Flexural strengthening of reinforced concrete beams using CFRP: finite element validation and parametric study

Abstract

Over the last decade, the use of fiber-reinforced polymer (FRP) composites for enhancing the performance of reinforced concrete (RC) structures has gained popularity due to its outstanding mechanical performance. In this study, novel advancements are achieved through the development of a three-dimensional ABAQUS model that explicitly captures the interactions between critical parameters, specifically CFRP length and thickness. For this, the finite element model was validated through two experimental studies on RC beams from the literature. Each beam featured a rectangular cross-section and was subjected to a four-point loading test, with variations in the length and strip configuration of the carbon fiber-reinforced polymer (CFRP) plate. A perfect bond model was applied at the concrete-CFRP interface, while the concrete behavior was simulated using the concrete damage plasticity (CDP) model. The analysis results showed a good correlation with experimental studies. The parametric study revealed that optimizing CFRP length and thickness significantly improves load capacity, with diminishing returns beyond certain thresholds. Longer CFRP laminates significantly enhance both load-carrying capacity and total energy absorption. The ultimate load enhancement follows a near-linear relationship with the bonded area. Key results show longer CFRP laminates substantially increase load capacity and energy absorption, while a CFRP thickness of 1.2 mm optimizes strength, ductility, and energy absorption. Beyond this thickness or optimal length threshold, gains diminish significantly and ductility reduces. These findings offer insights into CFRP strengthening strategies and highlight the FEM model’s effectiveness in predicting structural behavior.