Seismic Performance Enhancement of Non-Ductile RC Columns Using Steel Fiber Reinforced Concrete (SFRC)

The principal aim of this research is to improve the seismic performance of non-ductile 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 normal strength concrete of 24 MPa and the second specimens were also casted using similar concrete with similar strength but the steel fiber of 1% was added to the concrete in the plastic hinge region. The axial load for all specimens was 300 kN and kept constant during the test. The test results showed that the use of FRC in the plastic hinge region could significantly improve column displacement ductility. The maximum drift at lateral strength loss at 3.7% for non-ductile column could increase to 6% in FRC column. It is evident that the cracks in FRC column are much smaller and more widely 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 (5%) and bar buckling occurred at around 6% drift whilst in non-ductile column concrete spalling and bar buckling occurred at 2.5% and 3% drift respectively. It was evident that the use of steel fiber in non-ductile columns could significantly improve seismic performance of the column.