Shear strengthening of cracked RC beam using external post-tensioning

Abstract

[Abstract]: Currently several bridges are considered as inadequate for the current traffic loads due to various problems including rapid increases in the traffic volume and vehicle weights; exposure to adverse environmental conditions and structural aging. These bridges require weight restriction or strengthening or even total replacement. Strengthening of such bridges is cost-effective for bridge engineers rather than total replacement. External post-tensioning is considered as one of the effective methods to strengthen bridge structures. Unlike flexural strengthening, the shear strengthening of existing structures using external post-tensioning has not been investigated adequately. The existing shear cracks may have substantial effect in shear strengthening of structural members using conventional external post-tensioning. Even most of the current design codes do not have provision for the existing shear cracks (except some of repair guides recommended these cracks should repair prior to the strengthening). This paper presents an experimental attempt to investigate the effect of the existing shear cracks in such members strengthened with external post-tension.