Author : Nasr Z. Hassan, Hala M. Ismael and Amany M. Salman

Based on the experimental result of eight hollow reinforced concrete beams, an experimental program is carried out to study behavior of the same beams but with adding 0.75% steel fiber content by volume to concrete mix. The tested hollow beams without steal fiber exhibited lower shear resistance and wider cracks when compared to solid beam. Eight beams had the same size of 2500mm x 200mm x 300mm were casted and tested under four point bending test. The results show that adding steel fibers to concrete mix optimize the mechanical properties for all hollow beams as steel fibers inhibit cracking process and increase fracture energy. All beams with steel fibers had higher load carrying capacity ranging from 3.64% to 24.73% than those without steel fiber. The inclusion of steel fibers enhanced ductility index and absorbed energy and made the reinforced concrete sections to behave in a ductile manner. ANSYS (14.5) finite element program was used to simulate the behavior of all tested beams. The steel fibers were assumed as smeared reinforcement layers embedded in SOLID65 elements. Modeling element by FE program saving time and cost.

Keywords: Steel Fiber Reinforced Concrete (SFRC), Hollow beams, PVC pipe, Finite Element Analysis (FEA), ANSYS.