摘要
贵州平塘特大桥为(249.5+550+550+249.5)m三塔双索面叠合梁斜拉桥,为提高上部结构施工效率,将主梁节段散拼优化为钢梁整体节段吊装,每个湿接缝单独浇筑优化为一次浇筑2个湿接缝。采用MIDASCivil建立大桥有限元模型,对主体结构应力、位移,钢梁整体节段吊装变形和桥面吊机前支点处钢横梁局部应力进行计算分析。结果表明:采用优化后的上部结构施工方案,平均一个节段5~6d施工完成,工期缩减约一半;施工期间钢梁、混凝土桥面板最大应力均满足规范要求,斜拉索安全系数大于2.0,考虑10年收缩徐变后,桥塔塔顶偏位和主梁竖向位移满足设计要求,恒载预拱度较小;钢梁接头处局部变形差较小,翘曲不明显,不影响钢梁拼接,桥面吊机前支点力引起的支撑处钢横梁局部应力较小,结构安全。
The Pingtang Bridge in Guizhou Province is a three-pylon composite girder cable-stayed with spans of 249.5,550,550 and 249.5 m.The stay cables are arranged in double cable planes.In order to improve the construction efficiency of the superstructure,the original design of making the girder section take form by assembling individual components is optimized to the one of prefabricating a monolithic steel girder section for lifting and erection.And in the original scheme,each wet joint is cast individually,casting one wet joint each time,but after optimization,two wet joints are cast each time.The software MIDAS Civil was used to establish the finite element model of the bridge,to calculate and analyze the stresses and displacement of the main structure,the deformation of the monolithic steel girder section during lifting and erection as well as the local stresses in the steel cross beams at the front supports of the deck crane.The results show that following the superstructure construction scheme after optimization, the average construction time for a girder section is about 5 or 6 days,about half of the time in the original scheme.During construction,the maximum stresses of steel girder and concrete slabs can meet the requirements of specifications,and the safety factor of stay cables is greater than 2.0. Taking into account the 10-year shrinkage and creep,the offsetting amount at the pylon tops and the vertical displacement of the main girder can meet the design requirements,and the pre-camber against dead loads is small.The difference of local deformation at the joints of the steel girder sections is minimal,and warpage is not obvious,which will not influence the assembling and connecting of the steel girder sections.Meanwhile,the local stresses in the steel cross beams at the supports caused by the front-support force of the deck crane is small,and the structure is in a safe state.
作者
余毅
彭旭民
YU Yi;PENG Xu-min(China Railway Bridge Science Research Institute,Ltd.,wuhan 430034,China;StateKey Laboratory for Health and Safety of Bridge Structures,wuhan 430034,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2019年第A01期104-108,共5页
Bridge Construction
基金
贵州省科学技术厅黔科合重大专项([2016]3013)~~
关键词
斜拉桥
叠合梁
钢-混结构
整体节段
吊装
湿接缝
混凝土浇筑
施工优化
cable-stayed bridge
composite beam
steel-concrete structure
monolithic section
lifting and erection
wet joint
concrete pouring
construction optimization
