The behavior of high strength concrete columns; HSCC with steel fibers under cyclic loading was investigated. Fourteen half-scale column specimens were tested under cyclic lateral load. The key variables covered in this investigation include the steel fibers ratio ranging from 0.00% to 1.50%. The concrete strength varied from 50 MPa to 100 MPa. The columns were subjected to constant axial loads corresponding to target values of 10%, 25% and 45% of the column axial-load capacity. The confinement index values were 0.122, 0.230 and 0.392. The columns were designed according to seismic requirements of ACI 318 Code.
The study present that the steel fibers is shown to improve the performance and ductility of HSC columns. Column with 80% higher amounts of transverse reinforcement than that required by seismic provision of ACI 318-08 and with steel fiber content 1.5% showed ductile behavior and higher ultimate capacity. The results indicated that increasing the axial load level from 10 to 45 percent reduced the maximum displacement by 34 percent. The need to include the axial-load level in ACI Code requirements for confinement reinforcement is pointed out.
|
