Predicting the flexural and shear behavior of LWRC beams strengthened by NSM GFRP bars using the DIC method

Purpose This research explores the potential of employing DIC method to assess the load-deflection behavior of lightweight reinforced concrete (LWRC) beams enhanced with near-surface-mounted (NSM) glass fiber-reinforced polymer (GFRP) bars. Design/methodology/approach This research explores the potential of employing DIC method to assess the load-deflection behavior of LWRC beams enhanced with NSM GFRP bars. An experimental study was presented to investigate the behavior of the strengthened LWRC beams. The lightweight expanded clay aggregate (LECA) was utilized to substitute the natural coarse aggregate (NCA) in concrete mixture to produce LWRC beams. The experimental program comprised 14 LWRC beams subjected to four-point loading until a failure. The beams are classified into two groups: the first group comprised of seven LWRC beams reinforced to fail by flexural mode, while the second group included seven LWRC beams reinforced to fail by shear mode. Within each group, one beam served as the control, lacking any reinforcement, while the remaining samples were strengthened using NSM GFRP bars arranged and configurated in various patterns. In addition, this study uses the DIC method to capture the strain profile and load-displacement behavior of the NSM strengthened beam specimens with deferent locations, numbers, diameters, bond lengths, spacings, angle of inclinations and materials of the NSM GFRP rods. The experimental results showed improvements in the load-carrying capacity of the LWRC beams when NSM GFRP bars are used for flexural and shear strengthening, compared to that of control specimens. Further, the DIC results were compared with those obtained experimentally, revealing that the DIC method offers higher accuracy compared to visual inspection, particularly in the analysis of cracking loads. This DIC capability enables early detection of potential issues before cracks happen in the specimen. Findings The experimental results showed improvements in the load-carrying capacity of the LWRC beams when NSM GFRP bars are used for flexural and shear strengthening, compared to that of control specimens. Further, the DIC results were compared with those obtained experimentally, revealing that the DIC method offers higher accuracy compared to visual inspection, particularly in the analysis of cracking loads. Research limitations/implications The study is applied on simply reinforced concrete beams under two-points loads. Practical implications This DIC capability enables early detection of potential issues before cracks happen in the specimen. Social implications The study helps in sustainable using of reinforced concrete building. Originality/value The study employed the DIC method to assess the load-deflection behavior of LWRC beams enhanced with NSM GFRP bars.