Lateral-Torsional Buckling of Beams Elastically Restrained Against Warping at Supports

Abstract

The study presents the results of theoretical investigations into lateral torsional buckling (LTB) of bi-symmetric I-beams, elastically restrained against warping at supports. Beam loading schemes commonly used in practice are taken into account. The whole range of stiffness of the support joints, from free warping to warping fully restrained, is considered. To determine the critical moment, the energy method is used. The function of the beam twist angle is described with power polynomials that have simple physical interpretation. Computer programs written in symbolic language for numerical analysis are developed. General approximation formulas are devised.Detailed calculations are performed for beams with end-plate joints. Critical moments determined with programs and approximation formulas are compared with the results obtained by other researchers and with those produced by FEM. Very good accuracy of results is obtained.

Lateral Torsional Buckling of Steel Beams Elastically Restrained at the Support Nodes

“…In addition to the elastic restraint against rotation about the major axis of the section (i.e., in the plane of the beam greater stiffness), a restraint of warping and rotation with respect to the minor axis in the support sections is also found. Theoretical, e.g., [14,18,19,21,22,[28][29][30][31][32][33][34], and also experimental investigations [20,23,30] indicate that taking into account the actual conditions of beam support at the structure nodes can significantly affect the value of the elastic critical moment.…”

“…The problem of the beam elastic restraint at the support sections was analysed, among other, in studies [14,19,[28][29][30][32][33][34][35][36], but in most cases, they dealt exclusively with the elastic restraint against warping.…”

“…Study [34] reported the results of theoretical investigations into lateral torsional buckling of bisymmetric I-beams elastically restrained against warping at the supports. To describe the twist angle, power polynomials were employed.…”

“…It was demonstrated that "coupled" power polynomials make suitable tools for the approximation of the twist angle function of the element in those cases, in which elastic restraint against warping at support nodes occurs. Detailed analyses were carried out for the beams with end plates, however the proposed solution [34] allows taking into account any type of ribs at the end of beam.…”

Rectangular Gusset Plate Behaviour in Cold-Formed I-Type Steel Connections

“…Research focuses on investigating cold-formed structures [4][5][6][7][8][9][10] but there is a lack of connectionspecific investigation. One of the possibilities on how to improve the accuracy of steel framework analysis could be through evaluations of the actual behaviour of joints [11][12][13][14][15][16].…”