摘要
平潭海峡公铁大桥3座通航孔斜拉桥的6个桥塔墩均采用哑铃形高桩承台,元洪航道桥N04号墩承台平面尺寸为81.0m×33.0m,厚9.0m,混凝土方量为18104m3。为节省造价,桥塔墩承台施工均利用主体防撞箱作围堰侧板,增加底板、系梁桁架、单壁隔舱、内支撑等施工结构,组成双壁钢吊箱围堰。单个围堰总长96.8m(含防撞梁),宽37.32m,高16.6m,入水深度12.88m,最大波浪力约20000kN。哑铃形围堰系梁区不封底,围堰分区抽水,承台分区分步施工,围堰从吊装下放、抽水至承台施工完成共有8个控制工况,采用MIDAS Civil和MIDAS FEA软件建立各施工阶段有限元模型,分析围堰、封底混凝土及已浇筑承台受力状况。计算结果表明,围堰各部分结构及已浇筑承台应力均满足规范要求,设计方案可行。
The Pingtan Straits Rail-cum-Road Bridge consists of three cable-stayed bridges crossing navigation channels.The six pylon piers of the three bridges are mounted on dumbbell-shaped pile caps supported by pile foundations.The pile cape of pier N04of Yuanhong Navigational Channel Bridge measures 81.0mby 33.0m,9.9min depth,consuming 18104m3 of concrete.To cut down costs,the anti-collision enclosures were employed as the walls of the cofferdam during the construction of the pile caps.Based on which,base plates,tie trusses,partitions and inner bracings were added to form double-wall steel box cofferdams.An individual cofferdam measures 96.8m(total length,including anti-collision beams)by 37.32m(width)and 16.6min height,which has a draft of 12.88mand wave resistance of 20000kN.The tie truss region of the dumbbell-shaped cofferdam did not require base sealing.The cofferdam was divided into zones to facilitate water pumping,and the pile cap was constructed zone by zone.The construction from hoisting and launching of cofferdam and water pumping to the completion of pile cap fell into 8control stages.The loading conditions of the cofferdams,base sealing concreting and the pile cap concreting were simulated and analyzed by MIDAS Civil and MIDAS FEA.The results of computation indicated that the stresses in different components of the cofferdams and completed pile caps could meet the code requirements,and the design scheme was feasible.
作者
徐启利
XU Qi-li(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;State Key Laboratory for Health and Safety of Bridge Structures,Wuhan 430034,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2021年第1期115-120,共6页
Bridge Construction
关键词
斜拉桥
哑铃形承台
吊箱围堰
防撞箱
系梁桁架
单壁隔舱
围堰设计
cable-stayed bridge
dumbbell-shaped pile cap
steel box cofferdam
anti-collision enclosure
tie truss
single-wall partition
cofferdam design
