Design And Study On The Stability Of The Single-layer Reticulated Shell Structure Under Non-uniform Snow Loads

The stability of single-layer reticulated shell structure is a focusof research of the spatial structures. For large span reticulated shellstructures, the instability often occurs before structural strengthdamage, and therefore the control factors of design for this type ofstructure is not determined by the strength of material but by thestability performance of the structure. And this makes the stability ofsingle layer reticulated shells attracts more attention of researchers.The collapse of spatial structures shows that the stability performanceof reticulated shell structure is sensitive to non-uniform distributedsnow loads. Up to now, a lot of researches on the stability of reticulatedshell under uniform loads have been done, but the influence of non-uniformsnow loads has rarely been studied.This paper studies the influence of non-uniform snow loads to thestability of reticulated shell structures. Based on the finite elementmethods and using the software MST, a Kiewitt type single layerreticulated shell is designed, and then using the software ANSYS, thenonlinear stability analysis of the single layer reticulated shell iscarried out. By the comparison of the pre and post-buckling curves thestructure, a better understanding of the influence for the differentdistributed sow loads to the stability performance is reached, and thestability capacity of the structure is determined.In the studies of this paper, to the stability of single layerreticulated shell structure, not only the influence of non-uniformdistributed snow loads on the base surface of the structure is considered, but also the influence of non-uniform distributed snow loads in the radialdirection of the structure is considered. The analysis results show thatwhen the non-uniform distributed snow loads are applied on the two outerrings of the half span of the structure, the stability capacity is theminimum. Comparing with the stability capacity when the uniform snow loadsis applied on the whole and half span structure respectively, this valuedecreases by36.4%and22.3%. Comparing the uniform distributed snow loads,when the non-uniform distributed snow loads in radial direction areapplied on the whole structure, the half span structure and the two outerrings of the structure respectively, the stability capacity decreases by29.6%，10.3%and5.1%. This shows that the character of the non-uniformdistribution of snow loads in the radial direction of the reticulatedshell structure has much influence on the stability performance of thestructure. Under the combination of the dead loads and the differentdistributed snow loads, the minimum stability safety coefficient of theK8type reticulated shell designed by this paper is5.48. This safetycoefficient is larger than the needed coefficient by code, and shows thestructure designed in this paper is safety enough.