Web Openings in Composite Beams with Ribbed Slabs

Fifteen tests to failure are performed on full-scale composite beams with web openings. The beams have ribbed slabs that use formed deck steel. The ribs are perpendicular or parallel to the steel section. The effects of moment-shear ratio, quantity, and placement of shear connectors, deck orientation, and deck thickness are studied. The concrete slab contributes significantly to both the flexural and shear strength of beams at web openings. Peak loads are governed by failure of the slab. Rib failure around shear connectors occurs in slabs with transverse ribs, while longitudinal shear failure occurs in slabs with longitudinal ribs. Strength at an opening increases as the shear-connector capacity above the opening and between the opening and the support increases. The implications for design are discussed.