Abstract
In this paper, for the lateral-torsional instability of beams between cross members, the following investigations are carried out;
(1) The basic strength curves of rolled and welded laterally unsupported beams with initial clockedness and residual stresses are obtained by using the FEM analysis.
(2) A formula on the ultimate strength of elastically restrained beams at both ends is developed with concerning the basic strength of beams.
(3) The strength of the isolated beam models restrained by intermediate descrete supports are parametrically analized.
(4) The restraining effects of the adjecent members and bracing systems on the lateral buckling strength are investigated more precisely by the FEM analysis. And the practical formulae obtained by modifying Nethercot-Trahair method based on the elastic buckling theory are proposed.
