Experimental study on the behavior of SFRC columns under seismic loads

The use of Steel Fiber Reinforced Concrete (SFRC) in columns was experimentally evaluated with the aim of reducing the stirrups spacing without compromising the columns seismic behavior in terms of drift capacity and dissipation energy. Results from eight RC columns and eight SFRC ones are reported. The columns were reinforced with hooked steel fibers with a volume fraction of 1.0%, subjected to earthquake-induced displacement reversals and constant axial loads. The spacing and the diameter of the stirrups were varied in order to verify their influence, moreover mono-axial and bi-axial quasi-static tests were performed by keeping constant the vertical load. The tests results confirmed that SFRC can reliably reduce the damage by preventing the concrete cover to spall out at earlier stages and increase the initial stiffness and the energy dissipation of the columns, especially for mono-axial loads that resulted a less severe load condition with respect to the bi-axial one. Nevertheless, it seems that, despite the fibers addition, the increased spacing reduces the columns ductility.