永临结合的墩顶转体法在铁路连续梁桥施工中的应用研究

与常规的墩底转体法相比,墩顶转体法减轻转体质量,降低球铰制造、运输及安装的难度和转体重心高度,减小承台尺寸,缩短基坑敞口时间,提高跨线施工的安全性,是铁路连续梁桥转体施工新的发展方向;结合转体系统布置于墩顶的特点,对支撑体系进行优化,并采用钢管混凝土转台,减少转体机构尺寸,同时增加施工操作空间;在转台设计中引入夹层钢板,通过抽取夹层钢板,将转体球铰转换为防落梁挡块,实现转体施工结构设计的永临结合;提出桥梁墩顶转体、永久支座安装、结构体系转换等全套的施工工艺,可供后续工程参考。永临结合的墩顶转体法施工铁路连续梁,丰富了我国转体桥梁的设计和建造技术,取得了较好的经济效益和社会效应,应用前景广阔。

Application of Pier Top Rotation Method with Combination of Permanent and Temporary Facilities in Railway Continuous Beam Construction

Compared with the conventional pier bottom rotation method,the pier top rotation method is a new and leading development in the rotate construction of railway continuous beam bridges. It reduces rotation weight,minimizes difficulties and cost in the manufacture,transportation and installation of the spherical hinge. It also reduces the size of pile cap,lowers the center of gravity and improves the safety of cross railway construction. According to the structural characteristics of railway continuous beam,this paper studies pier top rotation technique,solves the problems of high bearing capacity and limited size of the turntable by using concrete-filled steel tubular structure,determines the adaptive rotation system,girder and pier structure,puts forward a complete set of construction technology and provides reference for the design of swivel continuous beam bridge. Pier top rotation technique enriches the design and construction of the swivel bridge in China,achieves good economic and social benefits with broad application prospect.