Interfacial stress analysis of a damaged RC beam strengthened with advanced composite porous plates

In this research, a detailed analysis was conducted on the interface shear stresses in damaged reinforced concrete (RC) beams strengthened with composite material plates (P-FGM and E-FGM). Various conditions were considered, including the application of a uniformly distributed load, an arbitrarily positioned point load, and two symmetric point loads. Additionally, the effects of hygrothermal conditions were incorporated. The analysis was based on linear elastic theory. The presence of pores in the reinforcement plate was accounted for, with these pores categorized into different forms to ensure comprehensive consideration of this parameter. Comparisons between the proposed model and existing analytical solutions from the literature not only validate this new method but also demonstrate its accuracy and relevance. These results confirm the ability of the approach to provide reliable predictions and emphasize its potential for solving complex problems related to the modeling of reinforced systems, aligning with recognized theoretical outcomes. A parametric study was conducted to examine the sensitivity of interface stresses to various parameters, including plate homogeneity, porosity, plate and adhesive stiffness, plate thickness, and the damage factor. In the present model, a shear stress of 1.823 is achieved for CFRP in undamaged beams, which is within 1% of the highest value reported in other references but 8% lower than the maximum. For GFRP, the present model shows a 10% improvement over other references, reaching 1.2174. In damaged beams, steel achieves a shear stress of 2.266 in the present model, which is within 8% of the highest value in the references, while P-FGM (Al2O3) provides a balanced alternative at 1.457. This study establishes a solid foundation for future analyses of damaged reinforced concrete beams reinforced with composite plates, whether advanced or conventional, paving the way for significant advances in rehabilitation methodologies.