Experimental Investigation of Steel Beams with Mechanically Reduced Sections Strengthened with Basalt Fiber–Reinforced Polymers

Abstract

Steel elements subjected to harsh environments can corrode and experience degradation in their performance, which could compromise the integrity of the structure. Ensuring the safety of corroded steel structures requires conducting a series of inspections and repairs, especially for critical structural elements. Traditional repair methods, while effective in many cases, involve extensive labor and are typically costly. Recent studies have proposed fiber-reinforced polymers as a cost-effective method to repair corroded steel cross sections. However, most of the studies did not investigate the effects of utilizing these repair materials on the entire structural performance, including ductility. In addition, these studies were focused on the use of carbon fibers with limited attention to the use of basalt fibers. Here, we conduct a series of full-scale experimental tests to investigate the impact of mechanical section reduction, representing corroded sections, on the flexural behavior of steel beams and the effectiveness of different repair materials in enhancing their structural performance. Two retrofit materials, including carbon fiber-reinforced polymer (CFRP) and basalt fiber-reinforced polymer (BFRP) sheets, are utilized. The results show that the flange and web section reduction lower the beams yielding load by 10% and 8%, respectively, compared with a beam with no section reduction. Utilizing CFRP and BFRP patches can partially restore the beams’ ductility; however, the BFRP is outperforming the CFRP in improving their ultimate strength by 10% and enhancing their ductility by 10%.