Performance of Steel Perforated and Partially-Encased Composite Self-Connected Beams

The self-connected partially encased composite beams may be used rather than the conventional composite beams; those are connected by the concrete passing through the web-openings of the perforated profiles which works as shear connectors. This technique minimizes the construction cost and enhances the load carrying capacity and ductility of this kind of structures better than the perforated steel beams. The presented work investigates the performance of perforated steel and partially-encased composited self-connected simply supported beams applied to three-points of loading. The effect of the openings shape and the presence of concrete on the performance of the beams are investigated by testing eight specimens of perforated steel and composite beams. The openings’ shapes of perforated steel profiles and composite beams were square, rectangular and circular. The solid steel profiles are taken as control beams in both exposed and encased specimens. The composite beam constructed using perforated steel profile with square openings was reinforced with conventional reinforcement,and setting its stirrups passing through the openings to improve the self connection. The failure modes, strain behaviours, and load-deflection curves were extensively discussed. The composite beams reinforced with perforated steel profiles exhibit higher composite performance than that reinforced with solid profiles. The concrete encasement improved the local deformation performance of the perforated steel profiles (50-300%), leading to a more ductile behaviour and a higher dissipation of energy. The square openings provide higher connectivity than other shapes due to the better arrangement of openings and presence of reinforced concrete.