Effect of CFRP strengthening on web of steel i-beam

Abstract

This study is aimed to strengthen the structural steel I beam with carbon fiber reinforced polymers (CFRP) composites to its web to increase its shear strength capacity. Lightweight Beam LB-100 @ 5.1 Kg/m and LB-115@ 8.1 Kg/m is used for this purpose. CFRP have light weight and high-strength as compare to other types of FRPs, so it can be used for strengthening purpose instead of using conventional methods of repair such as replacement and other. The web portion of the I-beam is made rust free to achieve proper bonding between the web and fiber sheet. A web of the beam is strengthened by carbon fiber reinforced polymer (CFRP) strips in layers with the help of adhesive. The beam with CFRP is cured in air for 48 h before testing. Experimentation is done at the UTM of 100 Ton capacity. A three point bending tests were performed on various beams and results show that the load carrying capacity of a strengthened beam is increased by 20 to 35% as compared with control beam (non-strengthened) and the local failure of beam is also avoided. It is observed that the deflection of strengthened beam is also reduced as compared to a non-strengthened beam. So, this technique of strengthening can be used to improve the performances of various old structures in civil engineering which undergoes loss of strength due to corrosion.