Abstract
In plastic design, steel beams must be braced laterally to achieve a desired rotation capacity of plastic hinge. In this paper, necessary lateral bracing is investigated by numerical analysis. A finite element method based on the theory of thin-walled beam-shells of open cross section is used to obtain post-buckling behaviors of steel beam and the results are verified by comparison with test data. The rotation capacities of six kinds of steel beam models, which have different bending moment distribution and different lateral bracing spacing, are calculated by this method and, from these results, spacing requirement of lateral bracing to achieve a desired rotation capacity is decided using effective length factors according to bending moment gradient.
