沪通长江大桥天生港专用航道桥弦杆制孔精度控制技术

摘要

沪通长江大桥天生港专用航道桥为(140+336+140) m刚性梁柔性拱桥,主梁为带竖杆的华伦式桁架,横向采用三片主桁结构.钢桁梁弦杆为典型的箱形整体节点构造,接头较多,孔群空间关系复杂,为保证弦杆钻孔精度,腹板孔群制孔时,杆件组焊并修整合格后,首先将杆件吊至高精密的划线平台处进行整体划线,然后利用专用整体节点杆件双机联动立柱式数控钻床进行钻制.顶、底板及横梁接头孔群采用成熟的划线工艺和高精度样板钻制.斜向接头板组装时,首先采用斜向接头板先孔法,然后用高精度定位样板组装.实践表明,弦杆制孔精度控制技术及孔径偏差控制措施,有效地保证了弦杆的钻孔精度和孔群的相对位置关系.%The Tianshenggang Channel Bridge of Hutong Changjiang River Bridge is an arch bridge with rigid girder and flexible arch and with span arrangement of (140+336+140)m.The main girder is a Warren truss structure with vertical members, formed of three truss blocks transversely.To ensure the perforation accuracy of the chords, during the making of the hole groups on the webs, the members were lifted to the marking platform with high precision to mark the locations of the holes after the members were welded and verified qualified.Then the two column CNC Drilling machines in tandem for the special members with integral nodes were used to make holes.The group holes in the top and bottom plates and the joints of the cross beams were made by mature marking technique and high-precision model drill.During the assembly of the oblique joint plate, the holes were first made on the oblique joint plates, and then the oblique joint plates were assembled by high-precision positioning plates.The practice proves that the perforation precision control technique and hole dimension difference control measures used effectively ensure the perforation precision of the chord and the relative locations of the hole groups.