【作者】 孙晓珍；

【导师】 邵旭东；

【作者基本信息】 湖南大学 ， 桥梁与隧道工程， 2007， 硕士

【摘要】 近年来,随着交通事业的迅速发展,越来越多的跨海大桥在建或已建成通车,而钢筋混凝土结构的耐久性失效己逐渐成为困扰土建工程界的一个世界性问题,尤其是处于海洋或恶劣环境下,混凝土结构耐久性的问题更加突出。跨海大桥工程不仅耗资巨大,而且关系着国计民生,如果因为耐久性不足而成为“短命工程”,将对国家造成不可估量的损失。本文按照现场检测→耐久性分析→耐久性评估→剩余使用寿命预测耐久性优化设计的思路对跨海大桥混凝土构件耐久性进行了研究,研究的主要内容如下:(1)介绍了跨海大桥混凝土结构耐久性研究的重要意义、研究内容以及国内外研究现状。(2)在前人研究的基础上归纳总结了氯离子侵蚀作用下钢筋的锈蚀机理,对海洋环境下钢筋锈蚀的主要影响因素进行了分析,尤其对氯离子的侵蚀机理和渗透模型进行了重点研究,总结了海洋环境下钢筋锈蚀模型,并阐述了锈后钢筋的力学性能及其对承载力的影响,结合已有的钢筋防锈措施提出了海洋环境下混凝土结构钢筋防锈措施。(3)根据一般大气环境下混凝土结构耐久性评估准则提出了海洋环境下混凝土结构耐久性评估准则,重点研究了蒙特卡罗方法在可靠度分析中的应用,提出了应用蒙特卡罗方法计算钢筋混凝土偏心受压短柱和钢筋混凝土受弯构件的抗力统计参数,进而较好的解决可靠度分析问题。考虑氯离子的渗透随机过程,修正了海洋环境下钢筋混凝土偏心受压构件和受弯构件的抗力随机模型,用可靠度方法对锈蚀钢筋混凝土偏心受压构件和受弯构件分别进行耐久性分析,重点分析了其各自的可靠度影响因素。(4)以广西铁山港跨海大桥作为背景工程,通过大量现场检测数据,分析了影响该桥结构耐久性的主要因素,对该桥的桥墩和30m主梁分别进行了基于可靠度的耐久性评定,并回归出时变可靠度模型,为同类型桥梁的耐久性评估提供了一定的理论依据。(5)根据结构极限承载能力和耐久性的要求,利用改进的粒子群优化算法对铁山港跨海大桥桥墩截面进行了多变量优化设计。更多还原

【Abstract】 In recent years, more and more bridges across the sea are building or have been built with the development of the traffic, while the problem of the reinforced concrete structure’s invalidation of the durability has become an international problem and puzzles the engineers. Especially in the marine or adverse environment, the problem will be more prominent. The bridges across the sea cost much and affect the national economy and the people’s standard of living greatly. So the "the short-lived project " due to the lack of the durability will bring about an immeasurable loss to the country. This thesis discusses the durability of the reinforced concrete structure of the bridges across the sea from scene detecting, the evaluation and analysis of the durability, the surplus life time forecast to the optimization design. The main work is described as follows:(1) This thesis introduces the important significance, contents and research present situation at home and abroad of the bridges across the sea.(2) Based on the former research, this thesis discusses the rustiness theory of the reinforced bar due to chlorine ion’s corrosion afresh and discusses the main influencing factor of the reinforced bar’s rustiness in the marine environment. The rustiness theory and the infiltration model are discussed especially. A rustiness model in the marine environment is established and the effect on the reinforced bar’mechanics capability and carrying capacity is described. Some related method to deal with the rustiness in the marine environment is proposed based on the existing method.(3) The evaluation rules of the reinforced concrete structure in the marine environment are proposed according to the rules in the ecumenical environment. This thesis discusses the Monte Carlo’s application in the reliability’s analysis, proposes the method calculating the resistance’s factors of the RC eccentrically loaded short column and reinforced concrete bending member by the Monte Carlo so that the analysis problem of reliability can be settled well. The random resistance’s model of the reinforced concrete eccentrically loaded short column and reinforced concrete bending member in the marine environment is established to analyse the structures’durability in which the analysis by the method of reliability of respective influencing factor is the emphases.(4) This thesis adopts the Tieshangang Bridge in Guangxi province as the project background, analyses the main factors affecting the durability of the bridge according to the scene detecting data, evaluates the durability of its piers and 30m-span girder based on the reliability, educes the time-dependent reliability and proposes some theory for the durability’s evaluation of the congener bridges.更多还原