基于桥梁长期健康监测的数据特征分析与可靠度计算

发布时间：2018-08-02 19:09

【摘要】：在外在自然环境、荷载作用的综合影响下，桥梁的重要承重构件的承载能力会随着时间出现不同程度的衰减，影响桥梁的使用寿命。为了掌握桥梁的健康状况，针对大跨径桥梁，常采用长期健康监测系统，对桥梁进行实时监控。而随着监测数据的逐年累积，如何通过采集到的数据挖掘有用信息，进而应用到实际的桥梁设计、维护和状态评估当中去，成为了一个值得探讨研究的问题。本文采用数值计算方法对桥梁健康监测的数据进行分析，在大量数据累积的基础上，分析数据包含的深层信息。本文主要内容包括：（1）介绍了背景桥梁的工程概况以及针对该桥所设置的健康监测系统的主要布置形式。统计了实测得到的不同截面上温度以及应变数据的变化规律，采用统计学的相关方法，对实测应变数据进行相应的预处理。结合混凝土桥实测数据进行比对分析发现，混凝土桥内部的温度差要明显高于钢桥内部温度差。（2）通过傅立叶变换的计算方法，得出了钢箱梁桥实测温度数据与应变数据中包含两个相同的主要频率组成：12小时和24小时。和混凝土桥梁相同。提取不同频率对应的幅值，探讨了桥梁的纵桥向上截面同一部位变化特点。（3）通过小波分析，有效的滤除实测温度中所包含的噪声成分，并验证了和温度相同频率的应变组份是由日温度变化引起的。探讨了钢箱梁与混凝土箱梁截面温度场引起的温度应力在桥梁监测应力中所占的比重，混凝土桥截面不同位置的温度效应有很大差异，，但引起的温度应变占总应变很小一部分，而钢箱梁桥截面温度效应整体较为均衡，温度应变占总应变很大一部分成分，日温度效应引起的应变占整体的50%以上。（4）将实时应力数据引入可靠性评估，选取实测混凝土桥，采用一次二阶矩法以及Monte-Carlo法进行可靠度指标的计算。并通过对比计算结果，讨论一次二阶矩法对于实测数据可靠度计算的适用性以及精确性问题。
[Abstract]:Under the combined influence of external natural environment and load, the bearing capacity of the important load-bearing members of the bridge will decay with time, which will affect the service life of the bridge. In order to grasp the health status of bridges, a long term health monitoring system is often used for long span bridges. With the accumulation of monitoring data year by year, how to mine useful information through the collected data, and then apply it to the actual bridge design, maintenance and state evaluation, has become a problem worth studying. In this paper, the data of bridge health monitoring are analyzed by numerical method, and the deep information contained in the data is analyzed on the basis of a large amount of data accumulation. The main contents of this paper are as follows: (1) the engineering situation of the background bridge and the main layout of the health monitoring system for the bridge are introduced. The variation law of temperature and strain data on different cross-sections was calculated and the corresponding pretreatment of the measured strain data was carried out by using the statistical correlation method. By comparing and analyzing the measured data of concrete bridge, it is found that the temperature difference in concrete bridge is obviously higher than that in steel bridge. (2) the method of Fourier transform is used to calculate the temperature difference of concrete bridge. It is obtained that the measured temperature data and strain data of the steel box girder bridge contain two main frequencies which consist of two main frequencies: 12 hours and 24 hours. It's the same as a concrete bridge. The amplitudes corresponding to different frequencies are extracted, and the variation characteristics of the same part of the longitudinal section of the bridge are discussed. (3) the noise components contained in the measured temperature are effectively filtered by wavelet analysis. It is verified that the strain components of the same frequency as temperature are caused by the daily temperature variation. The proportion of temperature stress in bridge monitoring stress caused by temperature field of steel box girder and concrete box girder section is discussed. The temperature effect of different position of concrete bridge section is very different, but the temperature strain caused by the temperature strain is a small part of the total strain. However, the cross-section temperature effect of steel box girder bridge is relatively balanced, the temperature strain accounts for a large part of the total strain, and the strain caused by the daily temperature effect accounts for more than 50% of the total strain. (4) the real-time stress data are introduced into the reliability evaluation. The first order second moment method and Monte-Carlo method are used to calculate the reliability index of concrete bridge. The applicability and accuracy of the first-order second-moment method for calculating the reliability of measured data are discussed by comparing the calculation results.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446

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