Shear Strength of NSC and HPC Beams with Stirrups

Theanalysisofshearstrengthofonlylongitudinallyreinforcedconcretebeams,inwhichaconstant shear force acts throughout the shear span, has led to a shear strength formula predicting the experimental behavior in a more accurate and uniform way than other Codes or authors expressions. On the basis of the shear strength expression found for beams without stirrups, a formula able to predict the shear strength of NSC and HSC beams with transverse reinforcement is here proposed. The shear strength expression of a beam with transverse reinforcement is obtained by adding the resisting contribution provided by concrete to that provided by stirrups. The shear strength contribution due to stirrups inclusion takes into account not only the truss mechanism, but also the interaction between the truss action and the beam action. The mutual influence of the truss action on beam and arch strength contribution is here considered. For this reason a formula for beams with stirrups which differs from that used for calculating the shear strength of beams without transverse reinforcement is here proposed. The reliability of this formula has been verified using several test data and results found in the literature. The here provided expression has found to predict the experimental shear behavior in a more accurate and uniform way than other Codes formulas or analytical expressions recently proposed by other authors.