Shear behavior of I-section steel with circular web opening and novel reinforcement

Abstract

For reinforcement of circular web opening in I-section steel beams, half-ring plates of novel configuration were proposed considering the economy and structural performance. To verify the proposed method, cyclic loading tests were conducted for cantilever beams with a single web opening and low shear-span ratio. The test parameters were opening diameter-to-beam depth ratio and degree of reinforcement. The test results showed that the shear behavior of I-section steel was significantly affected by web opening of standard and small diameters (= 50% and 33% of the beam depth, respectively). On the other hand, properly designed ring plates strengthened the perforated beams to exhibit the plastic capacity of solid I-section, restraining the double-curvature flexural mode of web opening (i.e., the Vierendeel mechanism). The proposed ring plates were effective not only in enhancing the flexure-shear strength of the perforated beams, but also in ensuring large inelastic deformation, irrespective of design parameters. The test results, such as the overall load-displacement relationships and buckling modes, were successfully captured by finite element analysis using Abaqus. An existing analytical model for the flexure-shear interaction capacity of the circular web opening was modified to account for the proposed reinforcement method. The predictions conservatively estimated the test strengths.