Application of steel fiber reinforced-concrete in post-tensioned flat slabs: A numerical study

Despite the outstanding mechanical properties, SFRC is still underutilized in the load-bearing structures, mainly being restrained to the non-structural applications. This paper primarily investigates the effect of the innovative combination of steel fibers and the post-tensioning on the performance of concrete slabs and assesses the feasibility of using steel fiber as substitute for the conventional reinforcement in post-tensioned slabs. Building on the experimental work done by Virginia Polytechnic Institute and State University, numerical and theoretical analyses were employed to verify and extend the experimental findings. In the paper, two different reinforcement solutions (steel fibers or conventional reinforcement) were used in the slabs, and they were combined with four different tendon layouts. Among them, the banded-banded tendon coupled with steel fibers significantly enhanced the punching shear resistance of the slabs. To deepen the understanding of SFRC’s viability as a structural material, the flexural strength of the slabs obtained from nonlinear finite element analysis (NLFEA) is compared against the theoretical results of design methods outlined in fib Model Code 2010 (MC2010), new FprEC2:2022 (prEN 1992–1-1:2022(E)), IAPMO UES ER-465 (IAPMO 465), and Norwegian NB 38 (NB 38). The results indicates that some of the certain provisions in the American and European Codes might be simplified, for instance: 1) steel fibers might be used as the only reinforcement to replace the minimum required bar reinforcement in post-tensioned slabs, and 2) combination of steel fibers and banded tendon layout, which could further simplify the construction process, might be applied in the engineering construction.