Comparative study of steel I-beam strengthened with CFRP and steel plate as a web stiffeners

This study investigates the use of Carbon Fiber Reinforced Polymer (CFRP) plates as stiffeners to enhance the web of a steel I-beam. CFRP offers a lightweight and high-strength compare to steel, making it easier to handle during construction activities. Consequently, instead of relying on conventional methods for strengthening steel sections, CFRP plates present a superior alternative for evaluating their effectiveness in improving the structural performance of steel beams. Indian Standard Light Weight Beam (ISLB) 115, weighing 8.2 kg/m, serves as test specimen. The web of the beam is meticulously prepared to ensure optimal bonding of CFRP plates, thereby minimizing the risk of failure during testing. CFRP plate stiffeners are symmetrically applied to both sides of web using adhesive and are positioned directly under the point load. Testing is conducted using a Universal Testing Machine (UTM) with a capacity of 200 tonnes. The results indicate a significant increase in the Load Carrying Capacity (LCC) of strengthened beam compared to control beam (without stiffeners). Additionally, local failure of compression flange is completely mitigated. A comparative analysis of beams reinforced with steel stiffeners and CFRP plate stiffeners reveals that the LCC remains largely unchanged. Finite element analysis of both cases shows a smaller percentage change when compared with experimental data. This suggests that CFRP plate stiffeners can effectively used to strengthen steel sections, offering a simpler and quicker alternative to conventional steel stiffeners. Furthermore, elastic response of strengthened beam demonstrates an improvement over the control beam, enhancing its overall elastic behavior.