Simple Method to Stabilize I‐Beams against Lateral Buckling

Abstract

Lateral restrained and free buckling of I‐beams often represent a limiting factor in their bending performance. Consideration of this becomes increasingly more important when the engineer seeks full advantage of new thermomechanically rolled high‐yield‐strength steels. The writers present a solution to this problem consisting of warping‐preventing devices in form of U‐sections connected to the web and flanges of the I‐section. General expressions based on Fourier expansion of the displacements, enabling the determination of the elastic critical loads given the characteristics of the stiffeners (i.e., number, stiffness, and position along the axis of the I profile) are developed. Typical examples illustrate that the proposed stiffeners are very efficient, in particular if they are placed near their optimum position. Therefore the same examples show the efficiency of the stiffeners as a function of their position. Just one or two stiffeners near their optimum positions increases the elastic critical stress by a multiplier in the range 2 to 4.