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Lateral torsional buckling of open cross-sections with lateral and torsional restraints

Lateral-torsional buckling (LBA) resistance often governs the design of open-section beams. It can be greatly increased by taking into account restraints provided by a floor or a roof, typically a sandwich panel. LBA resistance is compared on IPE-section and cold-formed C-section.

Concrete floor, if connected to beams by shear studs, effectively restrains lateral-torsional buckling of these beams. Trapezoidal sheeting or sandwich panels typically connected by self-drilling screws do not have sufficient strength and stiffness to restrain lateral-torsional buckling completely. But they may help up to some point. How this lateral-torsional restraint is applied is described in this article.

In this thorough study by authors from ETH, Zürich, the results of three software of linear buckling analysis are compared: LTBeam, Abaqus, and IDEA StatiCa Member. The differences are discussed and explained. Furthermore, the results of geometrically and materially nonlinear analysis with imperfections of two software are compared: Abaqus and IDEA StatiCa Member. LTBeam does not have this functionality.

Two cross-sections are investigated:

IPE 240
CFC265x65

Three types of restraints at the top flange are investigated:

Lateral torsional buckling of open cross-sections with lateral and torsional restraints

Conclusions