Effect of Length and Position of Side Externally Bonded FRP Sheets On the Strengthening of RC Beams Using a Progressive Damage Model

Abstract

To enhance the flexural strength of reinforced concrete beams, the traditional method is to externally bond the FRP to the soffit of the beam. How-ever, the soffit of the beam may be narrow or difficult to access for strengthen-ing purposes, especially when access is obstructed by existing structural ele-ments or when the reinforced concrete (RC) beam spans across adjacent com-partments, limiting available space. To overcome these limitations, this paper explores the feasibility of using side-bonded FRP composite which is externally bonding FRP at the side of the beam’s web as an alternative approach for flex-ural strengthening. This paper examines the critical parameters that influence the effectiveness of side externally bonded (Side-EB) FRP through a newly de-veloped finite element (FE) model created in ABAQUS. The study focuses on identifying the key factors that affect the performance of these method in en-hancing the flexural capacity of RC beams. The model was validated by com-paring its results with experimental literature, showing strong agreement be-tween predicted and observed outcomes. Once validated, the model was used to investigate the effect of length and position of FRP sheets by varying its thick-ness and utilizing different lamination scheme to study the behavior of strength-ened RC beams. A progressive damage model (PDM) utilizing user subroutine VUMAT is further incorporated considering 2D Hashin failure criterion to pre-dict the failure conditions of FRP. The results of this numerical investigation demonstrate the effectiveness of side bonded FRP as a viable alternative to tra-ditional soffit mounted strengthening method for enhancing the flexural capaci-ty of RC beams.