The Effect of Steel Fiber Content on the Behavior of Reinforced Concrete Bubbled Slab: Experimental Investigation

Utilizing Bubbles in the slab is a revolutionary way to get rid of the concrete in the middle of a traditional slab; since this concrete serves no structural purpose and adds a lot of dead weight to the structure, using a bubble in the slab will weaken the slab and reduce its efficiency by (10%), this research presents an experimental study of steel fiber effects on bubble slabs and checks if steel fiber covers the messing efficiency and the effect on the type of failure. The program for the experiment is to test five slabs with (1760 mm × 420 mm × 125 mm) dimensions, divided into one solid slab without bubbles and steel fiber, one bubble slab without fiber, and three bubble slabs with three different fiber percentages, the experimental results shows that the three steel fiber bubble slabs (0.5%S.F.B.S, 1%S.F.B.S, 1.5%S.F.B.S) show an increase in yield load and ultimate load by (16%,20%,26.3%) for yield load and (14.5%,20.26%,25.2%) for the ultimate load respectively compared with the solid slab (S.S), and increases yield load and ultimate load by (31.8%,36.36%,40.9%) for yield load and (26.8%,33.2%, 39.8%) for ultimate load compared with bubble slab (B.S), for first crack load in solid slab (S.S) and bubble slab (B.S) first crack appeared at (13kN, 11kN) and for steel fiber bubble slabs (0.5%S.F.B.S, 1%S.F.B.S, 1.5%S.F.B.S) first crack appeared at (18 kN, 22 kN, 24 kN) respectively and change of type of failure from brittle sudden shear failure for the bubble slabs to ductile flexural failure.