氯盐环境下钢筋混凝土结构全寿命时变性能及性能可靠度研究

The life-cycle performance of structure has close relations with its safety,applicability,economy,and other requirements.In order to develop design theory of life-cycle,this subject will conduct basic science research on the time-varying performance of concrete structure and its reliability methods,and the study is done under wide existing chloride environment in our country,and taking the structure performance as research object from the point of view of life-cycle design.Firstly,based on seeking quantified new indexes of controlling structure performance design,combining with the current structure design indexes,the performance index system of structure life-cycle performance design will be constructed; And then,the relationship between flexural bearing capacity,corrosive bulge crack width of structure and steel corrosion rate,and the relationship between steel corrosion rate and time will be established on the basis of research on influencing factors of material performance,structure performance of steel and concrete,degradation mechanism,degradation time-varying process,and etc,and subsequently a time-varying model of flexural bearing capacity and corrosive bulge crack width of structure will be set up.And conformity test on time-varying model will also be verified.Finally,an analysis approach on time-varying reliability of structure performance will be set up according to the research on the statistical characteristic and probability distribution of its influencing factors.This subject aims at making breakthrough and innovation on the design theory.

结构全寿命性能关系到结构的安全、适用、经济等要求。为了发展全寿命设计理论，本课题以我国广泛存在的氯盐环境为背景，以结构性能为研究对象，从全寿命设计的角度，对混凝土结构时变性能及性能可靠度方法进行基础科学研究。首先寻求能量化控制结构性能设计的新指标，结合原有结构设计指标，构建结构全寿命性能设计的性能指标体系；然后基于对钢筋和混凝土材料性能、结构性能的影响因素、劣化机理、劣化时变过程等研究，建立起结构抗弯性能及锈胀裂缝宽度性能随钢筋锈蚀率的关系，混凝土内钢筋锈蚀率随时间变化的关系，进而建立结构抗弯性能及锈胀裂缝宽度性能的时变模型。并对时变模型进行符合性试验验证。最后通过对结构性能影响因素的统计特征和概率分布研究，建立起结构性能时变可靠度分析方法。本项目旨在设计理论与方法上有所突破和创新。

混凝土结构在腐蚀环境中的性能劣化关系到结构的安全、适用、经济等要求。本项目以我国广泛存在的氯盐环境为背景，以结构性能为研究对象，从全寿命设计的角度，提出了控制结构耐久性的设计指标。结合现有结构设计指标，构建了混凝土结构全寿命性能设计的性能指标体系；从性能指标体系中选择对结构安全性及适用性影响最大的抗弯性能及锈胀裂缝宽度性能指标，从其影响因素、劣化机理、时变规律等方面进行深入研究，建立了混凝土结构全寿命抗弯性能及锈胀裂缝宽度性能的时变模型。运用该时变模型，可以预测不同使用年限时结构抗弯承载力的退化程度及锈胀裂缝宽度的开展情况，为优化结构耐久性设计参数、确定结构的使用寿命及制定结构维护维修加固等策略提供了科学依据。针对结构的安全性能，基于抗力劣化的时变模型，建立了结构全寿命性能动态可靠度分析方法。在现有结构可靠度理论的基础上，创新性地引入结构耐久性系数来考虑抗力衰减对可靠指标的影响，并将劣化结构的可靠度设计方法转化为分项系数的设计表达形式，同时给出了耐久性系数的确定方法。.本项目建立的结构全寿命性能设计指标体系、抗弯承载力及锈胀裂缝宽度时变模型、考虑抗力衰减的可靠度分项系数设计方法，对促进结构全寿命设计理论的发展具有十分重要的理论意义。