Approximation of fluctuating pressure cross-spectra of dome-like roofs under turbulent flow

ABSTRACT

Large span roof structures have been widely adopted for their good performance in multiple functionalities and innovative designs. However, because of their light weight, wind-resistant design is more urgent than earthquake-resistant design. And further, their long span geometry often results in a weak spatial correlation in pressure distributions and hence makes the estimation of wind loads a difficult task. Spectrum characteristics of wind pressures have been mentioned in several publications; however, there is still little discussion of cross-spectrum characteristics. In this paper, cross-spectra of fluctuating wind pressures on various dome-like roofs are investigated under a suburban terrain flow. By examining separately the root-coherence function and the phase function, approximation models of both functions are proposed in terms of the rise/span ratio based on certain simple but efficient assumptions. Once the two functions are simulated in good agreement with experimental results, the cross-spectra, or the co-coherence function, can be simulated by simply combining the root-coherence function and the phase function.