Lateral-Torsional Buckling Behaviour of Triangularly Corrugated Web Beam

Abstract

Lateral torsional buckling (LTB) is a common failure mode of large span beams. In this phenomenon, the beam becomes unstable along the unbraced length. This instability of beams can be identified by out-of-plane deflection and twisting. In this paper LTB strength of triangularly corrugated web beams under bending condition is investigated. Examined steel beams consist of two flanges and a thin triangularly corrugated web, connected by automatic welding. In the literature, the LTB strength problem of steel beams was dealt with mostly for steel beams with plate, sinusoidal and trapezoidal corrugated webs. Researches of the LTB behaviour of beams with triangularly corrugated webs were found out to be very limited. A parametric study is carried out for various beam spans and corrugation densities. A general-purpose finite element program (ABAQUS) was used. The corrugation densities adopted in this study represent practical geometries, which are common used for such structures in building practice. Plot showing the influence of compressed flange slenderness on value of reduction factor for LTB is presented. It is determined that existing buckling curves poorly describe the change of reduction factor depending on slenderness of compressed flange for triangularly corrugated web beams. Finally, recommendations were proposed for the design of simple supported steel beams with corrugated webs against lateral torsional buckling in accordance with numerical results.