In this paper, the punching behavior of square simply supported reinforced concrete flat slabs
was experimentally and numerically investigated. Four models of reinforced concrete flat slabs were
constructed and tested. The test variables were type of concrete and load (four models): High Strength
Concrete flat slabs under monotonic load or repeated load (two models) and Normal Strength
Concrete flat slabs under monotonic load or repeated load (two models). The results showed that the
punching shear strength of flat slab models increased up to 60% with the use of HSC. While, repeated
load reduces the punching shear strength of flat slab models by about (34.4%-10%); it depends on the
level of loading, number of cycles and type of concrete. Three-dimensional (3D) nonlinear finite
element (NFE) analysis has been carried out to conduct the numerical investigation of the general
behavior of HSC and NSC flat slab models. The ABAQUS model succeeded to an acceptable degree in
predicting the structural behavior of the analyzed flat slabs with average of differences of about 5%
between the predicted and experimental ultimate load.