Experimental study of Flat Slab with Openings under Punching Shear Load

Abstract

This paper offerings a wide-ranging study to investigate the punching shear behavior of steel fiber reinforced concrete flat slab. The study involved of ten specimens tested under static load and divided into four groups; the first group included one solid slab which considered the control slab. While the remaining groups were parametric slabs strengthened with different ratios of steel fibers with openings. The used variables were use of different ratios of steel fibers (0.5, 1, 1.5, and 2) % in addition to fabrication openings with varied number, location, and shape. The results showed that the slabs behaves linearly until it reaches about average value 18% of their ultimate strength. The openings presence affected the load carrying capacity which decreased the cracking load by (55.3%) when compared with the solid slab. The displacement is the most affected property by the openings which increased by (14.4%) when compared with the solid slab. The increment in the fiber’s ratio revealed a compensation to the loss in load with gaining an average upgrade by (12%). The increase of openings number caused less displacement and decrease the ultimate strength which the strength decreased by average of (3.7%) and the displacement decreased by average of (11.3%) approximately.  The conclusion was the presence of the openings had an effect even on the percentage of upgrade in the strength as a result of the addition of steel fiber, as the presence of the openings reduced the possibility of obtaining large upgrade due to weaken the concrete member.