Grid-purlin system composed of RHS members are known to be effective to prevent buckling of the welded beams. In this paper, the bracing rigidity of triangulation isogrid purlin is evaluated and lattice cylindrical shell composed of arcuate beams and welded grid purlins are studied. The linear, elastic, and elasto-plastic buckling strength of the roof are analyzed using FEM analyses. Their results are compared with the shell theory with continuum analogy and easy design approaches are investigated.
