悬索桥板桁结合加劲梁钢-STC组合桥面支承体系设计优化

Design Optimization for Steel-STC Composite Deck Supporting System in Deck-Truss Composite Stiffening Girder of Suspension Bridge

杭瑞高速岳阳洞庭湖大桥为(1 480+453.6)m双塔双跨钢桁梁悬索桥,主梁为采用了钢-STC轻型组合桥面的板桁结合型钢桁加劲梁,钢-STC轻型组合桥面支承体系由横向桁架支承及桥面纵、横梁支承组成。采用ANSYS软件建立主梁节段有限元模型,针对组合桥面支承体系,从横向桁架结构形式、桥面纵横梁体系及其结构尺寸等方面进行设计优化。结果表明,带竖腹杆的横向桁架结构形式在桥面刚度、构件应力水平方面均具有较大优势;多横梁体系桥面刚度大,桥面构件应力水平低,适用于钢-STC轻型组合桥面。洞庭湖大桥板桁结合加劲梁钢-STC组合桥面支承体系采用带竖腹杆的横向桁架,纵横梁支承体系采用在横向桁架竖腹杆位置设置边纵梁、次横梁间距2.8m的多横梁体系,能够很好地兼顾结构刚度、应力水平及钢材用量。

The Dongting Lake Bridge on Hangzhou-Ruili Expressway in Yueyang is a two-tower two-span steel truss girder suspension bridge with spans of 1 480 m and 453.6 m.The main girder adopts the deck-truss composite stiffening girder with light steel-STC composite deck(“STC” refers to super toughness concrete.).The light steel-STC composite deck supporting system consists of the transverse trusses,stringers and cross beams.The ANSYS software was used to establish the finite element model of the main girder sections.For the composite deck supporting system,the design optimization contained the optimization of transverse truss structure,the deck stringers and cross beams system and structure dimensions.The results demonstrate that the transverse truss structure with vertical web members is superior in terms of deck stiffness and stresses in the components.The deck system with multiple cross beams has great stiffness,the stresses in the deck components are low,which is applicable to the light steel-STC composite deck.In the Dongting Lake Bridge,the deck-truss composite stiffening girder adopts the steel-STC composite deck supporting system that consists of transverse truss with vertical web members and the stringers and cross beams supporting system.In the stringers and cross beams supporting system,edge stringers are installed at the locations of the vertical web members of the transverse truss,and the intervals between subsidiary cross beams are 2.8 m.This type of stiffening girder better balances the structural stiffness as well as stresses in components and the steel used.