Experimental study of shear behavior of high strength steel fiber reinforced concrete columns

The ties configuration in accordance with every requirement of ACI 318-14 or newer for confinement and shear strength in a reinforced concrete (RC) column is strong required so that the RC column can dissipate seismic energy through flexural mechanism. In addition, according to ACI 318, the amount of confinement may increase as axial loading level increases. The increase of amount of confinement may lead to construction difficulties, particularly in column with small cross-section size; meanwhile, according to ACI 318, there is an upper limit for the transverse reinforcement in an RC column. An alternative material that has feasibility in substituting and reducing the traditional transverse reinforcement while maintaining shear strength and ductility is required. Application of short and discontinuous steel fibers to concrete element can be an alternative, since previous experimental results showed the improvement of shear strength, ductility, and toughness after adding steel fibers. However, no comprehensive experimental study of shear behavior of steel fiber reinforced concrete (SFRC) column with high strength concrete and steel reinforcing bars under different axial compression ratios subjected to lateral displacement reversals were available. In this study, large-scale double curvature SFRC columns with concrete strength design, yield strength for longitudinal reinforcement, and yield strength for transverse reinforcement, respectively of 70 MPa, 685 MPa (SD685), and 785 MPa (SD785) were prepared and tested.