The present paper proposes an efficient method for evaluating the elasto-plastic buckling loads of two-way single layer lattice domes under vertical loads. The connections are assumed semi-rigid as formed with screwed bolt-to-ball joints. The procedure of the method is composed of the following steps: linear buckling analysis to find the generalized slenderness ratio of the specific member that is the most relevant to their loading capacities; the generalized slenderness ratio is applied to obtain the axial strength for the specific member, based on which the elasto-plastic buckling load is evaluated. The comparison of the evaluated buckling loads with those obtained from FEM elasto-plastic buckling analyses proves that the procedure is valid and efficient enough to be applied in design practice. Based on safety factors, given in some recommendations, the allowable column strength is also proposed for proportioning the members of the single layer lattice domes.
