基于广义距离的大型桥梁状态评估研究

【作者】 高颖楠；

【导师】 黄方林；

【作者基本信息】 中南大学 ， 结构工程， 2008， 硕士

【摘要】 随着社会进步和土木工程技术的发展,越来越多的大型桥梁得到修建,为确保使用安全性和耐久性达到预期目标,对其进行状态评估愈显重要。本文主要研究基于广义距离的状态评估方法的应用以及利用主成分分析进行数据优化处理。具体内容如下:(1)回顾了大型桥梁状态评估的发展现状,系统介绍了状态评估的基本思路、内容、理论基础以及在桥梁状态评估中的常用方法,总结了桥梁状态评估中的若干问题及发展方向。(2)对列车活载过桥全过程进行了瞬态动力响应分析。将南京桥监测系统实测的列车轴重荷载作为一列匀速移动的集中活载作用在纵梁节点上,列车轴重作为质量单元加在南京桥纵梁相应节点上,在分析过程中将桥梁结构作为时变系统考虑。(3)提出了基于广义距离的桥梁状态评估方法,对南京桥南京联运营状态进行状态评估。由层次分析方法对南京联各测点的权重进行了分析,基于MATLAB平台编制程序,对列车过桥过程中南京联的工作状态信息进行隶属度分析,评估其运营状态。(4)鉴于大型桥梁监测数据冗杂,计算、评估需要很大工作量的情况,以南京联为例,利用主成分分析筛选变量的方法,对其监测数据进行处理,以最少的数据量来反映桥梁整体的状态,大大简化了评估工作,且数据处理前后的评估结果较为一致,验证了主成分分析的有效性。(5)利用ANSYS软件对南京联做了仿真分析,模拟其杆件损伤后的运营状态,并利用本文提出的方法对其进行评估,结果表明基于广义距离的评估方法能有效的反映桥梁的运营状态,是一种可行的评估方法。更多还原

【Abstract】 With the advancement of society and the development of civil engineering techniques, more and more large bridges have been constructed. In order to ensure the security and endurance match expectable objective, health monitoring and condition assessment for large bridges is more significant than ever.The work in this thesis is focused on a condition assessment based on generalized distance and processing the data by principal component analysis (PCA) method. The main contents are detailed as following:(1) Review state of arts of the condition assessment of large bridges. The essential ideas, contents, theory elements of the condition assessment and common method used in bridge condition assessment are systematically introduced. The problems and development trends of the condition assessment of the bridges are summarized.(2) Complete transient dynamic analysis in the whole course of train’s passing through, after programming the measured train axle loads from Nanjing Yangtze River Bridge (NYRB) monitoring system to the nodes of longitudinal girder as a set of moving concentration loads with constant velocity, and the train axle weight as mass element on the corresponding nodes. The calculation model of NYRB is considered as a time-varying system in the course of analysis.(3) Based on the generalized distance propose a condition assessment method for the overall evaluation of NYRB. The weights of measured points of Nanjing bank are evaluated by utilizing analytic hierarchy process (AHP). Based on the platform of MATLAB, the working condition information of the Nanjing unite is to be analyzed by the degree of membership so as to evaluate the working condition.(4) Calculation and evaluation need a large amount of work because of so much monitoring data for a large bridge. Taking Nanjing unite as an example, PCA can be used to process the monitoring data and obtain the condition of the whole bridge with the least data information so as to simplify evaluation work. Comparing with the results before and after data processing, the obtained evaluation results are consistent. So, this method is effective.(5) Utilize ANSYS software to make simulation analysis of Nanjing unite on the assumption of some members damaged. Then the condition of Nanjing unite is evaluated by using the method proposed in this thesis. The results show that the condition assessment method based on the generalized distance can effectively reflect the working condition of bridge, and is a feasible method of condition assessment.更多还原