Comparison Between Time-domain Approach And Frequency-domain Approach In Analysis Of Wind-induced Response Of Long Span Roofs

Long-span roofs are generally light,wide-span,flexible,low damping and low natural frequency. They are prone to wind and the wind load is one of their most important loads to control the structural design .During the existing norms of the wind load of building structures, it is still not perfect of the method to get parameter values of the long-span space structure's wind-resistant design. The existing calculation method about the wind-induced responses consists of Frequency domain analysis and Time-domain analysis. Respectively analyzing the wind-induced responses of long-span roofs in frequency domain and time domain are processed in this thesis, and their comparative analyses also are included.The author at first introduces the newest research at home and abroad on the wind-induced response of long-span roofs .Based on the time histories of wind pressures of long-span roofs surface nodes from the wind tunnel tests, distribution of mean wind pressure coefficient of long-span roofs is analyzed. In frequency domain, the wind-induced responses of long-span space structure are computed by the Fast Complete-Quadratic-Combination method and Square Root Sum Square method, and the impact of modes interception and modes coupling to wind-induced response are analyzed. In Time-domain, the time histories of the wind-induced responses of long-span space structure are computed by two methods. the first one is that the time histories of wind load are discrete interpolation by proper orthogonal decomposition (POD) , then its time histories are computed by Time-domain analysis; the other one is that the wind load space vector are computed by proper orthogonal decomposition, and Block Ritz vector superposition are reduced the structure degrees of freedom, then its time histories are computed by Time-domain analysis. The wind-induce responses of long-span roofs are reached on the base of statistics of the time histories from the above mentioned methods. Compared with the results from frequency domain analysis and time domain analysis, some valuable conclusions are achieved...