Punching Shear Strength of Steel Fiber Reinforced Concrete Slabs

The punching shear behavior of steel fiber reinforced concrete slabs was investigated in the present study. Each of 14 square slabs was simply supported along four edges and loaded to failure under a concentrated load over a square area at the center. The test parameters were the effective span to depth $a/d$ ratio, volume fraction of steel fibers ${\rho }_f$, slab thickness $h$, concrete strength $f_c^{\prime }$, and size of load‐bearing plate $r$. Test results indicate that the load‐deflection curve of slabs exhibits four distinct regions that may be characterized by first cracking, steel yielding, and ultimate load. Within the scope of the test program, an increase in the values of ${\rho }_f$, $h$, or $r$ was found to lead to an increase in both the punching shear strength and the ductility of the slab. The ultimate punching shear strength of the slabs was compared with the predictions of equations available in the literature and code equations for reinforced concrete. The British Standard CP110's equation was found to estimate the punching shear strength of the test specimens reasonably well.