Effect of GFRP Wraps on HSC Columns Strengthened with GFRP with Different Steel Ratio

Dr. Eiad Hafiz. Zahran

Experimental investigation was conducted to study the pure compression and ductility behavior of high-strength concrete (HSC) columns strengthened with glass fiber reinforced polymers (GFRP) having different stirrup spacing and different main steel ratio. A total of twenty four columns were tested. The variables of this research are spacing of main stirrups, percentage of main steel and number of layers of (GFRP). The experimental program includes testing of two main groups (G1 and G2). Group G1 consists of three groups of columns (H1,H2 and H3), each group consists of four columns (medium scale specimens), all specimens with overall length 1200mm, columns are square with a dimensional 120 mm and main steel (4Ø6).The considered parameters were the number of layers (1-without layer, 2-one layer, 3-two layers). Variable stirrup spacing, the spacing of stirrup reinforcement was [1) without stirrups, 2) 500 mm, 3) 300 mm, 4) and 200 mm]. Group G2 consists of three groups of RC columns (C1, C2 and C3), and each group consists of four RC columns with spacing between stirrups are 200mm. the main variable between each group is number of layer (without layer, one layer, two layers). For columns each group consists of variable ratio of main steel, the ratio of longitudinal reinforcement were [0% (without main steel), 0.785% (4Ø6), 1.09% (2Ø6 + 2Ø8), and 1.395% (4Ø8)]. Four columns without GFRP were assigned as control columns in each main group and the rest were strengthened using GFRP sheets. In this study, different wrap configurations and the effect of different numbers of GFRP plies. Investigation into ductility using two different concepts showed enhancement in the behavior of strengthened columns with GFRP. The experimental results were compared with the results from analytical methods.