Design wind loads for structural frames of flat long-span roofs: Gust loading factor for a structurally integrated type

The primary purpose of this study is to present simple formulae for estimating the design wind loads for the structural frames of flat long-span roofs taking account on their dynamic response of turbulent wind forces. This paper discusses the design wind loads for a structurally integrated type of roof, such as a space truss. The roof structure is supposed to act like an elastic plate under wind loadings. The first modal force acting on the roof was measured for various wind directions in two turbulent boundary layers. Based on the experimental results, the gust loading factor, defined as the ratio of the maximum peak response to the mean response in a time duration, was computed. The effects of the following parameters on the effective wind load acting on the roof structure are investigated: (i) turbulence intensity of the approaching flow, (ii) wind direction, and (iii) building geometry. An empirical formula for the gust loading factor is provided as a function of these parameters. The application of this formula to general conditions is discussed.