混凝土结构耐久性设计原则、方法与标准

结合最新颁布的《混凝土结构耐久性设计标准》(GB/T 50476—2019)综述混凝土结构耐久性的总体设计原则、方法和规定。结合混凝土结构耐久性的定义，分析耐久性设计的三要素：性能劣化、耐久性极限状态以及设计使用年限，强调耐久性设计需要向全寿命耐久性规划拓展。结合标准规定，解析使用环境分类和等级划分表示性能劣化、耐久性极限状态以及设计使用年限针对整体结构与构件的不同含义。然后，结合定性设计方法分析典型环境下材料和构件层次上耐久性规定以及耐久性指标，针对防腐蚀附加措施和后张法预应力体系分析耐久性多重保护的理念。综述表明，标准最大程度总结了我国混凝土结构耐久性科学认识与工程实践，发展基于模型的性能化设计、设计阶段系统开展维护设计、推动耐久性多屏障设计理念是耐久性标准将来的发展方向。

Durability design of concrete structures: principle,method and standard

The principle, methods and regulations for durability design of concrete structures are reviewed on the basis of the newly issued Standard for design of concrete structure durability (GB/T 50476—2019). Firstly, by referring to the definition of concrete structural durability, three key concepts of durability design, namely the performance deterioration, durability limit state (DLS) and design service life, are analyzed, and it is emphasized that the durability design shall be extended to life-cycle durability planning. Based on the standard, the environmental classification, DLS for main durability processes and the different definitions of service lives for structure and elements are clarified. Then, the technical requirements of durability are reviewed for typical environments on both material and element levels and the multiple protection is explained through the additional corrosion protection measures and the protection of post-tensioning prestressed system. The review indicates that the standard greatly summarizes the scientific understanding and engineering practice in China, and the model-based performance design, maintenance planning in design phase and durability design through multiple protection shall be the future development.