Seismic Behavior of Steel Fiber Reinforced Concrete Columns

The present paper provides an overview of recent developments in the study of the seismic behavior of Steel Fiber Reinforced Concrete (SFRC) columns. It has been shown that the combination of steel fibers reinforcement with the traditional rebars is a promising solution that leads to an efficient performance due to a complex effect between the two forms of reinforcement. However, the attractive properties performed under gravity loads and static solicitations are not sustained by an exhaustive study of the behavior under seismic loads and few results are available in the literature. The main objective of this experimental campaign is the evaluation of the cyclic behavior of SFRC for a possible use (in combination with traditional reinforcement) in seismic columns of RC frame structures. In particular, it is investigated if fibers may be added to transverse reinforcement for increasing structural ductility and for reducing the stirrup concentration in joint regions. Special attention is devoted to highlight the role of steel fibers in changing the dissipated energy, the ductility and the damage configuration. To this aim, an extensive experimental program was conveniently designed and early results will be presented. It has been proven that fibers highly reduce the damage by preventing the concrete cover to spall out and, hence, the buckling longitudinal reinforcement. The crack width of SFRC column is lower than that of the plain concrete with a reduced crack spacing, thus ensuring an optimal behavior at the Damage Limit State (DLS). Moreover, the use of fibers enhances the energy dissipation properties as well as the local and global ductility up to collapse.