OpenSees finite element analysis software, and the numerical simulation results show that the curved bridge is in different directions. The response characteristics of different intensity ground motion input are studied, and the response law of the key components such as the pier top, the pier bottom and the support are studied. (2) the damage criterion and damage index of the curved bridge are studied. Based on the analysis of moment curvature, displacement ductility and bearing deformation of pier section, the ductility coefficient of pier bottom curvature is studied. The damage index of bridge structure based on the displacement ductility coefficient of pier top and the limit deformation of support. (3) based on the spring-bar model, the rigid rod, bending spring and shear spring are studied. The simplified modeling method of curved bridge with torsion spring as the basic element is presented, and the relation between the complex finite element model and the simplified analysis model is established. The results show that the calculating time of seismic response analysis of simplified curved bridge model is more than 30% shorter than that of fiber element model. (4) based on the simplified model of curved bridge, The ductility coefficient of pier top displacement is used as damage index to study the vulnerability of curved bridges. The results show that the vulnerability of curved bridge to ground motion is higher than that of transverse bridge, and the pier height is the key parameter to affect the anti-disaster performance of the structure.
【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】：2017
【分类号】：U442.55

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