氯离子腐蚀环境下RC桥墩抗震性能分析

发布时间：2018-04-16 22:43

本文选题：桥梁 + 氯离子侵蚀　；参考：《湖南大学》2015年硕士论文

【摘要】：随着桥梁结构服役时间的推移,材料的性能会发生退化,尤其是当结构处于氯离子腐蚀环境下时,钢筋和混凝土劣变的程度会更加严重。作为桥梁下部结构的墩柱一旦发生损伤,将影响到整座桥梁的耐久性和安全性,其预定的抗震性能也将会降低,所以有必要对桥墩进行抗震性能分析。本文在“国家自然科学基金(51278183)—基于时变易损性的山区桥梁合理抗震体系研究”的资助下开展,并结合一典型多跨连续梁桥,考虑氯离子腐蚀环境下的RC桥墩发生材料退化,围绕桥墩的抗震性能研究做了以下工作:(1)介绍了桥梁在地震作用下的破坏形式以及面临的耐久性问题,回顾了氯离子侵蚀研究现状和桥梁结构易损性分析的进展,阐明研究钢筋混凝土桥墩抗震性能的必要性。(2)详细讲述了氯离子对钢筋的侵蚀机理,总结了氯离子在混凝土中的扩散模型。基于Fick第二定律,分析了影响氯离子扩散模型的重要因素,并参照规范给出了模型主要参数的取值。(3)采用Open Sees软件建立算例桥梁有限元模型,结合前人研究成果,总结并选择合适的材料退化模型,计算钢筋初始锈蚀时间、锈蚀速率以及钢筋和混凝土的材料退化时变规律。(4)选择三条常用地震波,分别针对氯离子腐蚀环境下的三种分析工况:仅考虑箍筋锈蚀、仅考虑纵筋锈蚀和同时考虑纵筋箍筋锈蚀,对桥墩进行抗震性能分析,比较各工况下抗震能力和地震响应分析结果,并考虑材料退化时效性的影响。(5)基于桥梁地震易损性分析原理,选择合适场地类型的100条地震波,对材料退化前后模型进行非线性时程分析,采用传统可靠度法,对三种工况下桥墩建立时效易损性曲线,比较分析桥墩易损性结果。最后总结了研究的结论,并指出了研究的不足之处以及以后研究发展的方向。
[Abstract]:Along with the service time of bridge structure, the performance of material will degrade, especially when the structure is in chloride corrosion environment, the degree of deterioration of steel bar and concrete will be more serious.Once the pier column is damaged, the durability and safety of the bridge will be affected, and its intended seismic performance will be reduced, so it is necessary to analyze the seismic behavior of the pier.This paper is supported by the National Natural Science Foundation of China 51278183- study on the rational Seismic system of Mountain Bridges based on Time-Varying vulnerability. Combined with a typical multi-span continuous beam bridge, the material degradation of RC pier under chloride corrosion environment is considered.In this paper, the following work is done to study the seismic behavior of bridge piers: 1) the failure forms and durability of bridges under earthquake are introduced, and the research status of chloride ion erosion and the development of vulnerability analysis of bridge structures are reviewed.The necessity of studying seismic behavior of reinforced concrete pier is expounded. The corrosion mechanism of chloride ion to steel bar is described in detail, and the diffusion model of chloride ion in concrete is summarized.Based on the second law of Fick, the important factors influencing chloride diffusion model are analyzed, and the value of the main parameters of the model is given according to the specification. The finite element model of bridge is established by using Open Sees software.Three commonly used seismic waves are selected to sum up and select appropriate material degradation models, calculate the initial corrosion time, corrosion rate and time-varying law of material degradation of steel bar and concrete.According to three analysis conditions under chloride ion corrosion environment: only considering stirrups corrosion, considering only longitudinal reinforcement corrosion and considering longitudinal reinforcement stirrups corrosion at the same time, the aseismic performance of bridge piers is analyzed.Comparing the results of seismic capacity and seismic response analysis under different working conditions, and considering the influence of material degradation time efficiency.) based on the principle of bridge seismic vulnerability analysis, 100 seismic waves of suitable site type are selected.The nonlinear time history analysis of the model before and after the material degradation is carried out, and the time-dependent vulnerability curve of the pier under three working conditions is established by using the traditional reliability method, and the results of the bridge pier vulnerability are compared and analyzed.Finally, the conclusion of the research is summarized, and the deficiency of the research and the direction of the future research are pointed out.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55

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