| As a highly mechanized building machine,the hydraulic jacking formwork system of super high-rise building is widely used in the construction of modern super high-rise buildings.As a platform for material accumulation and personnel construction in super high-rise building,the invention and use of top formwork greatly improve the speed of super high-rise building.In practical engineering construction,the design of top formwork structure is often affected by the engineering experience of designers.The designed structure often has some problems,such as conservative structural safety,unreasonable structural stress,excessive structural self weight and so on As the core of super high-rise building technology,the safety and rationality of top formwork structure directly determine the quality of super high-rise building,so the optimization of top formwork structure is particularly important.In this paper,the top formwork structure used in a super high-rise building construction project in Xi’an is taken as the research object.The wireless strain monitoring system is used to monitor the stress of the top formwork structure under various working conditions,and the actual stress value of the top formwork structure under different working conditions is obtained.The finite element software is used to analyze and monitor the stress of the structure under the corresponding working conditions,and the simulation results are compared with the measured stress of the top mold,so as to verify the correctness of the finite element method.The finite element software is used to simulate and calculate the stress and deformation of the structure under the load combination of the ultimate design values of the bearing capacity(1.35d+0.981 and 1.2D+0.981+1.4W),and the calculation results are compared with the steel structure design code.It is concluded that the steel frame structure has insufficient strength and stiffness and structural self weight,while the supporting structure has structural safety There are many problems,such as too large total reserves,too large self weight of structure and serious consumables.Therefore,two different structural optimization methods are selected for the steel frame structure and support structure of the jacking formwork system studied in this paper.Aiming at the problems of steel frame structure in top formwork,the topology optimization method is used to optimize it.The corresponding finite element software is used to establish the primary model of topology optimization.After the constraints and loads are imposed on the initial model,the topology optimization of the initial model is carried out by means of computer iteration.After the optimization results are obtained,a new steel frame structure is built with section steel according to the principle of manufacturability.In view of the problems existing in the supporting structure of the top formwork,the full stress method of the section optimization method is selected to optimize the section of the member in the structure.On the premise of meeting the safety and normal use of the supporting structure,the optimization purpose of reducing the weight of the structure can be achieved by reducing the section size of the bar in the top formwork supporting structure.The optimized top mold structure is substituted into the finite element software for mechanical analysis,and the results of finite element analysis are compared with the results of structural analysis before optimization.Compared with the original structure,the new structure has the advantages of light weight,high strength and stiffness,and reasonable structure stress.Therefore,the optimization method and the final optimization results can provide reasonable suggestions and data for the design and construction of the top formwork structure,which has a certain engineering application value. |
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