Shear strength of prestressed concrete beams considering bond mechanism in reinforcement

According to traditional theory, there should be shear stresses in the cracked tension zone due to the presence of bond between longitudinal tension reinforcements and surrounding concrete. To investigate the effect of this bond mechanism on shear behaviors of prestressed concrete (PSC) members with and without shear reinforcement, the dual potential capacity model (DPCM) was adopted in this study. The size effect typically observed in large PSC members was also considered in the proposed method by addressing the shear crack concentration concept. Verifications of the proposed model were conducted using the extensive shear database of PSC members with various material properties and geometrical details. As an extreme case, the perfect-slip behavior (no bond condition) between a prestressing strand and surrounding concrete in unbonded post-tensioned (UPT) concrete members was considered in the proposed model, and their analytical results were used to identify how the bond mechanism affects the shear strengths and failure modes of PSC members.