Nonlinear analysis of RC deep beams strengthened with NSM CFRP anchor bars

Abstract

Studies on the effect of using externally bonded fiber reinforced polymer (FRP) laminates and near surface mounted (NSM) FRP bars on the shear strengthening of reinforced concrete (RC) beams has been widely conducted by various researchers globally. However, an innovative technique using NSM CFRP as anchor bars on the shear strengthening of RC deep beams has never been conducted. Current experimental work on NSM anchor bars has shown good enhancement in the shear capacity for the RC deep beams. This paper presents results obtained from the analytical model of the RC deep beams shear strengthened by NSM CFRP Anchor bars. The study comprises of developing four analytical models using finite element method software ANSYS Version 14. Results of the analytical model and experimental findings were compared for validation. All deep beams were simply supported and subjected to four point bending test with shear span to depth ratio av/d of 0.864. CFRP NSM bars of 5 mm diameter with 450 mm length and spaced at 100 mm (for beams R1 and R2) and 150 mm (for beams R3 and R4) were anchors into their respective beams. Similar properties from the experimental work were adopted for the analytical model. Results from the analytical model such as crack pattern, failure mode and load displacement profile were observed to have good agreement with the experimental findings. Shear capacity shows proximity between the analytical model and experimental results observed at 15 % for beams R1 and R2, and 7 % for beams R3 and R4.