Cold-formed steel sections are widely used in construction work as its low cost. This
paper presents a series of bending tests, to examine the influence of encasing cold-formed steel
(U-section) in a reinforced concrete beam on the beams capacities, mode of failure and ductility.
The cold-formed steel section breadth, height, and length are the main parameters studied and
presented. Eight full-scale encased composite beams have tested under lateral loading up to
failure, in addition, to one full-scale reinforced concrete beam (without cold-formed steel
sections). The experimental results have recorded and monitored to clarify the influence of the
studied parameters on the composite beam behavior. The experimental results have compared
with the reference beam. It has found that the cold-formed steel (U-section) increased the beam
load carrying capacity and improved the beam ductility. It has observed that encasing the formed
steel sections reduced the influence of the steel sections local buckling