甬江铁路特大桥施工控制

甬江铁路特大桥为主跨468 m半飘浮体系双塔双索面混合梁铁路斜拉桥.混凝土梁采用满堂支架现浇,钢箱梁采用悬臂拼装,桥塔塔柱采用全自动液压爬模施工.为保证施工过程安全、快捷,成桥后线形和内力满足设计及高速列车运行的要求,采用基于无应力状态理论的全过程几何控制法进行施工控制,正装迭代计算采用TDV软件进行.结果表明:基于无...

Construction Control for Yongjiang River Railway Bridge

The Yongjiang River Railway Bridge is a semi-floating hybrid girder cable-stayed bridge with a main span of 468 m.The bridge has two pylons,with stay cables arranged in double cable planes.The concrete girders were cast in-situ on full scaffoldings,the steel box girders were assembled in cantilevers,and the pylons were constructed by automatic hydraulic climbing formwork.The structural monitoring and control during construction was carried out by the full process geometry control method based on stress-free state theory,with intent of ensuring the safe and rapid construction and allowing the geometry and internal forces of the completed bridge to meet the design requirements and the service conditions for high-speed trains.The forward iterative analysis was conducted by TDV software.The results show that deviations were rectified based on the stress-free state calculation,utilizing the elevation of the formwork,rotation angle between adjoining segments,stress-free cable lengths and girder-end cable forces for adjustment,if necessary,adding water tanks for counterbalancing.The influence of ambient temperature on the geometries of the girders and pylons was reduced,thereby realizing the all-weather construction and curvature-free closure.After closure,the maximum elevation deviation of the main girder was 73 mm and the maximum pylon offset was 11 mm.In construction process,stresses in typical concrete cross-section were between -8.10 and -2.55 MPa,stresses in the cross-section of steel-concrete joint section were about -6.14 to -1.18 MPa,and the stresses in the stress structure were within the range of -28.97 to -6.45 MPa.The error of cable forces was less than 5%.The geometries and internal forces of the main girder and pylons meet the design requirements.