上莘大桥结构设计与分析

Structural Design and Analysis of Shangshen Bridge

上莘大桥为半穿式连续钢桁架桥,跨径布置为(62+100+62)m。综述了该桥的桥型方案、结构总体设计及设计要点。该桥上部结构由桥面板、桥面系、主桁、联结系和支座5部分组成。桥面板为组合结构,桥面铺装采用树脂沥青组合体系;桥面系由主横梁、次横梁、次纵梁构成;主桁采用无竖杆的华伦式三角形腹杆体系及整体节点。下部结构采用柱式桥墩,肋式桥台,基础为钻孔灌注桩。由于结构受力时桁架节点与杆件的连接介于完全刚接与铰接之间,为使结构更安全合理,设计时节点刚度及杆件跨中应力按铰接模型计算,杆端应力按刚接模型计算,以铰接模型的轴应力+刚接模型的弯曲应力作为设计控制应力。

The Shangshen Bridge is a half-through continuous steel truss bridge with span arrangement（62＋100＋62） m.A summarized account of the bridge type options,structural overall design and design key points of the bridge is presented.The superstructure of the bridge is composed of 5 parts of the deck plate,floor system,main truss,bracing systems and bearings.The deck is a composite structure and is surfaced with resin asphalt composite system.The floor system is made up of the main cross beams,secondary cross beams and secondary stringers while the main truss is designed as a Warren truss system without vertical members and with integral panel points.The substructure of the bridge is of the column piers and ribbed abutments,the foundations of which are the bored piles.Because the connection of the panel points with the members of the truss under loading is in between the complete rigidity and hinge and in order to keep the structure still safer and more rational,in the design of the bridge,the rigidity of the panel points and the midspan stress of the members are calculated in accordance with the hinge model,the end stress of the members is calculated in accordance with rigid connection model and the axial stress of the hinge model and the bending stress of the rigid connection model are taken as the stress that will govern the design.