Effect of existing cracks in shear strengthening of concrete girders with external post tensioning

Abstract

Deteriorated bridges all around the world are in need of replacement, or repair and strengthening. This damage is commonly caused by the overloading of bridges, due to the increasing size of heavy vehicles using the bridges today. Full bridge replacement poses the problems of high cost and disruption to traffic, so suitable methods of repair and strengthening are required. A common deterioration of these bridges is shear cracking. External post-tensioning is a method of shear strengthening girders, but existing shear cracks can limit the effectiveness of the external post-tensioning. Epoxy injection is a method of structurally repairing cracks, which could possibly be used to repair the shear cracks. If effective, this would allow the post-tensioning to effectively strengthen the member. This project is studying the shear strengthening of concrete girders using external post-tensioning, with existing shear cracks repaired with epoxy injection.