马鞍山长江公路大桥左汊主桥北边塔塔柱施工技术

马鞍山长江公路大桥左汊三塔悬索桥边塔为门式C50混凝土结构,塔柱高165.3m,分37个节段施工,第1节段高4.7m,第2～36节段为标准节段(高4.5m),第37节段高3.1m。1～3节段采用脚手架搭设施工,4～37节段采用液压爬模施工。塔柱施工关键技术有:劲性骨架制作及安装,主筋吊装,钢筋定位,钢筋保护层控制;模板间错台控制,模板拉杆设计,模板精确定位,混凝土面局部凹凸不平控制,上、下2节段混凝土面接缝控制;混凝土配合比、输送、布料、振捣及养护。实践表明,通过精心设计与组织施工,钢筋保护层厚度、混凝土面局部凹凸和新老混凝土错台等均得到了有效控制,研制的混凝土多溜槽系统成功解决了混凝土布料不均等问题。

Construction Techniques of North Side Tower Columns of Left Main Bridge of Maanshan Changjiang River Highway Bridge

The north side tower of the left main bridge(a three-tower suspension bridge) of Maanshan Changjiang River Highway Bridge is a C50 concrete portal structure.A column of the tower is 165.3 m high and is constructed in 37 lifts,of which the 1st lift is 4.7 m high,the 2nd~36th lifts are standard lifts(each 4.5 m high) and the 37th lift is 3.1 m high.The 1st~3rd lifts are constructed on the scaffoldings and the 4th~37th lifts are constructed by the hydraulic climb formwork.The key techniques applied to the construction of the columns of the tower include the fabrication and installation of steel frame skeleton,lifting and installation of main reinforcement,positioning of reinforcement,control of concrete cover,control of staggering between formwork,design of tie rods for the formwork,accurate positioning of the formwork and control of local evenness of concrete surface,control of joints between the upper and lower lifts,mix proportioning design,delivery,spreading,vibrating and curing of concrete.The construction practice of the columns of the tower proves that through the careful design and construction organization,the thickness of the concrete cover,the local evenness of the concrete surface and the staggering of the new and old concrete have been effectively controlled and by means of the specially developed concrete multi-chute system,the major problem like the non-uniform spreading of the concrete has been successfully resolved as well.