摘要
汝郴高速赤石特大桥为四塔双索面斜拉桥,跨度为165m+3×380m+165m,主梁为预应力混凝土结构,采用单箱四室箱形截面。该桥主梁采用前支点挂篮悬浇施工,原合龙方案的合龙顺序为先边跨、再次中跨、最后中跨,在成桥收缩徐变10年后,该合龙方案下的塔偏量较大。为避免桥塔偏位过大致使桥梁结构受力和耐久性受到影响,提出顶推合龙方案,变更主梁合龙顺序为先边跨、再中跨、最后次中跨。采用BDCMS软件建立全桥有限元模型,对成桥收缩徐变10年后,2种方案的塔偏、桥塔应力、主梁应力、斜拉索索力等进行对比分析。结果表明:采用顶推合龙方案,大大减小了桥塔偏位,使塔偏更"居中",对主梁应力及斜拉索索力影响更小,使桥塔左、右缘应力更均衡,有利于抵抗后期活载影响,对桥梁结构整体受力有较大改善。
The Chishi Bridge on Rucheng-Chenzhou Expressway is a cable-stayed bridge with four pylons, double cable planes and with span arrangement 165 m＋3×380 m＋165 m. The main girder of the bridge is the prestressed concrete structure having the section of four cells and single box. The girder was cantileveredly cast, using the front support form travelers and the closure se- quence of the girder in the original closure scheme was that the girder over the side spans was to be closed first, over the secondary central spans was then and over the central span was finally. How- ever, after 10 years of the shrinkage and creep of the completed bridge, the offsetting amounts of the pylons according to the scheme would be great. To avoid the adverse influences from the exces- sive offsetting of the pylons on the structural force conditions and durability of the bridge, a new scheme of pushing closure was proposed, the closure sequence of the main girder was changed into the sequence that the girder over the side spans was to be closed first, over the central span was then and over the secondary central spans was finally. The software BDCMS was used to set up the finite element model for the whole bridge of the bridge and the offsetting amounts and stress of the pylons, the stress of the girder and the stay cable forces in the two schemes after 10 years of the shrinkage and creep were compared and analyzed. The results of the analysis show that the scheme of pushing closure can greatly reduce the offsetting amounts of the pylons, can make the offsetting of the pylons in better central positions, the influences of the scheme on the stress of the girder and stay cable forces are little and can make the stress in left and right sides of the pylons more balanced. The scheme is conducive to counter the influences of the future live load and can greatly improve the integral structural force conditions of the bridge.
出处
《桥梁建设》
EI
CSCD
北大核心
2016年第1期117-121,共5页
Bridge Construction
关键词
多塔斜拉桥
预应力混凝土结构
箱形梁
顶推
有限元法
合龙方案
multi-pylon cable-stayed bridge
prestressed concrete structure
box girder
pushing
finite element method
closure scheme
