Experimental Research On Large-Span Steel Roof Structure

Large-span arch-supported reticulated shell structure is a new hybrid structural system based on features of reticulated shell and arch structure. It can improve the bearing performance and increase the span of structure by the way of using the advantages of one structure to make up the shortcomings of the other structure. The subject studied is a 1:20 reduced scale model of Nanjing Olympic Sports Center's Main Stadium. On the basis of experiment and analysis results, the cooperating performance of oblique crossing arch-supported structures is studied. The relevant contents are as follows: The whole static test is introduced including the design of reduced scale model, loading unit and the test process. The test results indicate that the structural response under design load is linear property. The comparison between analysis results and tests results shows that the analysis model assumed is appropriate. The repeated loading process by jacks is proved to be successful. The method can control not only the magnitude of load but also the displacement under the condition of maintaining the load. This method makes it possible to study the stability quality of model by supply repeated loading to model within elastic range. The comparison between linear and nonlinear results indicates that the geometric nonlinearity has little influence on the deformation and internal force of structure under design load case. Besides the member having maximum stress is still in elastic range and will not affected by material nonlinearity. But with the increase of load, the nonlinear performance is more obvious. The ultimate bearing capacity of structure should take geometric and material nonlinearity into consideration at the same time. The variety of constraints of roof, section size of connecting bar and stiffness of arch structure may have effect on displacement of structure, stress of members etc. The influences are carefully studied in this paper. The elastic response of structure under frequent seismic actions and the elastoplastic response under infrequent seismic actions are calculated by the method of time-history. The results show that the inclined arch has great displacement both in X direction and vertical direction. The checking calculation of deformation in these directions should be carried out in anti-seismic design. And the material nonlinearity should be included in infrequent seismic analysis. The elastic buckling analysis and nonlinear stability analysis indicate that it is necessary to consider the effect of concrete structure below in stability analysis. The differences between local buckling and ultimate collapse are carefully studied and some determinant factors are presented.