The Design Of Single-layer Cylindrical Reticulated Shell And Study On The Most Unfavorable Snow Load Distribution

The large-span spatial structure collapse examples world widely show that the snow load, especially non-uniform snow load is an important influence factor which leads to the instability of reticulated shell structure. The static and dynamic stability behavior of reticulated shell structures has already got extensively studied. But the research on stability of reticulated shell structure under non-uniform snow load is rare founded so far. Then the nonlinear stability analysis of the single layer cylindrical reticulated shell structure under snow loads is investigated using the finite element analysis software ANSYS. In the numerical analysis, six different snow load distributions are considered. Through the comparison of the pre- and post-buckling process and the buckling loads of the structure, the most unfavorable snow load distribution of the single layer cylindrical reticulated shell structure is founded, and some suggestions on the stability analysis of this kind of structures have been presented.Analysis results show that when the non-uniform snow loads are distributed on the middle part of half span of the single layer cylindrical reticulated shell structure, the stability behavior of the structure is the worst, and the ultimate load capacity of stability is the minimum. The structure exhibits more sudden collapse behavior comparatively. The ultimate load capacity of stability decreases by 73.76% comparing with that of the uniform snow loads acting on the whole structure. And also the ultimate load capacity decreases by 21.4% comparing with the non-uniform snow loads acting on the half span of the structure. When the snow loads acting on the whole structure, comparing with that of the uniform distributed snow loads, the ultimate load capacity of stability decreases by 31.1% due to the non-uniform distribution of snow loads. In the condition of snow loads acting on half span of the structure, comparing with that of the uniform distribution of snow loads, the ultimate load capacity of stability of the structure decreases by 17.9% due to the non-uniform distribution of snow loads. The distribution area of snow loads also has significant influence to the stability behavior of the single layer cylindrical reticulated shell structure. When the same uniform snow loads act on half span and whole span of the structure respectively, the half span snow loads will cause that the ultimate load capacity of stability decreases by 59.3% comparing with that of whole span snow loads. And also when the same non-uniform snow loads act on half span and whole span of the structure respectively, the half span snow loads will cause that the ultimate load capacity of stability decreases by 51.6% comparing with that of whole span snow loads. This shows that the non-uniform distribution of snow loads is more unfavorable than the uniform distribution of snow loads, and also for the same snow load distribution in depth, the acting location of half span is more unfavorable than that of the whole span.Based on the results of the analysis, this paper suggest that in the analysis of cylinder single-layer reticulated shell, in addition to the distribution of snow loads specified by the code, the non-uniform distribution of snow loads, especially the half span of non-uniform snow loads should be considered. For some important and large span cylinder single-layer reticulated shell structures, the condition of non-uniform snow loads acting on the middle part of half span should be considered due to the complex of the distribution and accumulation of snow.