Efficient use of steel fiber in high-strength reinforced concrete columns

The inclusion of steel fibers has been widely used in column members due to its effectiveness in enhancing strength, ductility, and delaying concrete cover spalling failure. Reinforced concrete columns are recently included steel fibers to enhance their structural performance and control the strain in concrete. In this study, partially-fibered and fully-fibered high-strength concrete (HSC) columns were investigated and compared to non-fibered HSC columns. The partially-fibered columns were examined here to eliminate the extra use of steel fibers through the confined core of the columns. The experimental work included different study parameters: percentage of steel fiber content, columns' length, and internal reinforcement details. The columns were tested under concentric axial loads. The results were analyzed in terms of improvement in the ultimate load, displacement ductility, and energy absorption. The test results determined the impact of using steel fibers in enhancing the axial ultimate load capacities of HSC columns between 14% to 80% of that in non-fibered columns and controlling the concrete cover spalling failure. As well, the test results showed that the increase in steel fiber content improved both the ductility displacement index by 29% to 66% of that in the non-fibered column and the energy absorption index by 1.5 to 3.2 of that in the non-fibered column.