Assessment of shear transfer capacity of non-cracked concrete strengthened with external GFRP strips

•Shear tests were carried out on 16 non-cracked push-off specimens.•We investigate the interaction of internal steel reinforcement and external FRP composites.•Strengthening with FRP strips increases the shear transfer capacity.•The effectiveness of FRP composites is declined by increasing internal reinforcement.•We describe the characteristic behavior of strengthened specimens.

To investigate the interaction of internal steel reinforcement and external fiber reinforced polymer (FRP) composites on the behavior of shear transfer, 16 non-cracked push-off specimens were tested. Specimens were internally reinforced with steel reinforcement ratios between zero and 1.54% and externally strengthened with different widths of Glass FRP layers. In strengthened specimens, shear transfer capacity increased from 3% to 38% compared to plain specimens. The contribution of FRP reinforcement in shear transfer capacity, as the percentage of cylindrical concrete strength (fc′), was between 0.6%fc′ and 3.7%fc′. Based on the results, the characteristic behavior of strengthened specimens is described.