Effect of polymer-strengthened webs on notched concrete beams

Concrete beams with notched ends are commonly used in construction. The strut and tie model is a familiar design method used for understanding such geometric discontinuities in concrete structures. The effects of applying carbon fibre-reinforced polymer laminates to strengthen the webs of notched-end concrete beams were studied in this work. To this end, 12 beams with two levels of shear reinforcement were cast and the effect of web strengthening the notched ends with polymers was studied. It was found that the beams with polymer strengthening showed up to 17% more load-carrying capacity than respective control beams without polymer strengthening. Furthermore, carbon fibre-reinforced polymer strengthening applied at an orientation of 45° was found to be more effective than that at 90°. Failure loads for both orientations were up to 9% higher than those of the respective control specimens. Retrofitting failed beams with polymer web strengthening resulted in the achievement of 90% of the failure load in comparison with the respective control beams.