北京铁路枢纽丰台站改建工程112 m六线钢箱叠合拱桥设计

The Design of 112 Meters Steel Box Double-arch Bridge with Six Trucks for Reconstruction Project of Fengtai Railway Station of Beijing Railway Hub

北京铁路枢纽丰台站改建工程高速场跨越北京西四环路采用112 m六线简支钢箱拱桥。为确保六线超宽结构受力合理、线路横向变形协调及施工便捷,首先采用“拱间布置四线、两拱外侧各悬挑一线”的线路布置方案,拱肋采用叠合拱,上、下拱肋间设竖连杆,采用刚性吊杆,纵梁兼做系梁;其次,采用密横梁正交异性不锈钢复合桥面系;再次,在梁端设横向限位和牛腿与邻跨衔接;最后,采用“旁位拼装、先横移、再纵向顶推”的施工方案。研究结果表明:该叠合拱结构具有良好的竖、横向刚度;各构件的受力性能及多线梁端横向位移均满足规范要求;施工方案能够适应复杂的现场环境实现快速化施工。

The reconstruction project of Fengtai Station of Beijing railway hub adopts 112m steel box double-arch bridge with six tracks to cross over Beijing West Forth Ring Road.In order to ensure that the six-line ultra-wide structure is reasonably stressed,the horizontal deformation of the line is coordinated and the construction is convenient,firstly,the line layout plan of“arrangement of four lines between arches and overhanging one line on the outside of two arches”is adopted,the arch rib of double-arch is employed,vertical connecting rods are arranged between the upper and lower arch ribs,rigid suspenders are used,and the longitudinal beams serve also as tie beams.Secondly,dense crossbeam orthotropic stainless steel composite deck system is used.Thirdly,a lateral limit device is installed at the middle of the end beam and the neighboring spans are linked with corbels.Finally,the construction scheme of“side-by-side assembly,horizontal movement and then incremental launching construction along the line axis”is followed.The research results show that the double-arch structure has good vertical and lateral stiffness;the mechanical performance of each member and the lateral displacement of the multi-line beam end meet the specifications;the construction scheme can adapt to the complex site environment for rapid construction.