Flexural behavior of RC beams with regular square or circular web openings

This paper presents a study aimed at investigating the influence of multiple web openings along the length of an RC beam on its flexural behavior. A total of nine rectangular beams were tested. Diagonal reinforcement around openings effectively prevented premature failure of some specimens due to Vierendeel action, the expected failure mode according to bending moment-axial force interaction diagrams. Longitudinal rebars and full-depth stirrups adjacent to openings and short stirrups in the chords prevented beam-type and frame-type shear failures. The length of the plastic failure mechanism increased in the presence of multiple openings compared to beams with a single opening.