Flexural behavior of continuous RC beams strengthened with externally bonded CFRP sheets

Abstract

The survey of the previous literature showed the need for research studies on the behavior of strengthened continues reinforced concrete (R.C.) beams. To meet this need, this paper aims to study the effect of strengthening schemes on the flexural behavior of continuous R.C. beams under a wide range of parameters. Seven beams were constructed experimentally and studied to discuss two parameters which are the length and number of layers of carbon fiber reinforced polymers (CFRP) sheets. Also, finite element Models (FEM) was developed by using ANSYS. The experimental results were used as verification for the FEMs’ results. A parametric study was conducted by using 540 specimens to discuss more parameters. Test results showed that the common mode of failure in hogging zone is a rupture, while de-bonding occurs at the sagging zone. When the number of layers has increased the mode of failure is likely de-bonding. The parametric study concluded; the reinforcement ratio affects the failure mode by 22%. The fcu has an effect upon many variables up to 40%. A relation was deduced between the variables. The failure strain at mid-span and above the middle support is deduced by using an equation based on the gene expression programming (GEP). By using this relation, the designer will be able to predict the mode of failure and the CFRP sheets’ failure strain of any strengthened equal spans continuous R.C. beam. Keywords: CFRP sheets, Continuous R.C. beams, Strengthening, Parametric study, Finite element modeling, GEP