Experimental Behavior of GFRP Bar–Reinforced CFRP Strip Tie–Confined Normal-Strength Concrete Columns under Different Loading Conditions.

In this study, a total of 10 steel and glass fiber–reinforced polymer (GFRP) bar–reinforced normal strength concrete (NSC) specimens with a square cross section of 200 mm × 200 mm were experimentally tested up to failure under different loading conditions. Out of the 10 specimens, 8 specimens had a height of 800 mm and were tested as columns under concentric and eccentric axial loads. The remaining two specimens had a length of 1,500 mm and were tested as beams under four-point bending. The tested specimens were utilized to investigate the efficiency of carbon fiber–reinforced polymer (CFRP) strip ties (CSTs) in transversely confining NSC specimens. Two configurations of CSTs were used: a square (S) configuration and a square overlapping square (SS) configuration. The experimental results indicated that the peak axial load and ductility of the concentrically loaded GFRP bar–reinforced concrete specimens were lower than those of steel bar–reinforced specimens. The peak axial load and ductility of the concentrically loaded GFRP bar–reinforced concrete specimens with SS configuration were about 49% and 100%, respectively, higher than those of GFRP bar–reinforced concrete specimens with S configuration. Also, the GFRP bar–reinforced concrete specimens tested under eccentric loading and four-point bending achieved higher peak axial loads, flexural loads, and bending moments at the second peak loads than the corresponding steel bar–reinforced specimens. [ABSTRACT FROM AUTHOR]