Fatigue of high strength concrete beams pretensioned with CFRP tendons

The research investigates the fatigue resistance of high strength concrete beams prestressed with CFRP tendons. The fatigue performance of bare CFRP tendons has been found to be very good. However, the influence of stress concentrations at concrete crack locations on the fatigue behaviour requires further verification. In the main experiments, concrete beams pretensioned with CFRP tendons were subjected to cyclic loading. The maximum and minimum loads were chosen so that the beams were cycled above and below the cracking load. Thus, as the cracks opened and closed the concrete crack faces rubbed against each other and potentially against the tendon. It is concluded that the fatigue resistance of CFRP tendons does not appear to be affected by stress concentrations at crack locations since debonding occurs and reduces the strain concentrations.