Shear strengthening of RC beams using EBRIG CFRP strips: a comparative study

Abstract

The current research presents the behavior of reinforced concrete (RC) beams strengthened in shear with externally bonded reinforcement in grooves (EBRIG) laminates and verifies its experimental results with a numerical tool and analytical formulations. For this purposes, eight RC beams were casted and divided into two series to study the interaction between carbon fiber reinforced polymer (CFRP) laminates and the internal steel reinforcements. All the specimens with 200 $\times$ 300 $\times$ 2000 mm in size, were subjected to a 4-point static loading and their load-carrying capacity were compared. Concrete damaged plasticity model was utilised for the analysis of RC beams. The experimental results showed that, the EBRIG method increased the shear capacity in beams with and without stirrups by an average value of 40% and 69% respectively, relative to their corresponding controls. Moreover, the premature detachment of laminates was postponed and the specimens failed by CFRP rupture. Also, the finite element model revealed a good estimation of load-deflection curves and predicted the failure mechanism of tests, accurately. Based on the results of analytical models for predicting shear contribution in conventional methods, the proposed formulations can be employed for estimating the shear gain due to the EBRIG laminates.

Keywords:

• CFRP
• shear strengthening
• externally bonded reinforcement in grooves (EBRIG)
• finite element method
• analytical models

Acknowledgements

The authors would like to thank Eng. Morovvati in Maat Beton Company for providing the ready-mix concrete.

Funding

This work received no financial support.