超高性能钢管混凝土桥梁结构研究

Study on Structures of Ultra-high-performance Concrete-filled Steel Tubular Bridge

为推动超高性能矩形钢管混凝土组合结构应用并促进桥梁结构轻型化、装配化技术发展,依托沪武高速某跨线桥工程,对中等跨径下承式超高性能钢管混凝土桥梁进行设计研究。提出采用超高性能钢管混凝土组合结构作为桥梁主要承重构件,其高承载力、高耐久性、施工便捷、装配化程度高等优良性能,满足目前对桥梁建设轻型化、薄壁化的发展需求。结合工程建设条件,提出3种主要构件以承受轴向力为主的桥型方案,分别为组合桁梁桥、系杆拱桥以及斜拉板桥,创新性地采用CFRP吊杆、CFRP预应力筋及冷弯卷边U型横梁与UHPC组合桥面板结构,并通过有限元模型对各设计结构进行强度、刚度、稳定性及动力特性分析,得到各验算结果均满足规范要求,并针对各桥型进行技术经济性分析,为中等跨径跨线桥梁的设计及UHPC、CFRP等新材料的应用提供参考。分析结果表明:简支组合桁梁动力特性较好,刚度、稳定性适中;连续组合桁梁构件强度较均衡,材料利用率相对高,但竖向刚度相对较小;系杆拱桥竖向刚度相对较大,但横向稳定性相对差;斜拉板桥竖向刚度相对大,横向稳定性相对好。在相同条件下,简支桁梁、系杆拱桥、连续桁梁、斜拉板桥的材料造价比值为1∶1.02∶0.97∶1.83,连续组合桁梁的经济性最优,而斜拉板桥相对差。组合桁梁桥施工性能更优,而系杆拱桥与斜拉板桥景观效果更为突出。

To promote the application of rectangular ultra-high-performance concrete-filled steel tubular(UCFST)composite structures,and promote the development of lightweight and assembly technology of bridge structures,the design and study were conducted on medium span through type UCFST bridges based on a certain overpass project of Shanghai-Wuhan expressway.It is proposed to use ultra-high performance steel-concrete composite structures as the main load-bearing components of bridge.That has excellent performances(e.g.,high bearing capacity,high durability,convenient construction,and high degree of assembly),which meet the current development needs for lightweight and thin-walled bridge construction.Based on the engineering construction conditions,3 design bridge type were proposed,which were the composite truss bridge,tied arch bridge,and cable-stayed bridge.The bridge design innovatively adopted the CFRP suspender,CFRP prestressed reinforcement and cold-formed crimped U-shaped beam with UHPC bridge deck structure.The strength,stiffness,stability and dynamic characteristics of each design structure were analyzed by using finite element model.The design results met the requirements of the specification.The technical and economic analysis on each bridge type was carried out to provide a reference for the design of medium span overpass bridges,and the application of new materials(e.g.,UHPC and CFRP).The result indicates that for the simple supporting composite truss girder,the dynamic characteristic is better,and the stiffness and stability are moderate.For the continuous composite truss girder,the strength is relatively balanced,and the material utilization rate is relatively high,but the vertical stiffness is relatively small.For the tied arch bridge,the vertical stiffness is relatively large,but the lateral stability is relatively poor.For the cable-stayed plate bridge,the vertical stiffness is relatively large,and the lateral stability is relatively good.Moreover,under the same conditions,the material-cost ratio of simple supporting truss,tied arch bridge,continuous truss girder and cable-stayed bridge is 1∶1.02∶0.97∶1.83.Therefore,the economy of continuous composite truss is the best,while that of cable-stayed plate bridge is relatively poor.The construction performance of composite truss bridge is better,and the landscape effect of tied arch bridge and the cable-stayed plate bridge is more prominent.