Effect of transverse reinforcement on the shear behavior of reinforced concrete deep beams

Reinforced concrete deep beams are safety critical members that carry heavy loads over short spans (ACI Committee 318, 2008). Design provisions in many codes can under or overestimate their shear strength, which introduces reliability concerns in practice (Kong & Evans, 1987). This study investigates how transverse reinforcement and concrete type influence the shear behavior of deep beams. Four simply supported deep beams were tested under four point loading, two made with self-compacting concrete and two with conventionally vibrated concrete, with a shear span to depth ratio of 0.75 for all beams (EFNARC, 2002; JSCE, 2005). Web reinforcement patterns were either congested, with vertical stirrups at 50 mm, or normal, with vertical stirrups at 100 mm. Key responses recorded include load deflection, diagonal cracking load, crack patterns, and ultimate load. Results show that self-compacting concrete with normal web reinforcement produced slightly higher diagonal cracking at ultimate capacities, while both concretes reached similar capacities under congested web reinforcement (Okamura & Ouchi, 2003; Choi, Kim, & Kang, 2012; Akinpelu & Adedeji, 2018). All beams failed by sudden shear compression after diagonal crack band formation. Findings endorse self-compacting concrete for deep beams where congestion and compaction challenges exist.