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Punching tests on continuous concrete slabs are very expensive and elaborate. As a consequence, the majority of the existing punching tests have been performed on isolated specimens representing only the hogging moment region around the considered slab–column connection. Isolated punching tests are valuable in order to analyse the punching shear behaviour systematically. Nevertheless, beneficial effects of slabs' continuity (e.g. moment redistributions and membrane actions) may not occur in these tests. To investigate the punching shear behaviour of continuous concrete slabs, in this paper the existing two-parameter kinematic theory for punching shear in reinforced and prestressed concrete slabs is applied. The beneficial effects of slab continuity on punching strength are estimated based on a theoretical model described in the literature. The kinematic theory is applied to evaluate punching tests on a continuous slab, revealing good agreement between predictions and experimental results. As only few punching tests on continuous slabs are available, further parametric studies are performed to analyse the effects of slab continuity on punching strength in more detail. The results suggest higher punching shear capacities for continuous slabs than for isolated slabs. Nevertheless, the beneficial influences of slab continuity on punching strength strongly depend on the slab stiffness and flexural cracking. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]