Fast Precision Construction Method of Four-point Lifting for Double-crane Cantilever Hoisting
Based on the mechanics balance principle of four-point lifting for steel box girder segment,and according to the attitude balance characteristic of four-point hoisting state of hoisting segment,a fast precision positioning method is proposed to separate vertical slope and transverse slope orthogonal variables.The correct operation sequence of adjusting the vertical slope first and then transverse slope is determined.The engineering example is applied to matching positioning construction of the cantilever assembly of the steel box girder at the center side of Bridge Ⅱ of Yangtze River Bridge in Jiujiang.The error of segment positioning is less than 2 mm.The control precision of the bridge alignment before the steel box girder is hoisted and closured is over L/10 000.The beam is spliced without sharp corners,and the alignment is smooth.Combined with the practice,the matters needing attention in the cantilever hoisting construction of precision wide segment by using the separation method of vertical slope and transverse slope orthogonal variables are given.
bridgehoistingsegmentfine adjustmentbalancerigid body displacement
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