铁路大跨度劲性骨架拱桥外包混凝土浇筑方案分析

为保证一座新建铁路主跨337 m上承式劲性骨架混凝土拱桥主拱圈外包混凝土安全顺利施工,采用MIDAS/Civil建立施工阶段三维有限元模型,分析了不同纵向分段、横向分环浇筑方案对劲性骨架受力及挠度的影响.研究结果表明:采用多工作面浇筑可显著降低拱脚应力,改善主拱变形,但增加工作面对拱顶受力有利也有弊;增加截面横向分环可有效降低结构应力;综合考虑外包混凝土浇筑过程中的结构应力、变形、建设工期和大型临时设施的成本,采用三环六面法浇筑外包混凝土方案.

Analysis on Pouring Scheme of Surrounding Concrete for Railway Large Span Arch Bridge with Stiff Skeleton

In order to ensure the safe and smooth construction of the main arch ring on a newly-built railway deck type stiff skeleton concrete arch bridge with a main span of 337 m,the three-dimensional finite element model of the construction stage was established by using MIDAS/Civil.The influences of different longitudinal segmentation and transverse ring division pouring schemes on the stress and deflection of the stiff skeleton were analyzed.The results show that multi working face pouring scheme can significantly reduce the stress of arch foot and improve the deformation of main arch,but there are advantages and disadvantages in increasing the stress of the working face on the vault.The structural stress can be effectively reduced by increasing the cross-section transverse ring division.Considering the structural stress,deformation,construction period and cost of large-scale temporary facilities in the pouring process of surrounding concrete comprehensively,the method of three-ring six-face is adopted to pouring the surrounding concrete.