Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

Abstract

This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer (CFRP) layer under long-term load action that lasted for 330 d. We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest. The conducted experiments showed that the additional anchorage influences the slip of the external layer with respect to the strengthened element. Thus, concrete and carbon fibre composite interface stiffness decreases with a long-term load action. Therefore, the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.