Optimization Study On Large Span Steel Roof Structure And Its Construction

With the sustainable and rapid development of the national economy,the progress of science and technology and the development of software have greatly promoted the optimization of large-span structure.As an important system of large span stell structure,truss plays an important role.As a type of truss structure,steel roof structure has the characteristic of big rigidity,light weight,strong earthquake resistance,simple structure,convenient disassembly and installation and low cost.Therefore it widely used in many large span structures in foreign countries in 20 th century.There are also many projects adopt steel roof structure.But the analysis of the structure optimization and construction optimization is still in the initial stage and has gap compare with the mature construction technology in foreign countries,especially in consideration of bar loading sequence and and the transformation of the rigidity of the joint,so it is necessary to carry out further research.This article proposed an optimization method of steel roof truss based on structural constraint conditions and take Tianjin Air bus A330 paint hangar as example which USES only half the amount of steel as other structures.Start with a 72 meters span steel structure construction optimization example analysis,according to the engineering construction plan,and use Midas Gen finite element software birth-death element to make numerically simulated of project whole process of engineering installation and forming.By analyzing and comparing the finite element model before and after the construction optimization,it was found that the maximum stress after the optimization was 76.73% of the pre-optimization stress,and do the field test on the paint spraying hangar.The reliability and accuracy of the construction scheme are verified through the comparative analysis of experimental data and finite element simulation.The effects of constraint conditions on the mechanical properties of steel roof frame in service are studied at the same time.Take Tianjin Air bus A330 paint hangar as example to analysis.By analyzing and comparing the finite element model before and after the construction optimization in the service stage of steel roof,the maximum stress of the whole structure under the optimized load combination is 77.5% of the unoptimized structure stress,and field test is conducted.Through the comparison of finite element simulation and experimental data,it is found that the optimization method of steel roof construction with structural constraint condition changes can reduce the structural stress in service stage.Finally to study the the optimization method of steel roof structure based on load distribution.Do numerically simulated to a 72 meter span steel structure and analysis different stress state of the structure when the upper chord beam is subjected to intersection load and node load.It is found that the load distribution mode has a great influence on the stress of the beam directly in contact with it and bear intersection stess directly.The maximum stress of bearing the intersection load is 1.26 times that of the node load,but the load distribution has little influence on the whole structure.