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.