Influence of Flange Breadth on the Effective Width of Composite Beams

A composite beam is made up of a reinforced concrete slab connected to a steel beam by means of shear connectors. If the slab was wide and the composite beam is under positive bending moment, it is evident that the simple beam theory does not strictly apply because the longitudinal stress in the concrete flange will vary with distance from the beam web, the flange being more highly stressed over the web than in the extremities. In this paper a threedimensional linear finite element analysis, using ANSYS program, is done to study the effect of the breadth of the slab on the effective slab width and stress distribution across the slab width (shear lag) of composite steel-concrete beams. The stresses of concrete and steel are compared with stresses obtained from T-beam theory for variable breadths of concrete slab. Effective width for composite beams with different breadth under various loads has been drawn.