3×340m公铁同层合建多塔斜拉桥总体设计

珠机城际铁路金海特大桥位于磨刀门水道入海口,与金海高速公路大桥同层合建,主桥采用(58.5+116+3×340+116+58.5)m四塔三主跨斜拉桥。桥面宽度达49.6 m,中间布置荷载较重的双线城际列车,两侧布置荷载较轻的高速公路。为提高多塔斜拉桥的结构刚度并释放长联温度效应,采用刚构-连续体系,中塔塔梁墩固结,边塔塔梁固结、塔墩分离。主梁采用大挑臂式钢箱梁结构,由单箱三室钢箱梁加两侧挑臂组成,便于钢箱梁腹板与钢塔的壁板连接,实现塔梁固结。桥塔采用空间四柱式钢塔,其下桥墩为钢筋混凝土双肢薄壁结构。斜拉索采用LPES7-199~LPES7-379型Ⅱ级松弛平行钢丝拉索,按两平行索面扇形布置。钢塔及钢梁在工厂制造,再浮运至桥位安装。结构静动力分析结果表明,结构受力性能良好,安全可靠。

Overall Design of a 3×340m Multi-pylon Cable-Stayed Bridge with Deck Accommodating Both Vehicle and Railway Traffic

The Jinhai Bridge on Zhuhai Urban-Airport Mass Rapid Transit is located at the estuary of the Modaomen Waterway,which merges with the Jinhai Highway Bridge,creating a deck carrying both vehicle and railway traffic.The main bridge is a four-pylon cable-stayed bridge with three main spans and with specific span arrangement of 58.5,116,3×340,116 and 58.5 m.The deck has a width of up to 49.6 m,with two heavy transit lines arranged in the central zone and relatively lighter highway lanes on the two sides.To improve the structural rigidity of the multi-pylon cable-stayed bridge and release the temperature effect in long continuous unit,a rigid-framed and continuous system is adopted.The two intermediate pylons,the girder and the piers are fixed,but the two side pylons are only fixed with girder,and the pylons and the piers are separated.The main girder is a steel box girder structure with long cantilevers,consisting of the three-cell single box steel box girder and the cantilevers on the two sides,to facilitate the connection of the webs of the steel box girder and the walls of the steel pylons so as to realize the fixation of the pylons and the girder.The pylons are the spatial steel pylons each having four columns,and the pylon piers are the reinforced concrete thin-walled structures each with two legs.The stay cables are formed of the GradeⅡparallel low relaxation steel wires of LPES7-199~LPES7-379 type,arranged in fan formation in two parallel cable planes.The steel pylons and the steel girder are fabricated in the factory and floated to the bridge site for installation.The results of the static and dynamic analysis show that the load bearing performance of the bridge is good and the structure is safe and reliable.