Abstract:

With the complex interaction between wind and structure, the long-span roof structure belongs to wind-sensitive structures and the wind load becomes the main problem of the structure design. Taking a long-span roof of power plant as research background, the vibration characteristics of the structure were obtained. Based on the wind pressure spectrum fitting and the proper orthogonal decomposition（POD） reconstruction principle of wind pressure time-history, a modified frequency domain analysis method was presented. This method used the wind pressure data obtained in wind tunnel tests to establish the overall wind pressure model for roof, and turned it into wind pressure spectrum through fast Fourier transform （FFT）. Then the wind-induced dynamic response of roof structure was obtained based on the accurate fitting of wind pressure power spectrum, and the dimensionless formula of wind pressure spectrum was derived. Finally, the distribution characteristics of the root mean square （RMS） values of structural displacement and acceleration were studied to get the distribution characteristics of the wind-induced vibration coefficient of the roof. The results show that modified frequency domain method, which abandons the quasi-steady assumption, has higher reliability, and can be used as references for the wind-resistant design of long-span roof structures.

Key words: long-span roof, stochastic theory, wind pressure spectrum fitting, modified frequency domain method, wind-induced dynamic response, wind-induced vibration coefficient