Shear capacity of miniature beams with continuous staggered spiral stirrups

Abstract

Scaled-down-reinforced concrete beams with rectangular staggered continuous spiral stirrups are experimentally investigated. Scale-down RC beams were considered in the current research due to ease of construction and economic feasibility. As the brittle shear failure should be avoided, continuous research trials have been conducted to find an effective technique to improve shear failure mechanism. Twenty-two beams were investigated for shear behavior under 4-point static push-over load considering the normal stirrups and compared with continuous staggered spiral ones. Stirrup spacing, shear arm ratio a/d, and shear reinforcement configurations are the main variables. All beams were designed and scaled down to be one-eighth of the full-scale beams. To minimize the size effect of using small-scale models, mortar was used instead of conventional concrete. The focus in this study was related to improved shear capacity, dissipated energy, and shear cracks propagation. It was found that using spiral reinforcement instead of normal one leads to a significant enhancement in shear capacity and dissipated energy by 33% and 45%, respectively. Therefore, the prototype RC model expected capacities were detailed calculated considering the scale-down factor used by authors. The experimental results were compared by calculated values according to international standard and specifications.