Flexural Analysis of RC Rectangular and T Beams Strengthened with NSM FRP Reinforcement

摘要

In recent years, the repair of damaged reinforced concrete members using Near surface Mounted (NSM) technique has proven its success in structural rehabilitation and upgrade. The NSM technique using carbon fiber reinforced polymer (FRP) laminate strips is now a well-established process for the strengthening/retrofit of reinforced concrete structures. The amount of analytical studies for predicting the flexural capacity of RC beams strengthened with carbon FRP laminates using NSM technique is constantly rising to the point that a design guidelines to such applications were introduced. This paper investigates the flexural behavior of reinforced concrete beams strengthened with carbon FRP laminates using NSM technique. The objective of this study is to provide an efficient and direct computational analysis for the evaluation of the flexural strength capacity of the carbon FRP reinforced concrete sections. The analysis is based on common principles of equilibrium equation and compatibility of strains of simply and doubly reinforced rectangular and “T” concrete sections. To ensure ductile failures, expressions for upper and lower values of the characteristic carbon FRP reinforcement ratios were derived using the CBA 93 model for concrete. Design nomographs to materialize the implementation of the procedure were developed and a parametric study was performed. The solution, using the developed equations is compared to some experimental data available in the literature. The comparison showed the validity and the effectiveness of the present design equations in accurately estimating the flexural capacity of simply and doubly reinforced concrete rectangular and “T” sections strengthened with carbon FRP laminates strips.