多次地震作用下跨海桥墩全寿命抗震性能分析

发布时间：2018-07-03 10:01

本文选题：跨海桥墩 + 多次地震　；参考：《大连理工大学》2015年硕士论文

【摘要】：跨海桥梁具有建设投资大、设计服役期长、工作环境恶劣并且面临较高的地震作用风险等特点。近年来随着中国对基础设施建设的需求和投入不断加大,跨海桥梁工程的建设也日趋繁荣。桥墩作为最重要的受力部件,在跨海桥梁服役的全寿命过程中保持安全可靠的性能至关重要。历史地震资料和国内外学者的研究表明,跨海桥墩在服役过程中可能会受到严重的氯离子腐蚀作用和多次地震作用。针对于此,本文主要进行了以下几个方面的研究工作：(1)基于历史地震统计资料、地震危险性分析模型和统计学原理讨论了不同形式的多次地震作用在结构服役期内出现的概率。分析结果表明结构在其服役的全寿命周期内遭遇两次或者两次以上完全不相关的地震或地震序列的概率是极低的,但是其遭遇一次包含多个地震动的地震序列的概率是非常大的,因此有必要对这种地震序列作用情况进行研究。(2)在国外学者提出的地震序列构造方法基础上通过从PEER强震数据库引入10组相同台站记录的实际主余震记录构造出更加符合真实情况的地震动序列；在进行非线性动力时程分析时将一组地震动序列连续输入到桥墩模型中以考虑其在多次地震作用下的累积损伤情况。(3)讨论了对跨海桥墩耐久性影响最大的氯离子腐蚀作用并基于Life-365软件分析了海洋环境所使用的高性能混凝土中钢筋的锈蚀情况。计算结果表明尽管跨海桥墩采用了高性能混凝土和阻锈剂等防护措施,但在其长达百年的服役过程中仍然难以避免受到氯离子腐蚀作用,导致钢筋开始锈蚀并进而影响桥墩的抗震性能。(4)基于增量动力分析和地震易损性分析方法对桥墩在服役过程中的未腐蚀阶段、钢筋开始锈蚀后的桥墩服役第60年、80年和100年进行了分析,同时比较了桥墩在单独主震和地震序列作用下的反应差异。分析结果表明,在轻微破坏状态时,桥墩基本保持线性工作状态,此时其受服役时间和地震序列作用的影响不大；在中等破坏、严重破坏和完全破坏状态时,桥墩进入了塑性状态,此时服役时间和地震序列作用对桥墩的墩顶位移反应和易损性曲线有很大的影响,桥墩更容易进入危险状态。
[Abstract]:Cross-sea bridges are characterized by large construction investment, long design service period, poor working environment and high seismic risk. In recent years, with the increasing demand and investment in infrastructure construction in China, the construction of cross-sea bridge projects is also increasingly prosperous. As the most important force component, it is very important to maintain the safe and reliable performance of bridge pier in the whole service life of bridge across the sea. The historical seismic data and the research of scholars at home and abroad show that the bridge piers across the sea may be subjected to severe chloride corrosion and multiple earthquakes in the course of service. In this paper, the following aspects of the research work are mainly carried out: (1) based on historical seismic statistics, The seismic hazard analysis model and statistical principles are used to discuss the probability of the occurrence of multiple earthquakes in different forms during the service period of the structure. The results show that the probability of the structure being subjected to two or more completely unrelated earthquakes or earthquake sequences during its life cycle is extremely low. But the probability that it will encounter an earthquake sequence that contains more than one earthquake motion is very high. Therefore, it is necessary to study the action of this kind of earthquake sequence. (2) based on the structural method of earthquake sequence proposed by foreign scholars, by introducing 10 sets of actual aftershock records of the same station records from the peer strong earthquake database, the authors have obtained the following results: 1. The sequence of ground motion that is more consistent with the real situation; In nonlinear dynamic time-history analysis, a series of ground motion sequences are continuously input into the pier model in order to consider the cumulative damage caused by multiple earthquakes. (3) the chloride ions, which have the greatest influence on the durability of bridge piers across the sea, are discussed. Corrosion behavior and corrosion of steel bars in high performance concrete used in marine environment were analyzed based on Life-365 software. The results show that despite the use of protective measures such as high performance concrete and rust inhibitor, it is still difficult to avoid chloride corrosion in the course of its service for a hundred years. It leads to the corrosion of steel bar and then affects the seismic performance of pier. (4) based on incremental dynamic analysis and seismic vulnerability analysis method, the bridge pier is not corroded in the process of service. In the 60th, 80th and 100th year of service of the corroded bridge pier, the responses of the pier under the action of single main shock and earthquake sequence are analyzed and the difference of the response of the pier under the action of single main shock and earthquake sequence is also compared. The analysis results show that the piers are basically in linear working condition in the condition of slight failure, and are not affected by the effect of service time and earthquake sequence, while in the condition of moderate, severe and complete failure, the bridge pier is in a linear working state, and the bridge pier is not affected by the effect of service time and earthquake sequence. The pier is in a plastic state, and the service time and earthquake sequence have a great influence on the displacement response and vulnerability curve of the pier, and the pier is easier to enter the dangerous state.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U443.22

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