Durability Design of the Hong Kong–Zhuhai–Macau Sea-Link Project: Principle and Procedure

Abstract

This paper introduces the durability design of concrete structures in the Hong Kong–Zhuhai–Macau project for a working life of 120 years. The environmental actions are analyzed and the deterioration processes for the structural concrete are identified. The durability design is performed through material composition control and a performance-based procedure. The target design lives and durability limit states are attributed to concrete elements according to their structural importance and maintenanceability. Given the prescriptive requirements on material compositions, the carbonation-induced and chloride-induced corrosions of reinforcement steel are considered as the most critical processes and subject to model-based design. The thickness and quality of concrete covers are determined from carbonation and chloride penetration models using a partial factor scheme. For chloride ingress, the partial factors are calibrated from a full probabilistic approach for a target reliability β=1.3. The statistical properties of parameters are regressed from 30-year exposure tests. Finally, the study explores the relation between the design values of the chloride diffusion coefficient and the laboratory-measured values to establish a basis for durability quality control in construction.