Wind-sensitivity And Equivalent Static Wind Loads Of Spherical Shells

With the development of long-span, light weight and low damping structures, wind-sensitivity of modern structures becomes prominent. Recently, the wind-resistant design method of high-rise structures, towers and bridges has been forming basically, but the design method of long-span roofs is not ripen, owing to the influence of the muti-load pattern, muti-modality and muti-equivalent goal of the structures. It is not able to meet the requirements of the security and the efficiency that the wind-resistant design method of high-rise structures is adopted in the wind-resistant design of long-span structures. In this paper the wind-sensitivity theory is ameliorated and the wind-sensitivity of the spherical shells is studied based on the conception of the wind-sensitivity point. The research is focused on the classification of the wind-resistant design of the spherical shells and the equivalent static wind loads of different grades of structures. In addition, the analyses of wind-sensitivity of super large-span spherical shells is concerned in the paper.The main work of this paper is as follows:(1) In the wind-sensitivity theory, the resonance effect coefficient is used to analyze the frequency effect and modal effect because of the muti-modality of the spherical shells.(2) The relation equations between the wind-sensitivity points and the principal influence factors are obtained by comparing the dynamic responses different single/double layer spherical shells with different parameters. Based on the classification of the wind-sensitivity points, some single layer spherical shells are low-wind-sensitive structures as a result of their low height-span ratios, other single layer spherical shells are wind-sensitive structures as a result of their high height-span ratios, double layers spherical shells are low-wind-sensitive structures.(3) The equivalent static wind loads are obtained on the basis of the wind-induced vibration coefficient from fitting.The mean wind load is used in the linear fitting of the extremum response as the primer vector. The joint displacement and the truss stress is analysised for statistic in order to gain the wind-induced vibration coefficient of spherical shells and its scope in engineering applications.(4) From the analysis of elastic time history, the modes, the joint displacements, the internal forces in the trusses and the support reactions of a number of super large-span spherical shells with three kinds of spans are obtained. The fluctuating responses are low enough to be ignored and the super large-span spherical shells are low-wind-sensitive structures.