STRUCTURAL BEHAVIOR OF GFRP-CONCRETE COMPOSITE COLUMNS UNDER AXIAL LOAD

Glass Fiber Reinforced Polymer (GFRP) is emerging as an effective alternative to traditional steel in construction due to its superior ability to withstand high loads, light weight, corrosion resistance and low maintenance costs. Optimizing the design of GFRP I-section can lead to significant savings construction costs. The main objective of this study is to understand the effect of introducing GFRP I-section internally on the load bearing capacity of Reinforced Concrete (RC) columns with and without fire. Four RC-column specimens were tested with a square cross-section of 160 mm side dimension and 1540 mm height. I-shaped GFRP section with 5.5 mm thickness for web and flanges, 80 mm flange width, and 100 mm total height is fixed in the center of section of column specimens .The specimens are divided into two groups. The first group has two conventional RC tested column specimens which one exposed to the fire 500°C for 90 minutes and the other without fire. The second group has two RC columns specimens reinforced with GFRP I-section which one exposed to the fire 500°C for 90 minutes and the other without fire. This study has shown that GFRP I-section composite columns exhibit excellent strength and high resistance to axial load than the conventional reinforced concrete columns. The maximum bearing capacity for the composite columns with (GFRP) I-section increased 17% more than the conventional RC columns. The maximum bearing capacity for the composite columns with (GFRP) I-section under the fire decreased 39% more than the composite (GFRP) columns without the fire, and decreased 14% more than the conventional RC columns. By different codes the theoretical axial load is calculated for tested specimens. The Finite element analysis was used to verify experimental results for studying additional parameters are the effect of concrete compressive strength, the steel yield strength, the reinforcement ratio, and the GFRP plate and I-section ratio of RC composite columns.