EFFECT OF COMPOSITE ACTION OF CONCRETE SLAB ON UNSYMMETRICAL STEEL PLATE GIRDER UNDER COMBINED BENDING AND TORSION MOMENTS

Abstract

In general, the reinforced concrete slab in composite unsymmetrical steel plate girder contributes in increased the ultimate strength of composite section under combined effect of bending and torsion moments. The contribution value of slab in composite section is unknown, so this study is adopted. Six specimens were either non-composite or composite reinforced concrete slab and with symmetrical/unsymmetrical steel plate girders were adopted in this study. The specimens were divided into three non-composite steel plate girders and the others were composite with RC slab. The specimens were tested under effect of combined bending and torsion moments.The general behavior and response of the tested specimens were recorded and discussed in this paper. For each tested plate girder, the ultimate strength, load at cracking, failure's mode, and load/deflection relationship at mid-span and under points load were gaged. The experimental results show that the concrete slab contributes in increasing the ultimate load of composite section by a ratio (53.85)% for symmetrical section and (155.63 – 242.51)% for unsymmetrical section when the composite girder under loaded out of supported plane, and the contribution value of concrete slab in composite plate girder increased in unsymmetrical section than symmetrical section this is due to the ideal use of materials.