*3.2. Peak Stress and Ultimate Strain*

A summary of the peak compressive stress sustained and the ultimate strain for all of the specimens is presented in Table 4. The average peak stress for control specimen SQ-LS-R0-CON was slightly higher than the control specimen SQ-LS-R26-CON. This could be associated with the larger bearing area of the SQ-LS-R0-CON specimen as compared to the control specimen SQ-LS-R26-CON. The low-strength concrete specimens demonstrated an 83%, 103%, and 137% increase in the peak compressive stress due to two, four, and six GFRP wraps, respectively. The corresponding improvement in the ultimate strain was observed at 82%, 194%, and 658%, respectively. Similarly, a considerable improvement in the peak compressive stress of high-strength specimens in Group 1 was also observed as two, four, and six GFRP wraps enhanced the peak compressive stress by 50%, 71%, and 84%, respectively, whereas the enhancement in ultimate strain was 70%, 159%, and 134%, respectively. Group 2 specimens also demonstrated a substantial improvement in the peak compressive stress and strain. The peak compressive stress of the low-strength specimens was improved by 116%, 210%, and 278%, respectively. At the same time, the ultimate strain was enhanced by 222%, 495%, and 752%, respectively. The high-strength specimens exhibited an increase of 84%, 364%, and 563% for the peak compressive stress due to two, four, and six GFRP layers, respectively, whereas the ultimate strain was increased by 84%, 364%, and 563%, respectively. The above discussion concerning Table 4 suggests that the LC-GFRP resulted in a substantial improvement in the peak compressive stress and ultimate strain, which is crucial given the brittle nature of the concrete. Overall, the % increase in peak stresses of the GFRP-confined specimens with 0 mm corner radius was lower than the GFRP-confined specimens with a 26 mm corner radius due to the premature rupture of LC-GFRP at sharp corners.

