Experimental Evaluation of the Load Carrying Capacity of SFRC Flat Slabs Varying the Rectangularity Index of Columns

This work aims to evaluate the punching shear carrying capacity of flat slabs of reinforced concrete added with different amounts of steel fibers and varying the rectangularity index of columns under symmetrical loading. The addition of steel fiber provide higher load-carrying capacity. However, the column rectangularity index tends to lower that load-carrying capacity for magnitudes beyond 1.5 for the tested slabs. Nine models were tested with dimensions of 1,800 x 1,800 mm and 130 mm height varying the amount of added fiber (0, 50 and 60 kg/m) and the index of rectangularity (1.0, 1.5 e 2.0). From the results, the load carrying capacity, the vertical displacement, and the crack patterns were obtained. In addition, the results were compared with other similar studies and analytical models for steel fiber. The addition of steel fibers showed to be effective in increasing the punching shear load carrying capacity, it leads to a higher number of cracks and higher vertical displacements. Regarding the rectangularity index, for those tested slabs which was below 1.5, the load carrying capacity of punching shear of the slabs increases. However, for slabs above 1.5, it was observed that the punching shear load carrying capacity decreases.