Retrofitting of shear damaged reinforced concrete beams using external clamping

The importance of the maintenance, rehabilitation, and strengthening of reinforced concrete members has increased due to various factors including increase in traffic volume and weight, structural aging and environmental impact. While various strengthening methods such as external post tensioning has been used for retrofitting existing structures, recent investigations have shown that the efficiency of shear strengthening using such methods is significantly reduced by the presence of existing shear cracks. The effect of existing shear cracks is a complex function that depends on a number of parameters including crack width, crack inclination, shear reinforcement ratio and concrete strength. In order to investigate the possible alternatives to reduce the effect of such shear cracks, an experimental investigation was carried out on the potential use of external clamping to reduce the effect of existing shear cracks. Eight reinforced concrete beams were tested with different clamping arrangements. The effect of existing shear cracks on such external clamping technique is discussed in this paper highlighting the importance of repairing existing cracks using a suitable repair technique such as epoxy injection.