Investigation on Effects of Variables on Shear Capacity of Precracked RC T-Beams with Externally Bonded Bi-directional CFRP Discrete Strips

Abstract

This study aims to investigate the shear performance of partially precracked Reinforced Concrete (RC) T-beams bonded externally with bi-directional Carbon Fiber Reinforced Polymer (CFRP) discrete strips. A series of twelve RC T-beams are fabricated with internal transverse steel reinforcement and subjected to four-point and three-point bending systems. The external CFRP reinforcement strips are applied on the web and soffit of the beam with two-component epoxy system. The parameters investigated in the experimental program included (i) longitudinal tensile reinforcement ratio, (ii) shear span to effective depth ratio, (iii) spacing, and (iv) orientation of discrete CFRP strips. The experimental results show that the bi-directional CFRP discrete strip reinforcement significantly increases the shear capacity between 18 and 54% over the control beams. It is found that the test variables have significantly influenced the shear capacity of the CFRP strengthened beams. This study also validates the obtained experimental results with different existing theoretical models.