GFRP COMPOSITES: A MATERIAL TO STRENGTHEN REINFORCED CONCRETE BEAMS WITH WEB OPENINGS FOR SHEAR

Buildings that require mechanical and electrical services must have utility pipes and ducts. The services include air conditioning, power supply, telephone lines, network cables, sewerage lines, water supply and etc. A reinforced concrete (RC) deep beam with web openings experiences excessive cracking and deflection, as well as a decrease in beam stiffness. Enlargement of these openings near supports would reduce beams’ capacity for shear. Hence, analysis and design of such beams require careful consideration, particularly with regard to their performance. In addition, design compliance to relevant codes and standards, and selection of suitable material properties and construction techniques are needed. When such an enlargement is unavoidable, strengthening of beam for shear and flexure is necessary. In this study, the use of GFRP (Glass-Fiber Reinforced Polymer) composites for strengthening of RC beams with openings is experimentally investigated. As compared to the control beam, test results showed that using GFRP was found to be effective in increasing the shear strength of beams with openings by 40% to 60%. Test results of beams with web openings exhibited higher shear strength than the predicted values whereas for strengthened beams with GFRP, code predictions are found conservative.