Effects Of Supporting Condition And Terrain Category On Equivalent Static Wind Load Of Cylindrical And Saddle-shaped Roofs

cylindrical latticed shells and saddle latticed shells are two typical kinds of span roof structures that are widely used in engineering applications. But the structures are strong sensitive to the wind loads. In the Current specifications of GB.50009-2012, wind-resistant design provisions mainly give the method suitable for these structures considering only the first vibration modes, such as tall buildings and high-rise towers, rather than long span roofs. At present our group has made some research on equivalent static wind load aimed at these two types of structures, however, the structural supporting condition and landform impact are not considered comprehensively.This paper developed the existing research by changing the parameters of wind load and structural design within the range commonly used in engineering, studying the wind-induced response and equivalent static wind loads of cylindrical steel shells with supports along four edges as well as the effect of different wind fields on wind-induced response and equivalent static wind load for saddle latticed shells, giving a way that is applied to structural design reference to determine the equivalent static wind load. The main work in this paper includes:(1) Structural design and dynamic analysis on four-edge supporting cylindrical latticed shells and saddle latticed shells were accomplished. Models of cylindrical latticed shells and saddle latticed shells were built. With the structural parameters covering the scope commonly used in engineering, modal analysis for all structures were carried out. And the influence of changing these parameters was studied.(2) Wind-induced response of cylindrical and saddle latticed shells was studied. This paper made a systematic analysis about the distribution law of structural background response and resonant response and the participation degree of various vibration modes in dynamic response under different structural parameters condition, and the dynamic response of several typical structures under all wind directions is also investigated, thus finding unfavorable wind directions. Results show that there is significant difference between the worst wind direction of wind pressure and structural wind-induced response for these two types of structures. Finally the unfavorable wind direction of wind-induced response for them was identified.(3) A parametric study is conducted to investigate the equivalent static wind loads of single-layer cylindrical steel shells with supports along four edges. The formula of equivalent wind pressure coefficients applied conveniently to engineering was obtained after considering the impact of different wind loads parameters and structural parameters on multi-objective equivalent static wind load and the convenience of engineering applications.(4) The effect of different exposure types of wind fields on equivalent static wind load of saddle latticed shells was studied. The effect of different wind fields given in GB.50009-2012 on wind-induced response and equivalent static wind load for this kind of structure was analyzed. Then a formula of equivalent static wind load based on B wind field and conversion coefficients for other types of wind fields were given.