钢筋锈蚀环境下混凝土结构全寿命周期设计与优化初探

发布时间：2018-03-13 19:21

本文选题：混凝土　切入点：氯盐侵蚀　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着跨海桥梁、海洋资源开采平台等严酷服役环境中混凝土结构得到越来越广泛的运用,混凝土结构的耐久性问题也已经变得日益突出。这些混凝土项目结构的耐久性问题给世界各国都带来了沉重的经济负担。因此,利用全寿命周期成本分析(Life-Cycle Cost Analysis,LCCA)理论合理设计与优化严酷服役环境中的混凝土项目结构已经成为当前土木工程领域的研究热点。本课题研究内容来自于国家自然科学基金项目“基于钢筋锈蚀耐久性的混凝土结构全寿命性能及设计理论研究(51378241)”,主要探讨了自然侵蚀环境中钢筋混凝土结构的性能劣化过程,并根据结构时变可靠度探寻了项目全寿命周期成本的评价方法,重点探讨了基于运营阶段的活动成本的结构设计方法。本研究的主要工作如下:1、探讨了混凝土内钢筋的锈蚀反应及其引起的结构性能劣化过程。从钢筋的初始锈蚀到混凝土锈胀裂缝的生成与发展,本文探讨了自然侵蚀环境中混凝土内钢筋锈蚀的发展过程,提出了以钢筋发生初始锈蚀、钢筋发生适量锈蚀等临界条件为极限状态的混凝土结构构件耐久寿命分析方法,反映了钢筋锈蚀对混凝土结构适用性能的影响。同时通过长期氯盐侵蚀环境干湿循环试验获得的锈蚀钢筋试样,探讨了该试验环境下钢筋的不均匀锈蚀形态与力学性能劣化情况,表明了钢筋锈蚀对混凝土结构承载能力的影响。以上研究结果充分说明了利用全寿命周期理论进行钢筋锈蚀环境下混凝土结构设计与优化的现实意义与研究价值。2、建立了混凝土结构全寿命周期成本分析模型与设计理论框架。参考国际标准(ISO2394,1998)给出的优化策略作为目标函数,初步探讨了项目结构全寿命周期成本最小的优化方法。利用概率分析理论方法建立了包括项目结构的初始成本、日常养护成本、服役期内运营活动成本、失效成本和剩余价值等成本项在内的全寿命周期成本分析预测模型。并在此基础上初步探讨了混凝土结构耐久性设计的优化方法,提出了使结构全寿命周期成本趋向最小的参数选取思路,为后续优化钢筋混凝土结构全寿命设计的研究工作提供参考。3、氯盐侵蚀环境中混凝土结构全寿命周期时变可靠度计算分析。为了预测氯盐侵蚀环境中混凝土结构的全寿命周期劣化过程,本研究将其全寿命周期划分为氯离子运输阶段和纵向锈胀裂缝发展阶段。基于现有的混凝土中氯离子运输模型和钢筋锈蚀引起的纵向锈胀裂缝宽度预测模型,本文利用Monte-Carlo抽样模拟法得到了不同设计条件下的混凝土结构时变失效概率与可靠指标曲线,并拟合得到了相应的计算模型。通过比较不同设计条件下混凝土时变劣化曲线,本文初步探讨了如何优化钢筋锈蚀环境下混凝土结构全寿命周期设计。4、初探了氯盐侵蚀环境中混凝土结构全寿命周期设计方法。根据前文得到的不同设计条件下时变可靠度曲线,探讨了不同运营阶段维护与加固活动对项目结构可靠指标的影响,并且建立了不同的运营阶段维护与加固活动布置方案下的运营阶段成本计算评估方法。随后以实际海洋环境中混凝土结构为例计算了相应的运营阶段成本,通过对运营成本计算结果的比较分析,初步探寻了钢筋锈蚀条件下混凝土结构的全寿命周期成本优化的理论方法。最后,以混凝土绿色性能为优化目的改进混凝土配合比的设计方法。
[Abstract]:With the cross sea bridge, marine resources exploitation platform and other harsh service environment in concrete structure has been used more and more widely, the durability of the concrete structure has become increasingly prominent. The problem of durability concrete project structure for all countries in the world have brought a heavy economic burden. Therefore, the analysis of life cycle cost (Life-Cycle Cost Analysis, LCCA) and optimization of concrete structure project harsh environment has become a hot research topic in the field of civil engineering design theory. The research content of the thesis comes from the National Natural Science Foundation Project "Research on performance and design theory of reinforced concrete structure corrosion durability based on whole life (51378241)", mainly discusses the deterioration process of the reinforced concrete structure of natural erosion in the environment, and to explore the reliability of the whole project according to the structure The evaluation method of life cycle cost, discusses the structure design method of the operational phase of the activity based cost. The main work of this research are as follows: 1, discusses the corrosion reaction in concrete and its structural performance deterioration caused by the process. From the initial to the formation and development of corroded reinforced concrete crack. This paper discusses the development process of reinforcement corrosion in concrete erosion of natural environment, put forward to the reinforced concrete structure component for initial corrosion, durability limit state analysis method of critical conditions of moderate corrosion of reinforced, reflects the influence of reinforcement corrosion on concrete structure performance. At the same time through long-term Chloride Erosion corrosion test specimens for the dry wet cycling experiment, discusses the reinforcement of the test environment, uniform corrosion morphology and mechanical properties of the deterioration of the situation, show the rust Effect of corrosion on the bearing capacity of the concrete structure. The above results fully illustrate the practical significance and research value of.2 using the theory of whole life cycle design and optimization of concrete structure corrosion environment, establish the concrete structure of the life cycle cost analysis model and design theory frame. According to international standards (ISO23941998) optimization strategy is given as the objective function, discusses the optimization method of minimum project structure of life cycle cost analysis method. Including the establishment of the initial cost of the project structure by using probability, daily maintenance cost, operation cost of service period, analysis and prediction model of life cycle cost and failure cost and other costs, the surplus value and on the basis of. The preliminary optimization method of durability design of concrete structure is discussed, it is proposed that the structure of life cycle cost trend The idea of choosing the minimum parameters, provide a reference for further research on the optimization of.3 reinforced concrete structure of whole life design, reliability analysis and calculation of concrete structure the whole life cycle of chloride erosion environment. For the whole life cycle deterioration process of concrete structure prediction of Chloride Erosion in the environment, the study of its whole life cycle divided into chloride ion transport phase and longitudinal crack development stage. Prediction model of longitudinal crack width caused by the existing transport model of chloride ions in concrete and steel corrosion based on the Monte-Carlo sampling simulation method has been concrete structure with different design conditions when the failure probability and reliability index curve and fitting the corresponding calculation model. The deterioration curve through concrete comparison of different design conditions, this paper discusses how to optimize the corrosion environment The design of.4 under the whole life cycle of concrete structure, concrete structure life cycle method of chlorine salt erosion in design. According to the reliability curve under different design conditions obtained above, discusses the different operation periods of the maintenance and strengthening of project structure reliability index of the effect, and establish the evaluation method of calculating operation stage the cost of operation of different stages of maintenance and reinforcement arrangement activities under the program. Then the concrete structures in the marine environment in the case of the actual operation stage cost calculated, through the calculation results of the operating costs of the comparative analysis, probes into the theory and method of life cycle cost optimization of the concrete structure corrosion conditions. Finally, optimization objective to improve the concrete mix design method based on green performance concrete.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375

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