Abstract: “Strengthening and rehabilitation of structures is a major concern for researchers in the civil engineering community in recent years due to the aging of these structures and the need for effective methods of strengthening. Concrete slab can be used for strengthening existing steel beams, In this research, the behavior of composite beams was studied. An experimental program was carried out to test fourteen simply supported composite beams and a Steel I-beam without any concrete slabs. The composite beams were divided into three groups to investigate the strengthening of steel I-beam with a concrete flange with variable slab thickness, slab width and variable position of top steel I-beam flange to the concrete slab. A valuable conclusion help structural engineer in design of composite sections is gained.”

Keywords: Strengthening, Concrete Slab, Steel I-beam, Shear Connectors, Composite Section.