摘要
系统阐述港珠澳大桥跨海工程混凝土结构耐久性设计的原则与方法,首先介绍港珠澳大桥工程概况及120年使用年限的总体要求;根据工程的环境、水文地质数据分析工程场址条件下混凝土结构劣化的主要过程和因素;确定耐久性设计的控制过程为海洋氯离子侵入和表层混凝土碳化引起的钢筋锈蚀。针对耐久性控制过程,分析耐久性极限状态、构件使用年限、环境作用类别和程度以及裂缝控制宽度;然后建立针对港珠澳大桥工程场址条件的氯离子侵入过程设计模型,使用全概率方法校准的分项系数法完成针对不同时用年限、不同暴露条件下的结构耐久性参数和混凝土保护层厚度设计;最终确定用于港珠澳大桥混凝土结构120年使用年限的耐久性设计与质量参数。
The principles and procedure for the durability design of concrete structures in Hong Kong-Zhuhai-Macao( HZM) project for a design working life of 120 years are introduced. The environmental actions are firstly analyzed and classified for the project,and the possible deterioration processes for structural concrete are identified with respect to their mechanisms. The durability design is conducted from both materials composition control and performance-based design. The target design service life and durability limit states are attributed to concrete elements according to their structural importance and maintenanceability. According to the prescriptive requirements on material compositions,the carbonation-induced and chloride-induced corrosions of reinforcement steel are considered as most critical processes that control the design. The thickness and quality of concrete covers are determined from chloride penetration model using a partial factor design scheme. For chloride ingress,the partial factors are calibrated from full probabilistic approach for a target reliability β = 1. 3. The statistical properties of parameters are regressed from 30-year exposure test data. Finally,the relation between the design values of chloride diffusion coefficient and the laboratory measured values is analyzed to establish a basis for durability quality control in construction.
出处
《土木工程学报》
EI
CSCD
北大核心
2014年第6期1-8,共8页
China Civil Engineering Journal
基金
国家科技支撑计划(2011BAG07B04)
