Flexural repair/strengthening of pre-damaged R.C. beams using embedded CFRP rods

Many reinforced concrete R.C. elements need either strengthening due to the need of increasing the service loads or repair due to overloading stress or environmental deterioration affecting these elements. In this paper an experimental program is presented to investigate the effect of using embedded CFRP rod as NSM reinforcement for strengthening/repairing R.C. beams pre-damaged by loading to different loading levels and comparing the results to those of non-preloaded beams. A total of five beams were cast and six beams were tested under four point loading. The main objective of this paper was to investigate the effect of providing one 12 mm diameter CFRP rod in addition to the existing steel reinforcement. Three beams were tested to failure directly without any preloading, whereas the other three beams were firstly subjected to preloading to different load levels. Following that these three beams were strengthened and were tested up to failure.