Ductility Enhancement of High Strength RC Columns Using Steel Fiber Reinforced Concrete (SFRC)

Abstract

The principal aim of this research is to improve the seismic performance of high strength concrete (HSC) reinforced columns using fiber reinforced concrete (FRC) by mixing steel fiber into the concrete. Two reinforced concrete columns 200mm x 300mm in cross-section with a height of 1250 mm were tested under cyclic lateral loading. The first specimen was casted using high strength concrete of 100 MPa and the second specimens were also casted using similar concrete strength but the steel fiber of 0.5% by volume was added to the concrete in the plastic hinge region. Both columns were subjected to lateral cyclic load until the failure occurs. The test results showed that the use of FRC in the plastic hinge region could significantly improve column displacement ductility. The maximum drift at column failure at 4.5% for non-ductile column could increase to 8% in FRC column. It is evident that the cracks in FRC column are much smaller properly spread in the plastic hinge region and hence the plastic hinge could be able to rotate without lateral strength being compromised. In FRC column, concrete spalling was observed in a very high drift (7%) and bar buckling occurred at around 8% drift whilst in HSC column concrete spalling and bar buckling occurred at only 3.5% and 4% drift respectively. It was evident that the use of steel fiber in HSC columns could significantly improve seismic performance of the column.