市政大跨径简支钢混组合梁桥总体设计

Overall Design of Municipal Long-span Simple-supported Steel-concrete Composite Beam Bridge

针对城市高架桥梁跨越横向道路常用的简支60 m大跨径槽型钢混组合梁桥,对横断面梁片数布置、不同施工方案、降低桥面板收缩徐变措施进行分析.结果表明:(1)少主梁设计相较于多主梁设计经济性更好,但跨中上翼缘板厚会增加较多.(2)设置2个临时支墩,基本可实现钢筋混凝土共同承担一期恒载的效果.(3)与少支架施工相比,整体吊装虽方便施工,但大大提高了钢材的用钢量.(4)无支架施工时,预制桥面板在90 d的存放龄期下,频遇组合可降低混凝土桥面板30%的轴向拉力.

Aiming at the simple-supported 60 m long-span steel-concrete composite beam bridge commonly used for the urban viaduct spanning road,the layout of cross-section beam number,the different construction schemes,and the measures to reduce the shrinkage and creep of deck slab are analyzed.The result shows that the economy of few-girder design is better than that of the multi-girder design.But the thickness of top flange slab in the middle of span will increase much. 2 temporary branch piers are set up, which can basically realize the effect of steel and concrete jointly bearing the first phase of dead load. Compared with the few-support construction, the integral hoisting is easy for construction, but will greatly increase the amount of steel material. The frequent combination can reduce the 30% axial tensile force of prefabricated concrete deck slab at the storing age for 90 d in the construction without support.