Study of Flat Slabs Strengthening against Punching Shear

摘要

The paper focuses on punching shear strengthening of flat slabs. In the study, different, in practice commonly used systems of strengthening are introduced, systems used less frequently are also mentioned. Chosen methods of strengthening are modeled using FEM software considering material nonlinearity and crack development in structures. 3D models with brick finite elements and discrete modeling of reinforcement are used. The way of modeling of the structure itself is verified against known results of tests of concrete slabs under punching shear. Comparison of individual systems of strengthening is performed from the viewpoint of absolute value of punching shear resistance and it is supplemented by calculation of punching shear resistance according to design code EC 1992. Simultaneously, results are compared to the approach of Critical Shear Crack Theory that places great emphasis on deformation capacity of the slab itself, which can be easily determined from FEM models which allow for material nonlinearity.