Comparative Analysis on Construction of Four-Side Suspension Structure in High-Rise Buildings

The three towers of an R&D project all adopt four-side suspension structural system. The suspended structure system is composed of core tube， cantilever truss， and suspended outer frame （davit， steel beam）. The top elevation of the tower structure is 59.9 meters， and each building is upside down with eight layers of frame structure. The external suspended steel columns transmit the force to the cantilever trusses at the top of the tower from the bottom up， and finally from the top trusses to the core structure. Compared with the traditional structure system， the four-side suspended structure system requires higher installation accuracy， more complex force transmission path and higher construction difficulty. The two construction methods determined based on project characteristics and force transfer route are reversed construction method and following construction method. The main control and checking analysis points of reverse construction method are： the design and calculation of the temporary support system of the lower part of the suspended outer frame， the 4th floor and the following floors mixed concrete checking， roof truss construction sequence， steel column pressure-tension force conversion， and steel column axial force calculation of the various stages， construction feasibility analysis and summary. The main control and checking analysis points of the following construction methods are as follows： the design and calculation of the temporary support system under the suspended outer frame， the 4th floor and below mixed concrete floor checking， roof truss construction sequence， steel column pressure-tension force conversion and steel column axial force calculation of the various stages， construction feasibility analysis and summary. Comprehensively comparing different schemes of the construction on convenience， safety， final forming state and other major factors. Whole process simulation and verification are conducted on the construction process， to further contrast the feasibility of different programs，and provide reference for similar projects.