Spectral model of fluctuating wind pressure on grandstand roofs with consideration of signature turbulence

Based on wind tunnel tests of grandstand roofs with different pitches, the characteristics of fluctuating wind pressures were investigated, aiming to get available spectral model of fluctuating wind pressure, which was necessary in wind vibration analysis during simulating wind loading. The wind pressure spectra on roofs were obtained by spectral analysis. It is found that the shapes of wind pressure spectra of frontal taps are close to that of wind velocity spectra, but quite different from results of taps on the leeward part of roof which should be dominated by vortex shedding. The wind pressure spectra on roofs are modeled with the combination of approaching wind spectra and power spectrum representing vortex shedding, with the factors representing their contribution. The cross spectra between two points can be reached from an exponential function of the reduced frequency, the decay constant is decided from the wind tunnel data. In order to verify the availability of wind pressure spectra models on grandstand roofs and highlight the influence of signature turbulence, wind-induced vibration analysis in time domain for grandstand roofs with truss structure are carried out. The input time series are wind tunnel data, simulated wind pressure time series based on the spectral model of this paper and the wind pressure time series based on quasi-steady assumption respectively. The peak and fluctuating responses based on this paper's model of wind pressure spectra are close to that of wind tunnel results, while the results based on quasi-steady assumption has maximum error of 10%-15% for peak responses, and 30%-40% for fluctuating responses. These results reveal that the effect of signature turbulence can not be ignored during modeling of fluctuating wind pressure spectra.