Two-parameter kinematic theory for punching shear in prestressed concrete slabs Available to Purchase

According to previous investigations, prestressing has various positive influences on punching shear behaviour of reinforced-concrete slabs. While in-plane compressive stresses and decompression moments reduce the slab deformations, leading to an increased punching strength, the vertical component of inclined tendons inside the failure surface reduces the acting shear force. To allow for a realistic prediction of the punching strength of prestressed concrete slabs, these positive influences must be taken into account. In this paper, the existing two-parameter kinematic theory for punching shear in reinforced-concrete slabs without shear reinforcement is extended to consider the beneficial effects of prestressing on punching strength. The effects are investigated separately by means of punching tests with predefined edge conditions (e.g. in-plane or rotational restraint of slab edges) reported in literature. Also, the influences of arrangement and inclination of tendons on punching shear resistance are investigated. Finally, the extended theory is validated using both systematic punching test series and databank evaluations.