Unloading Construction Technology for Temporary Support of Large Cantilever Steel Structures

If large cantilever steel structures are lifted and installed by elements , then the load status of the whole structure in construction stage will be greatly different from that of design stage due to use of temporary support.The unloading operation for temporary support is critical for structural transition from construction to design condition and also is a very complicated process.In this paper , an area-by-area , symmetric , synchronized and step-by-step unloading technology for temporary support is introduced according to the structural features and site conditions of a specific project.Based on the stress condition and deformation value of the structure during unloading obtained by software analysis , screw jacks are used as the main unloading tool and the well organized unloading operation for temporary support is completed successfully by choosing reasonable unloading sequence.Health monitoring for this steel structure is carried out during unloading , the monitoring results show that both the maximum stress and deformation of steel roof meet design requirement.In addition , safety measurement and emergency plan are also proposed in this paper.