Steel fibers as only reinforcement for flat slab construction – Experimental investigation and design

This paper presents the investigation on the bearing behavior of concrete flat slabs with steel fibers as only reinforcement. In a first step, experimental investigation on large-scale plates with symmetrical loading around the column is presented. The results show an absence of punching shear failure and give information on fiber distribution and orientation in steel fiber reinforced concrete (SFRC) elements with growing thickness. In general, a decreasing fiber orientation with an increasing plate height can be noticed. Furthermore, a size effect with lower tensile strength at cracked state for large scale elements in comparison to small beam specimens is shown. As bending failure occurred for all large-scale plate specimens, yield line theory is applied for both results discussion and the development of a design concept. Design abaci eventually show possible spans and slab thickness for satisfactory structural behavior at ultimate load state.