Durability design method of concrete structures

For the main problems existing in durability design of concrete structures, a durability design method, i.e., durability factor method is proposed. Based on the proposed method, durability optimum design is discussed from three levels. materials, members and structure system. For concrete materials, the general efficacy coefficients including chloride iron permeation coefficient, concrete compressive strength and workability were taken. The minimum average yearly investment was used to optimize durability design for members level with a full consideration of constrain conditions including carrying capacity of sections, deformation, the maximum crack width, construction requirement, and so on. And force-pass-tree-based durability contribution coefficient was considered as optimum design for concrete structures. The presented method, which emphasizes the importance of concrete structure system, level design, couple action of infected durability factors such as environment, load and service life cycle cost analysis for durability design, has the advantages of explicit concept and simple form.