沪通长江大桥主航道桥主梁结构设计

Structural Design of Main Girder of Main Ship Channel Bridge of Hutong Changjiang River Bridge

沪通长江大桥主航道桥为(140+462+1 092+462+140)m的公铁两用双塔斜拉桥,采用公路在上、铁路在下的双层桥面布置,主梁为三片主桁钢桁梁结构。主梁上弦公路桥面采用正交异性整体钢桥面板(两侧边跨252m范围公路桥面采用纵横梁结合混凝土桥面的结构形式),下弦铁路桥面由与主梁断面同宽的钢箱组成,上、下弦桥面与主桁结合参与整体受力。主桁采用N形桁式,上、下弦杆件均采用板肋加劲箱形截面,腹杆采用箱形或H形截面,主桁节点为全焊接整体节点。在全桥主桁节点处均设有横联。采用桥梁空间分析软件3D-bridge开展结构整体计算并采用ANSYS进行节点应力分析,结果表明结构设计满足规范要求。

The main ship channel bridge of the Hutong Changjiang River Bridge is a rail-cumroad double-pylon cable-stayed bridge with span arrangement（140＋462＋1 092＋462＋140）m.The bridge is arranged into the double decks,of which the upper deck carries the highways while the lower deck carries the railways.The main girder of the bridge is the steel truss girder structure made up of three main trusses.The highway deck on the upper chords of the main girder is the integral orthotropic plate steel deck（in the 252 mranges of the side spans on both sides,the highway deck is the structure composited by the stringers,cross beams and concrete deck slabs）.The railway deck on the lower chords is formed by the steel box that has the same width with the cross section of the main girder.The decks on the upper and lower chords are all composited with the main trusses and contribute to the loading bearing of the whole structure of the main girder.The main trusses are the N-shape trusses,the members of the upper and lower chords are the box sections stiffened by the plate ribs and the web members are the box or H shape sections.The panel points of the main trusses are the all-welded integral panel points and at the panel points of the main trusses of the whole bridge,the lateral bracing systems are arranged.The whole structure is calculated,using the spatial analysis software 3D-bridge and the stress of the panel points is analyzed,using the software ANSYS.The results of the calculation and analysis demonstrate that the structural design of the main girder can satisfy the relevant requirements in the codes.