Experimental and numerical investigations on RC beams flexurally strengthened utilizing hybrid FRP sheets

Abstract

During structural evaluations and inspections of existing buildings to determine their soundness, a number of structural defects are usually identified, especially in older buildings whose functional lifespan and safety could be increased by timely retrofitting or rehabilitation operations. Due to their superior performance as reinforcing material for restoration projects, fiber reinforced polymer (FRP) composites are widely used in various civil engineering applications. This research study focuses on the execution of, reinforced concrete (RC) beams whose flexural strength is significantly improved with the usage of hybrid-FRP (HFRP) composites, a combination of aramid-FRP (AFRP) and glass-FRP (GFRP) laminates/sheets. Five RC beams are cast and tested using a four-point bending configuration as sample for experimental and numerical studies. The steel reinforcement ratio used for designing RC beams is 0.47%. The thickness of HFRP laminates is the main varied test factor used in this investigation. One of the five beams is designated as the control beam, while the other four were strengthened using HFRP laminates. The findings of the present study demonstrate that using HFRP laminates effectively improves the load-bearing capability of the RC beams. However, using thicker HFRP sheets to increase strength is not advised because flexural strength is controlled by epoxy properties and surface quality of the concrete. According to the experimental findings, the increase in the ultimate load of the HFRP3-strengthened beam (SH3) is noted to be 202.63%, as compared to the control beam. Furthermore, the experimental outcomes are compared with that of the finite element (FE) analysis using a finite element software and it is observed that there is good agreement between these results.