Strengthening of reinforced concrete beam-column joints by means of fastened C-FRP ropes

The efficiency of using C-FRP ropes as external superficial reinforcement to strengthen beam-column connections in reinforced concrete structures with regard to seismic requirements is investigated experimentally. The method is an easy-to-apply, effective method for locally increasing the load-bearing capacity of beam-column connections in existing buildings. To strengthen the beam, external C-FRP ropes are placed in slots along each side of the beam at the top and bottom. The test results with test specimens on a scale of 1:1 in undamaged condition (JA0) and in strengthened condition after pre-damage (JA0b) are analysed and compared. From the comparative representation of the hysteresis reactions, it is concluded that the strengthened test specimens show an improved hysteresis reaction in all cases examined compared to the corresponding test specimens without strengthening. Comparisons of the damage index values and the equivalent viscous damping values obtained from the test results are also presented and commented on in order to enable objective and well-founded conclusions to be drawn. It can be concluded that the use of C-FRP ropes as external reinforcement is suitable as an efficient and easy-to-handle strengthening technique in all cases investigated.