铁路系杆拱桥设计研究

Research on the Design of Railway Tied Arch Bridge

研究目的:系杆拱桥采用系杆承受拱的推力,在桥梁建筑高度受到限制或桥址地质不良地区,而又需要较大跨度时,系杆拱是较合理的桥式之一。成都三环路立交特大桥是国内首座大跨双线铁路预应力混凝土系杆拱桥,本文针对该立交特大桥双线铁路预应力混凝土系杆拱的结构特点及受力特性进行分析研究与检算,为施工提供指导。研究结论:成都三环路立交特大桥是国内首座大跨双线铁路预应力混凝土系杆拱桥,通过静动力分析表明该桥各项指标都满足规范要求;但拱梁结合部受力复杂,设计时采用三向预应力结构,主梁在梁端处进行了加宽加高、腹板加厚处理;因结构复杂局部存在一定的应力集中现象,通过研究和计算,将国内外新的科研成果和理论运用在本桥的设计中,进一步扩大了系杆拱结构在铁路桥梁建设上的应用,可为今后类似桥梁的设计提供借鉴。

Research purposes： As the tie - arch bridge uses tie bar to bear the push force of the arch, so it is one of reasonable bridge types under the condition the bridge height is limited or the bridge site lies in the unfavorable geological area. The super major overpass on the 3rd ring road in Chengdu is the first and largest large - span double track railway prestressed concrete tied arch bridge in China. In this paper, the research is done mainly on the structural features and the characteristics of force bearing capacity of such tied arch bridge for instructing the construction. Research conclusions ：The the static and dynamic analyses of the super major overpass on the 3rd ring road in Chengdu show that all indexes of the bridge meet the code requirements. As the bearing force at joint point of arch beam is complicated, the three - dimensional prestressed structure should be designed, the beam end of main beam should be widened and heightened, and webs should be thickened. The stress concentration happens in some parts because of the complicated structure. Based the research and calculation, the applicable range of tied arch structure in construction of railway bridge is widened by adopting new scientific research achievements and theories at home and abroad and it can provide the reference to the similar works.