Fatigue performance of damaged RC beams rehabilitated with GGBS based ultra high performance concrete

The study investigates the fatigue behaviour of damaged RC beams strengthened with GGBS based UHPC strips. Parent RC beams are pre-damaged under static and fatigue loading conditions. The damaged beams are rehabilitated with thin UHPC strips of various thicknesses (5, 10 and 15 mm) and tested under fatigue load until failure. The results illustrate that the fatigue damaged beams rehabilitated with thin UHPC strip (5 mm) can efficiently restore its fatigue life despite the severity of the damage. From experimental studies, the mechanism of the strain that exists in the rehabilitated RC beams subjected to static and fatigue damage is illustrated. Twostage finite element analyses have been performed to predict the fatigue behaviour of damaged and rehabilitated beams. Various aspects considered in the numerical analysis include concrete damage model, failure criterion, stress crack-width relation and fracture energy. The deviation in the predicted numerical and the corresponding experiment results are lesser than 25%.