腐蚀服役环境条件下斜拉桥拉索地震易损性

发布时间：2018-01-05 18:00

本文关键词：腐蚀服役环境条件下斜拉桥拉索地震易损性　出处：《大连理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：腐蚀问题是影响斜拉桥拉索运营状态下性能最重要因素之一。腐蚀会导致拉索截面削减,构件承载力下降,是服役环境下影响拉索承载力产生的主要因素。由腐蚀问题引起截面衰减的斜拉桥拉索在地震作用下安全性能大幅降低,因而研究腐蚀拉索地震易损性具有现实意义。目前的研究中对斜拉桥易损性的研究多针对结构整体和刚性构件,对腐蚀作用影响的拉索的地震易损性问题极少,对腐蚀影响的拉索安全性重视不够,同时对计算考虑随机性因素的腐蚀拉索承载力也没有成熟的方法。本文针对服役环境下的拉索腐蚀和地震响应问题,从拉索性能和易损性方面进行了以下研究：通过模拟综合考虑应力、温度、腐蚀环境等随机性因素的服役环境下拉索腐蚀环境参数的变化规律,建立拉索腐蚀随机性环境参数模型；综合考虑应力、温度、腐蚀环境以及随机性因素等对拉索腐蚀作用的影响,结合全寿命设计理论,提出腐蚀拉索截面变化率这一参数,并通过分段描述拉索在腐蚀作用下对拉索构件截面变化的影响,建立了一种将统计方法、加速腐蚀试验等相结合的方法以获取服役期内的该参数的全寿命时间关联曲线,为拉索寿命的评估和拉索在服役环境下的性能研究提供了基础和参考；综合考虑拉索腐蚀中的钢丝点蚀和拉索内钢丝径向非等值腐蚀问题,提出考虑点蚀问题和径向非等值腐蚀的修正Daniel模型,建立了考虑随机性因素的腐蚀拉索承载力评估模型,以此建立腐蚀拉索承载能力概率分析方法,并通过地震反应分析获取腐蚀拉索在地震作用下的需求值概率分布,建立了基于概率方法获取拉索地震易损性的分析方法。通过腐蚀拉索地震易损性分析方法分析拉索地震易损性,结果表明考虑腐蚀问题的拉索地震易损性与认为拉索保持完好状态的地震易损性存在较大差别,在严重腐蚀情况下拉索地震损伤问题不可忽略。说明在海洋大气等腐蚀性强的服役环境中,大跨度斜拉桥的抗震设计需对腐蚀问题造成的拉索能力削弱问题予以重视。
[Abstract]:Corrosion is one of the most important factors affecting the performance of cable in cable-stayed bridge. Corrosion will reduce the section of cable and reduce the bearing capacity of members. It is the main factor that affects the bearing capacity of cable in service environment. The safety performance of cable in cable-stayed bridge which is decayed by section caused by corrosion is greatly reduced under earthquake. Therefore, it is of practical significance to study the seismic vulnerability of corroded cables. At present, most of the researches on the vulnerability of cable-stayed bridges focus on the structure as a whole and rigid members, and the seismic vulnerability of cables affected by corrosion is very little. The safety of cables affected by corrosion is not paid enough attention, and there is no mature method to calculate the bearing capacity of corroded cables considering random factors. In order to solve the problem of cable corrosion and seismic response in service environment, the following researches have been carried out in this paper from the aspects of cable performance and vulnerability: stress and temperature are considered synthetically by simulation. The variation law of corrosion environmental parameters of cable in service environment with random factors, such as corrosion environment, is established, and the model of environmental parameters of cable corrosion is established. Considering the influence of stress, temperature, corrosion environment and random factors on cable corrosion, combined with the whole life design theory, the parameter of corrosion cable cross-section change rate is put forward. A statistical method is established by describing the influence of the cable section on the section change of the cable member under the action of corrosion. The combination of accelerated corrosion test and other methods to obtain the whole life time correlation curve of this parameter during the service period provides the basis and reference for the evaluation of cable life and the study of cable performance in service environment. Considering the pitting of steel wire in cable corrosion and radial non-equivalent corrosion of steel wire in cable, a modified Daniel model considering pitting and radial non-equivalent corrosion is proposed. The evaluation model of corrosion cable bearing capacity considering random factors is established, and the probabilistic analysis method of corrosion cable bearing capacity is established. The probabilistic distribution of the required values of corroded cables under earthquake action is obtained by seismic response analysis, and an analytical method based on probabilistic method for obtaining seismic vulnerability of cables is established. The seismic vulnerability of cables is analyzed by the method of seismic vulnerability analysis of corroded cables. The results show that the seismic vulnerability of cables considering corrosion is quite different from that of cables in intact state. The problem of seismic damage of cable in severe corrosion can not be ignored. It shows that it is in the environment of strong corrosive service such as oceanic atmosphere and so on. The aseismic design of long span cable-stayed bridge needs to pay attention to the problem of cable capacity weakening caused by corrosion problem.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.27;U442.55

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