Retrofitting of Distressed Post-tensioned Concrete Members by External Post-tensioning

Many of the existing prestressed concrete bridges are in distressed condition in India and abroad. Deterioration occurs due to various reasons. This has considerably reduced the load-carrying capacity of many prestressed concrete (PSC) bridges. Therefore, it is necessary to improve the retrofitting solutions to recover the load-carrying capacity that is lost due to distress. One of the prime techniques that is being used for retrofitting of existing bridges is external post-tensioning. However, behaviour of the retrofitted PSC members is still not understood in depth. It is intended to report the behaviour of retrofitted post-tensioned concrete specimens by external post-tensioning, on which distress was induced by the combined effect of loss of prestress and fatigue deformation before retrofitting. As a result of retrofitting, the ultimate load-carrying capacity has increased by 33% with reference to the fully prestressed control beam specimen. The ductility is observed as 94% of the ductility of the control specimen.