钢筋混凝土结构基于锈胀开裂寿命准则的耐久性设计方法

Durability design of RC structures based on the life criterion of cover cracking

在混凝土结构耐久性的研究中,锈胀开裂寿命是以混凝土表面出现顺筋的锈胀裂缝所需时间作为结构的使用寿命.根据理论与经验相结合的描述碳化与锈蚀发展的数学模型,选择混凝土保护层厚度与混凝土立方体抗压强度作为耐久性设计参数,建立了基于锈胀开裂寿命准则的耐久性概率极限状态设计方法,给出了该极限状态的目标可靠指标、设计表达式与分项系数.设计时将混凝土保护层厚度与混凝土立方体抗压强度的均值与对应的分项系数代入设计表达式验算满足后,即可在一定可靠度水准上得到耐久性设计参数的取值,通过算例说明了设计过程.

In the research of durability of concrete structures, the service life of concrete structures terminated in appearance of cover cracking caused by reinforcement corrosion is the so-called cracking life. According to the theoretical ＆ empirical combined deterioration models with respect to the processes of concrete carbonation and reinforcement corrosion, the protective cover thickness and cubic compressive strength of concrete are considered as the durability parameters. The design method of probability limit states based on the cracking criterion is established, and the acceptance criteria, partial factors, and design expressions for the cracking limit state are provided. Through the design expressions, the cover thickness and compressive strength of concrete can be determined directly under a certain reliability level. Finally, the design process is illustrated by an example.