Effective Strength of 'Square‐and‐Diagnonal' Double‐Layer Grid

The effective strength of “square‐and‐diagonal” double‐layer grids constructed by a bolted jointing system is derived in this paper; and is defined as the strength represented in terms of the stress resultants in a continuum plate and determined by periodic modes of elastic buckling under a uniform stress state without an overall buckling deformation. The effective bending strength of the grid is derived under the equivalent stress state $M^{11}=M^{22};$ $M^{12}=M^{21}=0\text{,}$ which is the only stress state for the pin‐jointed case. Because of the existence of joints sizes and connecting rigidities in actual nodes, the effect of them on the effective strength is quantitatively investigated. The effect of web members on the effective strength is also investigated. Furthermore, the effective strength is compared with the strength estimated from the elastic buckling load obtained by a discrete element method for numerical examples.