Analytical studies on externally post tensioned concrete girders with existing shear cracks

In recent years, the important of the maintenance, rehabilitation, and strengthening of reinforced concrete bridges has increased due to various factors including increase in traffic volume and weight, structural aging and exposure to adverse environmental conditions. External post tensioning is a suitable technique for rehabilitation or strengthening of concrete bridges. While external post tensioning have been effectively used for the flexural strengthening of existing bridges, recent experimental investigations have shown that the efficiency of the shear strengthening using external post tensioning is significantly reduced by the existing shear cracks. The effect of the existing shear cracks is a complex function depending on a number of parameters including width of the cracks, crack inclination, shear reinforcement ratio and concrete strength. In order to analytically investigate the effect of such shear cracks in externally post-tensioned bridge members, numerical analysis was carried out using ABAQUS software. This paper focuses on a simply supported reinforced concrete girder strengthened by external tendons with existing shear cracks. The accuracy of this type of analytical modelling is verified by comparing with the experimental results conducted on similar reinforced concrete girders.