The effect of hybrid fiber and shear stud on the punching performance of flat-slab systems

Abstract

In this paper, for the first time, the binary/ternary hybrid fiber and/or shear stud reinforcement as a measure was used to improve the punching performance of flat-slab systems by innovative self-compacting concrete (SCC). Because in these slab systems, sudden and brittle punching failure can be seen due to application and design errors, early removal of formwork, changes in the purpose of use of the building, earthquakes, etc. Besides, numerous studies investigated the punching performance of the single fiber and/or shear stud reinforced flat-slab systems, but research into the measures of the hybrid fiber or the combined use of hybrid fiber and shear stud reinforcement, which were the variable parameters of this study, was quite lacking. For this purpose, the half-scale slab-column connection elements were produced from SCC containing different punching measures (binary/ternary hybrid and/or shear stud) and tested to investigate the punching performance of flat-slab systems. In conclusion, it was found that hybrid fiber reinforcement was the best punching measure to improve the punching performance of slab-column connection elements with/out shear stud. Besides, 3D graphs were drawn so that designers and researchers could estimate the punching strength and energy absorption capacity for flat-slab systems with/out shear stud based on the parameters of micro fiber type and total volume fraction. On the other hand, empirical formulas were developed to predict the punching strength of binary/ternary hybrid fiber reinforced flat-slab systems with/out shear stud by compressive strength, fiber reinforcement index, the slab useful height, and the punching perimeter parameters.