钢箱梁拼装及桥位焊接的监理

Supervision of Assembling and Bridge Site Welding of Steel Box Girder

为使钢箱梁桥位焊接后能符合设计给定的线形,从预拼装阶段开始,控制各项工序的质量。钢箱梁的制造和预拼装可分为长线法和短线法。悬索桥的钢箱梁吊装时,钢箱梁的空间位置由主缆线形和吊索长度确定,钢箱梁吊装后其线形已经确定,不可能在吊装过程中或吊装后再行调整;而斜拉桥则在钢箱梁吊装时,通过施工监控逐个调整吊装梁段的索力、远点的标高和里程实现设计给定的线形。介绍斜拉桥钢箱梁吊装过程中吊装梁段的调整方法、合龙段吊装前后的注意事项。以西堠门大桥为例,说明钢箱梁桥位焊接施工期的监理要点。

To ensure that the steel box girder welded at bridge site can meet its designed geometry, the quality of various working procedures for the girder should be well controlled from the early stage of pre-assembling. A steel box girder can be manufactured and pre-assembled either by the long line or short line match method. For the lifting and installation of the steel box girder of a suspension bridge, the spatial position of the girder is determined by the geometry of the main cables and length of the suspenders. Once the girder is installed, the geometry of the girder has already been determined and it is impossible to further readjust the geometry of the girder during or after installation of the girder while for the installation of the steel box girder of a cable-stayed bridge, the designed geometry of the girder is generally realized through adjustment of the cable forces, far-point elevation and mileage of each installed girder block by means of construction monitoring and control. The methods for adjustment of the installed girder blocks in course of installation of the steel box girder of the cable-stayed bridge and matters of attention before and after the installation of the closure block of the bridge are presented. By way of example of Xihoumen Bridge, several key points of the supervision during the welding construction of the steel box girder at bridge site are narrated.