Buckling and reliability analysis of single layer grid dome with diagonal brace under snow load

The present paper aims at investigating the buckling strength and its reliability of a two-way single layer grid dome stiffened by diagonal braces under uniform and non-uniform snow loads. The dome is supported by a substructure which is composed of a set of four enclosed eaves as a tension ring and a two-story frame underneath. The eaves, looking circular if projected on a plan, are arranged around the dome in order not to raise too much tensile stresses into the diagonal braces in the dome. First, characteristics of linear buckling, elastic buckling and elasto-plastic buckling are investigated with emphasis on the effectiveness of diagonal braces to increase the buckling strength. Secondly, with relation to reliability analysis, the elastoplastic buckling load, defining the ultimate strength, is investigated considering the stochastic properties of steel members. The mean value and coefficient of variation of the ultimate strength are evaluated based on the stochastic properties and geometric imperfections. Thirdly, a formulation is presented to analyze the reliability of ultimate strength, then followed by its numerical analysis. Finally, based on the results the relationship between the reliability index and a global load factor is discussed in detail, revealing thereby the ratio of safety. Copyright © 2017 by Shiro Kato and Takayuki Iwamoto.