Influence of concrete slabs on lateral torsional buckling of steel beams

摘要

The use of pre-cast concrete floor slabs in steel framed structures is quite common. A non-connected concrete slab on top of a beam will provide some restraint to the beam. It may even be that the restraint provided by the floor slab prevents lateral torsional buckling. To investigate the restraining effect of a concrete slab on the top flange of a steel beam subject to lateral torsional buckling, two experimental load tests were performed. The first test is a test where a steel beam with lateral restraints at the supports only (fork conditions), was loaded in four point bending. In a second test, a single 1.2 m wide non-connected concrete slab was placed on a strip of rubber at mid span of the steel beam. The tests were carried out on 7.2 m long IPE240, S235 beams subject to the same loading conditions. The test results have been compared with results obtained from Finite Element simulations and theoretical analyses.