变截面预应力混凝土现浇箱梁在跨线桥梁中的应用

Application of Variable Cross-section Pre-stressed Concrete Cast-in-situ Box Girder Bridge in Overpass Bridge

以综合保税区内跨线桥梁为例,阐述了变截面预应力混凝土现浇箱梁在跨线桥梁中的应用。首先根据桥址处被交路的现状及规划情况,跨桥桥梁就现浇箱梁和钢箱梁的方案进行了比选,从结构型式、施工难易程度、对被交路交通的影响程度、运营期养护情况、施工工期及综合建安费比等几个方面比较了两个方案的优劣,选用变截面预应力混凝土现浇箱梁为推荐方案;然后从构造设计、结构计算、施工要点三个方面对现浇箱梁设计进行了全面的分析,现浇梁方案设计合理,满足规范设计要求。结果表明桥梁上部结构应尽量选用耐久性较好的预应力混凝土结构,很好地展示了变截面预应力混凝土现浇箱梁在跨线桥梁中的应用与发展前景,对同类跨线桥的设计有一定的借鉴作用。

Taking an overpass bridge in the comprehensive bonded zone as an example, this paper sets forth the application of variable cross-section pre-stressed concrete cast-in-situ box girder in the overpass bridge.Firstly based on the present and planning situations of crossroads at the bridge site, this paper compares and selects the schemes of cast-in-situ girder and steel box girder of overpass bridges. After the analysis on the advantages and disadvantages of two schemes from the structural style, construction difficulties, traffic impact of crossroad, maintenance during operation, construction period and engineering cost and so on, the variable cross-section pre-stressed concrete cast-in-situ box girder is selected as the recommended scheme.Then, this paper completely analyzes the design of cast-in-situ box girder from three aspects of structure design, structure calculation and construction essentials. The scheme design of cast-in-situ girder is reasonable and meets the design standards and requirements. The result shows that the superstructure of bridge should be the pre-stressed concrete structure with the good durability as far as possible, and shows the application and development prospect of variable cross-section pre-stressed concrete cast-in-situ box girder in the overpass bridge, which can be referred for the design of the similar bridges.