太阳河大桥结构耐久性设计

摘要

The Taiyanghe River Bridge are composed of a suspended cable-arch structure and a rigid-frame structure with oblique legs ,the former belongs to an elastically supported continuous girder with multiple supports and the latter is a rigid-frame system with V-shaped piers .The main girder is a prestressed concrete structure and the arch ribs are steel and concrete hybrid structures . Because the bridge is exposed in the marine environment ,its structural durability should be given top priority .Based on the existing durability design codes and other documents ,to increase the thickness of the concrete cover and the compactness of concrete are regarded as the fundamental measures in the concrete durability design .The load bearing capacity of the structure was opti-mized and the maintenance condition for the components was improved so as to reduce the impact of minor cracks on the durability of components .Mcreover ,a series of auxiliary measures ,such as using rust inhibitor ,concrete coatings and permeable formwork lining were taken as well .The steel structure is protected using the corrosion prevention technique ,and selectively using the heavy corrosion protection coatings and the thermal spraying composite coatings .Meanwhile ,to further ensure the durability of the structure ,specific requirements for construction technique and construction quality control of the bridge are proposed .%太阳河大桥由拱索支撑结构和斜腿刚构组成，其中拱索支撑结构为多支点弹性支撑连续梁，斜腿刚构部分为V形墩刚构体系，主梁为预应力混凝土结构，主拱为钢-混凝土混合结构。该桥位于近海环境，其结构耐久性问题突出，在现有的耐久性设计规范和其它文献资料的基础上，采取增加混凝土保护层厚度和密实性作为混凝土耐久性设计的根本措施，通过优化结构受力和改善构件养护条件来减小裂缝对构件耐久性的影响，并采取了阻锈剂、混凝土表面涂层和透水模板衬里等辅助措施；钢结构采用防腐涂装技术，并且有选择性地采用了重防护涂料和热喷涂复合涂层防腐技术。同时，为了进一步保障结构的耐久性，对桥梁的施工工艺和施工质量控制提出了具体要求。