既有桥梁上加设大跨度钢梁吊装施工技术

在既有立交桥范围内空间环境复杂、限制条件诸多、作业困难的架梁作业中,充分利用钢箱梁具有抗弯能力强的特性,提出了运用杠杆原理进行困难复杂环境下的钢梁吊装的方法.通过将墩间二段钢箱梁预先接长成一段,取消跨中位置安装用的门吊,加装构造简单的杠杆实现梁段内的“吊点”外延,采用钢箱梁非对称悬臂状态下运输,以及用跨墩门吊进行门吊作业范围以外钢箱梁的吊装等措施,完成了既有立交桥上加设大跨径钢箱梁的安装作业.

The Construction Technique for Hoisting Long Span Steel Beam on Existing Bridges

The paper proposes a method for hoisting steel beam with the leverage principle in difficult and complex environment.The method can take full advantage of the high bending strength property in steel box beam during the construction of interchange bridge,which the environment is complex with many limitations and the hoisting work is difficult.The new method has several steps.Firstly,joining the two steel box beams between a pier together and cancelling the gantry crane on the mid-span used in installation location.Secondly,installation of a simple leverage to achieve ＂hanging point＂ of beam extended.Finally,carrying the beam in the asymmetric cantilever state and hoisting it with gantry cranes over piers outside the scope of the normal gantry crane.