Effect of reinforcement on the strength of the web opening in steel-concrete composite beam

Abstract

The steel web of the composite beam is commonly perforated for ducts and pipes passing to save the space under the beam and keep the clearance of buildings. However, this could weaken the flexural performance and the load bearing capacity of the composite beam. The published research on the flexural behavior of composite beams with reinforced web openings is limited. In this study, five full-scale composite beams with reinforced web openings were designed and loaded by three-point bending to study the influences of the type and cross-sectional area of stiffeners on the flexural performance of composite beams. For the purpose of comparison, a similar composite beam was designed without the web opening and a composite beam with the web opening was constructed without the reinforcement. As revealed from the experimental findings, the web openings reinforced with longitudinal stiffeners considerably improved the ultimate bearing capacity of the composite beams. When the cross-sectional area of the double-sided longitudinal stiffeners reached the weakened area of the steel web opening, the ultimate bearing capacity of the composite beam with reinforced web opening was comparable to the normal composite beam without web opening. The web opening reinforced with transverse stiffeners failed to significantly improve the ultimate bearing capacity of the composite beam. Moreover, the analytical models were put forward for predicting the ultimate bearing capacity of the composite beams with reinforced web openings.