Study On The Influence Of Non - Uniform Distributed Snow Load On The Safety Of Portal Frame

Snow disasters occur frequently at home and abroad, which poses a serious threat either to people’s lives and property or building security. Every time snowstorm disaster occurs could cause serious damage to the light portal frame structure as a result of it was a structure sensitive to wind and snow loads. It shows that the reason that cause structural damage or collapse is the improper snow load values in calculate as well as the structural design can not grasp the snow distribution pattern. Thus, it is particularly important to determine the real value and snow distribution pattern by conducting actual research. But generally speaking the situation of snow loads studies our country is still austere especially in areas related to uneven snow loads on structural safety study. Under such a background, taking snow characteristics and typical roof snow distribution pattern as a research, through the analysis on the door frame structure by suing finite element software.this paper analyzes the follow factors:Firstly, snow density on the roof and the ground was investigated by using Snow Fork and small weather station, the main factors which affects snow characteristics was determined by analyzing how air temperature, air humidity and now thickness act on snow density.Secondly, in order to more intuitive observation the snow distribution patterns, the face of the house with a parapet snow distribution patterns were observed. It was found by observation that snow distribution patterns mainly influenced by the wind direction and speed. Maximum snow thickness is present to 2.5 times of the parapet. The model of single-span gable roof, double cross gable roof, arched roof were established to obtained the snow distribution pattern, it came to a conclusion that distribution pattern in windward side well distributed while the leeward area is more complex.Thirdly, single Pin portal frame structure finite element model was established to analysis static and stability of portal frame. Analysis how slope affects the of shear bottom of the column, capitals across the vertical displacement and horizontal displacement under the whole cross-slope roof snow load, 1/2 across snow load, and under 1/4 snow load. Meanwhile, investigated how the factors such as roof slope, the initial defect structure, cross-sectional component effects the structural stability.