Reinforced concrete (R.C) elements strengthening using FRP (Fiber Reinforced Polymer) composite materials is a technique whose efficiency has been evaluated and proved by testing and theoretical modelling [1, 2, 3]. FRP strengthening materials are made of fibers of different nature (usually carbon, glass and aramid) combined with epoxy resin, which guarantees the bonding to the support surface. FRP strengthened R.C. members often fail due to the FRP debonding, which is caused by combined shear and tensile high stresses. Referring to the flexural strengthening of RC beams, this shortcoming should be reduced by introducing U shaped FRP strips at the end of the flexural reinforcement. In this paper, aramid connectors are presented as an alternative technique; they could be inserted in concrete beams, and bonded to the reinforcing strip with epoxy resin. In this paper, experimental results of bending tests on concrete specimens, strengthened with carbon FRP and aramid (AFRP) connectors are presented. Experimental results of strengthened beams with aramid connectors, in terms of load-deflection diagrams, load-crack opening and load-strain diagrams, are compared to results of strengthened specimens without aramid connectors. Strengthened beams failure is due to debonding of strengthening material from the support, whereas the failure mechanism of the others strengthened beams is modified due to aramid connector.
AFRP connector to prevent brittle debonding in FRP strengthened RC beams
FOCACCI, FRANCESCO
2006-01-01
Abstract
Reinforced concrete (R.C) elements strengthening using FRP (Fiber Reinforced Polymer) composite materials is a technique whose efficiency has been evaluated and proved by testing and theoretical modelling [1, 2, 3]. FRP strengthening materials are made of fibers of different nature (usually carbon, glass and aramid) combined with epoxy resin, which guarantees the bonding to the support surface. FRP strengthened R.C. members often fail due to the FRP debonding, which is caused by combined shear and tensile high stresses. Referring to the flexural strengthening of RC beams, this shortcoming should be reduced by introducing U shaped FRP strips at the end of the flexural reinforcement. In this paper, aramid connectors are presented as an alternative technique; they could be inserted in concrete beams, and bonded to the reinforcing strip with epoxy resin. In this paper, experimental results of bending tests on concrete specimens, strengthened with carbon FRP and aramid (AFRP) connectors are presented. Experimental results of strengthened beams with aramid connectors, in terms of load-deflection diagrams, load-crack opening and load-strain diagrams, are compared to results of strengthened specimens without aramid connectors. Strengthened beams failure is due to debonding of strengthening material from the support, whereas the failure mechanism of the others strengthened beams is modified due to aramid connector.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
