In recent years, the bonding of fiber reinforced polymer (FRP) has been accepted as an effective and efficient method for strengthening and retrofitting concrete structures. A lot of research efforts have focused on the flexural strengthening of concrete beams with FRP plates. However, in most investigations, experimental testing was limited to simply supported beams under three-point or four-point bending, which may not represent the real conditions of the strengthened members. In this investigation, to study the failure of the FRP strengthened beams under practical situations, a special waffle tree system is designed to test the beam specimens under quasi-distributed loading conditions. According to the test results, for beams bonded with thin FRP plate, enhancing load uniformity can significantly increase the moment capacity without changing the failure mode. However, for beams with thick FRP plate, there will be a change of failure mode from crack-induced debonding to concrete cover separation and a corresponding reduction in the moment capacity. The transition of the failure mode indicates that the load uniformity plays an important role in determining the failure behavior of the strengthened beams. For both crack induced debonding and plate end failure (concrete cover separation), several existing analytical models have been employed to calculate the ultimate debonding moment and compared with the test results. The results show that most existing models are not able to properly predict the failure behavior of the strengthened concrete beams under different levels of load uniformity
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.