Study On Key Construction Technologies Of Large Cantilever Steel Structure

Along with our country's high-speed economic development, high-rise building design is increasingly to comprehensive multi-purpose development in order to satisfy the functional requirements of high-rise buildings and urban beautiful requirements. High-rise building structure also is further complicated, its characteristic is higher, more complex shape, more comprehensive of function. Multi-functional requirements caused multi-functional structure size and structure form, such as belt conversion layers structure, joint structure, Incorporated into the vertical and Cantilever Structure, Enhancement layer structure, plane irregular structure etc. Combination of these types of structure is used more in recent years. These new forms of building structures Give us a fresh sense of visual impact, at the same time it also makes a lot of problems to the architectural structure construction.This paper takes the construction mechanical analysis as means, Shenzhen Stock Exchange Operations Center as the research object, the key technical problems during the construction process of the large cantilevered structure-uplift podium have been studied, and the following conclusions are obtained:(1)According to a variety of mechanical problems and technical difficulties existing in the construction process,determine the general construction scheme of the podium, through simulated the construction process, optimize the construction program. The research showed that it had no effect on the structure to consolidate part of the construction steps of theory construction scheme, the actual construction scheme to be used is safe and feasible, and to some extent, shorten the construction period, save construction costs.(2) Put forward some key technologys during the installation process of the podium, and make some analysis and studies, i) It analyzes welding deformation of the large steel joint during its in-situ upper air installingprocedure and study the impact of welding deformation of precise location when splicing the joint at high altitude and determine the welding scheme. to adopt a "bottom-up, first welding vertical weld, then symmetrically welding horizontal weld" principle when assembling the node at high altitude is beneficial for displacement control; ii) Analyse the impact of towers construction on the podium when not unloading, when the compressing settlement is not considered,the camber value maybe slightly larger---if the prodiums are constructed with certain camber value,at the time when the construction is done and the assembly jig is not unloaded yet,the real camber value may be larger than design value.(3) Put forward some key technologys during the unloading process of the supporting jig, and make some analysis and studies:i) In order to meet the needs of unloading,sandbox test are carried out, the experimental results show that the sandbox can be used as the unloading tool. To simulate unloading conditions of the podium, fullload and overload testing are carryed out, and the technical parameters of the reasonable sandbox are determined; ii) Analyse the cracking problem of the podium concrete floor the when unloading. If concrete is poured before the prodiums are unloaded,concrete on the top of the prodiums may crack in the unloading.it will be better if the pouring of floor concrete which uplifts the promiums are done after the unload of the assembly jig.(4)The study of contrast the project monitoring results and the theoretical analysis. Around ultimate design goal of the coordinate and the internal force distribution, of the stress and displacement of control section in different stages during the lifting process of the steel structure were monitored, and were compared with the numerical simulation results. In the monitoring, the stress monitoring results are influenced by factors from aspects,and maybe unable to reflect the real sterss level of the structure,so the controllability of stress in the constructing is relatively low;but the displacement monitoring are influenced by less factors,so that it gets higher precision and matches the calculation perfectly,which means the controllability of structure deformation is relatively high.