Analysis Of Wind Resistant Behavior And Ultimate Load Carrying Capacity Of Light-weight Steel Structures

Light-weight steel portal frame structures have been widely used in industrial buildings in southeast coastal areas of China where typhoon often visit. As steel portal frame structures are commonly light-weighted and flexible, they are very sensitive to wind loading. Consequently, analysis of wind resistant behaviors and the ultimate load carrying capacities of such structures is of importance to the building design and construction.The wind-induced failure modes and their internal mechanisms for light-weight steel structures are first analyzed in the paper, which indicates that the wind-induced failure can be categorized to the failure of maintenance structure and failure of load-bearing structure. However the failure generally starts from the maintenance structure. According to the failure mechanism of light weight steel structures in wind disasters, the flow chart for ultimate load-carrying capacity analysis of light-weight steel structures is established, with an extra attention focusing on the maintenance structure.Secondly, static analysis, mode analysis and dynamic time-history analysis are carried out to a two-bay steel portal frame with semi-rigid connections using the finite element method. The obtained results indicate that the rotational stiffnesses of beam-column connections have significant influence on the internal-force distribution, global stiffness, deformation and also the self-vibration period and wind-induced dynamic responses of the structure. Some design suggestions are recommended on the basis of further analysis and discussion.Finally the pushover method which has been widely applied in the seismic analysis is introduced to wind resistance analysis of light-weight steel structures. Using the method, the structural behavior, non-linear internal forces and displacements, and also the ultimate load-carrying capacity and failure modes of the structure under strong wind loading can be readily obtained through the corresponding analysis. The pushover method is simpler that the traditional elastic-plastic dynamic analysis method as the time-consuming stochastic wind-load simulation and time-history dynamic computation are avoided.