沿海在役钢筋混凝土桥梁性能退化及剩余使用寿命预测

发布时间：2018-01-11 18:30

本文关键词：沿海在役钢筋混凝土桥梁性能退化及剩余使用寿命预测　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：沿海地区的公路桥梁由于受到氯离子的侵蚀等环境因素使得钢筋锈蚀,进而结构性能劣化、抗力衰减,甚至是倒塌破坏,不得不花费大量资金维修加固甚至是重建,造成巨大的经济损失和严重的社会影响。本文在国家自然基金“在役混凝土箱梁桥时变承载力的分析理论及试验研究”的资助下,结合“台州沿海混凝土桥梁性能退化及灾变机理研究”项目,基于全寿命周期理论,对沿海在役混凝土桥梁的性能劣化机理从耐久性、可靠性展开研究与讨论,预测既有混凝土桥梁的耐久性寿命、承载力寿命,进而确定结构的剩余使用寿命以及桥梁的最佳维护策略等。主要研究工作如下： 1、从耐久性、可靠性以及全寿命周期理念三个方面综述和概括了混凝土结构预测剩余使用寿命的研究进展及预测模型,指出研究现状及存在的不足；统计分析了台州地区340座混凝土桥梁病害发生的部位,重点研究下部结构构件的耐久性和可靠性,从而评估结构的安全性； 2、针对台州沿海混凝土桥梁经受氯离子侵蚀、混凝土碳化以及钢筋锈蚀的劣化特点,在碳化深度的计算模型中引入了水灰比参数,并进行了构件层次上的混凝土碳化和钢筋的锈胀的动态可靠度的分析计算,预测了工程实例的耐久性寿命,为桥梁管养部门提供可靠的依据； 3、提出了基于荷载影响因子和氯离子结合能力的两种因素耦合的氯离子扩散的修正模型,与传统的考虑单一因素的氯离子扩散模型相比,修正的氯离子扩散模型更贴近混凝土桥梁的实际,更加合理；基于此氯离子扩散的修正模型,建立了考虑荷载影响因子和氯离子结合能力的两种因素的钢筋锈蚀模型,并与现有的钢筋锈蚀模型进行了对比,所提出的考虑荷载影响因子和氯离子结合能力的两种因素的钢筋锈蚀模型更加合理,为准确的预测混凝土桥梁的剩余寿命提供理论依据； 4、基于上述氯离子扩散修正模型和钢筋锈蚀模型(材料劣化模型),只考虑钢筋材料对结构抗力衰减的影响,计算分析了背景桥梁各构件的时变可靠度与失效概率,进一步预测了剩余使用寿命； 5、基于系统部件可靠性评估的寿命分布函数,应用于桥梁工程,对结构的各个构件的连接形式(串联、并联以及混联)进行了失效概率的计算分析,给出了寻求基于寿命周期函数的最佳维护策略的步骤,从失效概率和累积成本找出最优的维修加固方案,结合工程实例进行了验证为桥梁管养部门提供理论指导； 6、沿海地区公路桥梁性能的劣化表征为可靠性指标和状态指标的劣化,建立了可靠性指标和状态指标的劣化模型,性能劣化模型中考虑了荷载和环境的影响,并以性能指标劣化模型为基准,建立了全寿命周期内的维护策略的优化模型,利用遗传算法(GA)对优化模型进行了分析计算,综合评价了全寿命周期内的经济效益,给出了数值实例的最优维护策略。
[Abstract]:Based on the theory of full - life cycle theory and the research and discussion on the performance degradation mechanism of coastal active concrete bridge from durability and reliability , this paper predicts the durability and life of existing concrete bridge , and then determines the remaining service life of the structure and the best maintenance strategy of the bridge . The main research work is as follows : 1 . The research progress and prediction model of the remaining useful life of the concrete structure are summarized and summarized from three aspects of durability , reliability and life cycle concept . 2 . According to the characteristics of chloride ion erosion , concrete carbonization and deterioration of reinforcement corrosion , the water - cement ratio parameter is introduced in the calculation model of carbonation depth , and the analysis and calculation of the dynamic reliability of concrete carbonation and rust expansion on the component level are carried out . The durability life of the engineering example is predicted , which provides a reliable basis for the bridge maintenance department ; 3 . A modified model of chloride ion diffusion coupled with two factors based on load factor and chloride ion binding capacity is proposed . Compared with the traditional chloride ion diffusion model considering single factor , the modified chloride ion diffusion model is closer to the practical and more reasonable model of concrete bridge . Based on this model of chloride ion diffusion , the reinforcement corrosion model considering the two factors of load influence factor and chloride ion binding capacity is established , which provides theoretical basis for accurate prediction of residual life of concrete bridge . 4 . Based on the chloride ion diffusion correction model and the reinforcement corrosion model ( material degradation model ) , only the influence of the reinforcement material on the attenuation of the structural resistance is considered , and the time - varying reliability and the failure probability of each component of the background bridge are calculated and analyzed , and the remaining service life is further predicted ; 5 . Based on the life distribution function of the reliability evaluation of the system parts , the failure probability calculation and analysis of the connection form ( series , parallel connection and parallel connection ) of each component of the structure are analyzed , and the optimal maintenance strategy based on the life cycle function is found out , and the optimal maintenance reinforcement scheme is found out from the failure probability and the cumulative cost , and the engineering example is verified as the bridge control department to provide theoretical guidance ; 6 . The deterioration of highway bridge performance in coastal areas is characterized by the deterioration of reliability index and status indicator , the deterioration model of reliability index and state index is established , the optimization model of maintenance strategy in full life cycle is established based on performance index degradation model , and the optimization model is analyzed and calculated by genetic algorithm ( GA ) , and the optimal maintenance strategy of numerical example is given .

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U445.7;U448.34

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