ABSTRACT
The stability of beams subject to lateral torsional buckling can be significantly improved by local torsional restraints of the flanges. If no stiffeners are inserted between the flanges, web distortions can reduce the restraining effect considerably. In the presented paper, the influence of local flange restraints on the stability of beams is described in detail. In addition, calculation models to determine the torsional spring stiffness and the influence of the local buckling effect are treated. The determination of the critical buckling moments and the description of load capacity tests of beams with local torsional restraints follow. From the statistical evaluation of the results from load bearing tests on I-beams with local restraints of the top chords a design approach based on EN 1993-1-1 is presented.
