Elastic Lateral Torsional Buckling of I-Beam with Stiffener Parallel to Web

Abstract

Design of a steel beam, needs consideration of lateral torsional buckling. One of the parameters that influence lateral torsional buckling critical moment of a beam is it’s unbraced length. To increase critical moment, the beam can be laterally braced at some points between it’s support. Another attempt to increase critical moment is done by using stiffener. This paper, presents the result of a study about the influence of vertical stiffener parallel to the web of the beam. The beam is without lateral supports. The stiffeners are welded to the edge of the flanges so that at the location of the stiffener, the beam becomes a closed cross section. The method used in this study is finite element method using SAP program. The material is considered elastic, homogen and isotropic. Parametric study is performed in this study. The parameters are location of the stiffener, thickness of the stiffener and length of the stiffener. The bending moment is constant along the beam. There are several conclusions of the study. First, effectiveness of the stiffener depends on location of the stiffener. The longer the stiffener, the higher the critical moments. The higher of the length ratio, the higher the critical moments Using this kind of stiffener, the critical moments can be increased 100 %.