火灾后锈蚀混凝土梁残余力学性能研究

Under a marine environment, corrosion in reinforced concrete structures is frequently discovered. Damage assessment and repair of corroded reinforced concrete structures after suffering a fire is an important work. This project will choose corroded concrete beams as the research objects. Mechanical properties of the corroded concrete beams after exposure to fire will be systematically studied from the material to component-level by combination researches of experiments, theoretical analysis and numerical calculation. Firstly, mechanical properties of corroded steel bars considering corrosion rate and temperature will be studied by static tensile tests after suffering different temperatures. Then stress-strain relationship model of corroded steel bars after exposure to high temperatures will be proposed. Influence of temperature, corrosion rate and thickness of protective layer on the bond strength between corroded steel bars and concrete will be studied by eccentric pull out tests. Method for calculating bond strength will be established based on the experimental results and theoretical analysis. Finally, through static load testing researches, theoretical analysis and numerical calculation, degradation behavior of the corroded beams after exposure to fire will be systematically studied. This project will improve the existing fire resistance theory of reinforced concrete structure, and provide the fundamental theory for structural performance assessment and repair after suffering a fire.

海洋环境下混凝土结构往往会发生钢筋锈蚀，火灾后锈蚀混凝土结构的损伤评估与修复加固是一项重要工作。本项目拟以锈蚀混凝土梁为研究对象，从“材料—构件”层次，通过试验研究、理论分析和数值计算相结合的方式对火灾后锈蚀混凝土梁的力学性能进行系统的研究。首先通过对经历不同温度的锈蚀钢筋进行静态拉伸试验，研究锈蚀钢筋力学性能指标与锈蚀率、温度的关系，进而提出高温后锈蚀钢筋的应力-应变关系模型。通过偏心拉拔试验，研究温度、钢筋锈蚀率、保护层厚度等因素对锈蚀钢筋与混凝土粘结性能的影响，基于试验结果和理论分析建立粘结滑移本构模型。最后通过对火灾后锈蚀混凝土梁进行静力加载试验、理论分析和数值计算，研究火灾后锈蚀混凝土梁力学性能退化规律。本项目将完善既有混凝土结构抗火理论，并为火灾后结构性能评定与修复加固提供理论基础。

本项目以“火灾后锈蚀钢筋混凝土梁”为研究对象，从“材料—构件”探索火灾后锈蚀混凝土梁的残余力学性能。首先通过对高温后锈蚀钢筋进行拉伸试验，研究高温后锈蚀钢筋力学性能的退化规律，提出高温后锈蚀钢筋本构模型。然后通过拉拔试验和理论分析，研究高温后锈蚀钢筋与混凝土的粘结性能，提出高温后锈蚀钢筋与混凝土的粘结滑移本构关系。进一步通过火灾后锈蚀混凝土梁静力加载试验研究、理论分析和数值计算，得到火灾后锈蚀混凝土梁残余抗弯性能和抗剪性能变化规律。