Flexure-Shear Capacity of Perforated Steel Beams Reinforced with Novel Ring Plates

Abstract

A web opening at the end zone of an I-section steel beam decreases the load-carrying capacity of the steel member. In the present study, a reinforcement method for circular web opening was investigated, applying novel half-ring plates for better economy. To validate the structural performance of the proposed reinforcement, cyclic loading tests were performed on cantilever beams having a web opening adjacent to the plastic hinge zone. The test parameters were shear span-to-depth ratio (i.e., L/d=4.9 or 2.9), opening diameter-to-beam depth ratio (i.e., H/d=0.5 or 0.67), and ring-to-opening diameter ratio (i.e., 2R/H=1.3, 1.5, or 1.7). The test results showed that the ring plates successfully strengthened the web opening, developing a plastic hinge at the beam end. Further, irrespective of the design parameters and failure modes, the load-carrying capacity of the reinforced specimens was maintained up to large inelastic deformation. This result indicates that the plate-reinforcing method is effective for increasing both strength and deformation capacity of the perforated beams. To evaluate the flexure-shear capacity of the reinforced opening, an existing model for circular web opening without reinforcement was modified. The predicted flexure-shear interactions agreed well with the test strengths. On the basis of the test results, design considerations for the proposed reinforcement method are recommended.