A New Method for Wind-Induced Response Analysis of Long Span Roofs

Long span roofs are usually characterised by their dense distribution of natural frequencies and remarkable coupling effects among different natural modes. Those traditional methods, such as modal superposition method, are not suitable for analyzing wind-induced response of these structures. In this paper, a new method named as Ritz-POD method is proposed to analyse wind-induced response of long span roofs in frequency domain, which synthesises proper orthogonal decomposition (POD) technique and direct superposition method with Ritz vectors. The eigenvectors of fluctuating wind load with POD technique are regarded as spatial distributions of this load to generate Ritz vectors, and wind-induced response is analysed by direct superposition method with Ritz vectors. Therefore, it can take into account multimode buffeting response automatically, even the case that structures vibrate in high order modes. According to this method, the wind-induced response of a single layer reticular shell is analysed, and compared to the results achieved with modal superposition method. It shows that Ritz-POD method is more accurate and efficient with fewer Ritz vectors.