上海长江大桥结构防腐蚀技术措施

Technical Measures for Corrosion Protection of Shanghai Changjiang River Bridge Structure

根据上海长江大桥桥位处长江入海口的环境条件、桥梁结构特点以及不同构件所处的暴露环境区段的特殊性,进行结构防腐蚀设计,提出满足设计使用年限100年的技术措施。混凝土结构采用高性能混凝土与适当的混凝土保护层厚度及涂层等保护措施;钢管桩采用熔融结合环氧粉末涂层与外加电流阴极保护的联合保护;钢主梁外表面采用电弧喷铝长效防腐技术,钢主梁内部采用除湿系统,控制室内空气相对湿度在50%以下。对高性能混凝土从原材料、配合比、拌制、浇筑、养生等施工环节制定了相应的质量控制措施。

In accordance with the environmental conditions of the estuary of the Changjiang River at the bridge side of Shanghai Changjiang River Bridge, the characteristics of the Bridge structure and the peculiarity of the components of the Bridge that are exposed in the different environmental sections, the corrosion protection for the structure was designed and the technical measures that could satisfy the 100-year designed service life were put forward. For the part of the concrete structure of the Bridge, the protection measures like the high performance concrete, appropriate concrete cover thickness and coating were taken. For the steel pipe piles, the joint protection system of the fused epoxy powder coating plus the impressed current cathodic protection was used while for the steel box girders, the exterior surfaces of the girders were protected by the long-term protection technique of electric arc sprayed aluminum and the interior surfaces were protected by the dehumidification system with the relative humidity of the air in the control chamber being below 50%. For the high performance concrete, the corresponding quality control measures were also formulated from aspect of the raw materials, mix proportioning and various construction steps of mixing, casting and curing.