摘要
武汉青山长江公路大桥主桥为主跨938 m的双塔双索面全飘浮体系斜拉桥,桥塔采用A形混凝土结构,仅设上横梁、无下横梁,北塔高279.5 m,塔座处两塔肢间距62 m。塔柱采用液压爬模施工,在塔柱悬臂施工过程中,根据塔柱施工线形及塔肢截面弯矩控制需要,在桥塔两塔肢范围内共布置了13道主动临时横撑,临时横撑由牛腿、横撑钢管、起顶系统、钢楔块四部分组成。采用MIDAS Civil软件建立桥塔施工阶段有限元模型,按照以桥塔线形控制为主、内力为辅的原则确定了临时横撑对顶力及最大内力,并根据临时横撑最大内力进行横撑钢管截面配置、牛腿设计。通过分析确定该桥中、下塔柱临时横撑按从中部往两端的顺序拆除,上塔柱临时横撑按照从上端往下端的顺序拆除。
The main bridge of Qingshan Changjiang River Highway Bridge in Wuhan is a two-pylon cable-stayed bridge with a full-floating system.The bridge has a main span of 938 m,with stay cables fanned out in double cable planes.The pylons are A-shaped concrete structures,each having an upper cross beam,but without lower cross beam.The north pylon rises 279.5 m,with the two legs flared out and spaced 62 m apart at the pylon footing.The pylon legs were constructed using hydraulic climbing formwork,in the cantilever casting process of which,13 temporary active late-ral bracings were added and distributed through the full length of the pylon legs to suit the variation of pylon geometry and control the cross-section bending moment.The temporary lateral bracings are made up of brackets,lateral steel tubes,jacking system and steel wedges.The software MIDAS Civil was used to establish the finite element model of the pylons in the construction stage.The construction control focused on the geometry of the pylons,but also with proper concern for the variation of internal forces,based on which the pushing force for and maximum internal force of the temporary lateral bracings was determined,and the latter was drawn on to determine the cross-section configuration of the steel tubes and design the brackets.In the intermediate and lower part of the pylons,the central lateral bracings were dismantled first,and then came the adjacent ones,with the demolition proceeding towards the two ends.In the upper part of the pylons,the temporary lateral bracings were dismantled following a top-down sequence.
作者
赵全成
刘晓波
左小明
ZHAO Quan-cheng;LIU Xiao-bo;ZUO Xiao-ming(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;Engineering Quality Supervision Bureau,Department of Transportation of Hubei Province,Wuhan 430014,China;Department of Transportation of Hubei Province,Wuhan 430030,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2020年第S01期100-105,共6页
Bridge Construction
基金
湖北省交通运输厅科技项目(2017-538-2-1)。
关键词
斜拉桥
桥塔
临时横撑
对顶力
有限元法
横撑设计
cable-stayed bridge
pylon
temporary lateral bracing
pushing force
finite element method
lateral bracing design
