基于模态参数的严寒地区高铁桥梁下部结构服役性能演变规律及状态评估方法研究

发布时间：2018-10-12 19:51

【摘要】：随着我国高速铁路的快速发展,严寒地区高铁桥梁工程也在不断规划与建设中,故该地区冻融作用对下部结构服役状态的影响已成为学术与工程界所关注热点。模态参数是下部结构服役性能的重要指标,可作为其状态评估的依据。冻融作用下,桥梁下部结构的自身刚度和约束条件发生改变,从而表现出模态参数的周期性演变。而既有的桥梁下部结构服役状态评估的研究成果中,鲜有考虑冻融作用这一因素的影响,对于严寒地区易导致评估结果的误判。本文以哈大高铁多跨简支梁桥为工程背景,通过理论分析、数值计算、现场试验等手段,主要做了以下研究工作:1.研究了针对高铁多跨简支梁桥的模态识别方法。通过对比分析冲击振动试验法和随机子空间法的原理及其在模态识别中各自的优势,提出了基于二者的高铁多跨简支梁桥模态识别流程,并对该流程进行了数值验证和现场试验研究。同时,分析了余振法、脉动法等传统测试手段在高铁桥梁模态识别中的困难点。2.分析了严寒地区高铁桥梁下部结构自振频率的演变规律。研究了高铁桥梁下部结构自振频率在冻融作用下演变的机理,并在冻融作用的数值模拟中得到了验证。对大量的实测样本数据进行了分析总结,探究了桥墩自振频率的分布规律及其冻融作用下的演变情况。3.提出了严寒地区高铁多跨简支梁桥下部结构服役状态评估方法。首先,基于大量的自振频率样本数据,利用回归分析法建立了桥墩自振频率的标准值公式,并考虑了冻融因素的影响。其次,选择桥墩服役状态指数SSI作为评估指标,依据相关规范和数值分析结果确定了该指标的安全限值。最后,根据该指标的限值提出了针对高铁多跨简支梁桥墩的评估准则,并总结了评估程序。
[Abstract]:With the rapid development of high-speed railway in our country, the high-speed railway bridge engineering in the cold area is planning and constructing constantly, so the influence of freeze-thaw action on the service state of the substructure in this area has become a hot topic in academic and engineering circles. The modal parameters are important indexes of the service performance of the substructure and can be used as the basis for the evaluation of the state of the substructure. Under the action of freeze-thaw, the stiffness and constraint conditions of the substructure of the bridge are changed, which shows the periodic evolution of the modal parameters. However, in the existing research results of bridge substructure service status evaluation, the influence of freezing and thawing is seldom considered, and it is easy to misjudge the evaluation results in cold regions. In this paper, based on the engineering background of the multi-span simply supported beam bridge of high-speed railway in Harbin and Dalian, the following research work has been done by means of theoretical analysis, numerical calculation, field test and so on: 1. The modal identification method for high-speed multi-span simply supported beam bridge is studied. By comparing and analyzing the principle of shock vibration test and random subspace method and their respective advantages in modal identification, the modal identification flow of high speed multi-span simple supported beam bridge based on them is proposed. Numerical verification and field test were carried out. At the same time, the difficulties in modal identification of high speed bridges by using the methods of residual vibration and pulsation are analyzed. 2. The evolution law of natural vibration frequency of the substructure of high-speed railway bridge in severe cold area is analyzed. The mechanism of natural vibration frequency evolution under freeze-thaw is studied and verified in the numerical simulation of freeze-thaw effect. A large number of measured sample data are analyzed and summarized, and the distribution law of natural vibration frequency of pier and its evolution under freeze-thaw action are discussed. In this paper, a method for evaluating the service status of the substructure of a high-speed multi-span simply supported beam bridge in severe cold area is presented. Firstly, based on a large number of natural vibration frequency samples, the standard formula of natural vibration frequency of pier is established by regression analysis, and the influence of freeze-thaw factors is considered. Secondly, the bridge pier service state index (SSI) is selected as the evaluation index, and the safety limit of the index is determined according to the relevant specifications and numerical analysis results. Finally, according to the limit value of the index, the evaluation criteria for the piers of multi-span simple supported beams are proposed, and the evaluation procedure is summarized.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U443.2

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