Overview of external post-tensioning in bridges

Over the last few decades, there has been a rapid increase in the volume and weight of heavy vehicles using national road networks. At the same time, more than fifty percent of the bridge structures are over forty years old all around the world. Consequently deterioration of the existing bridges due to increasing traffic loads, exposure to adverse environmental conditions and structural aging has become a major problem today. These bridges are not able to cope up with current traffic requirements and require either weight restriction, strengthening or even total replacement. Several methods developed to strengthen such bridges. Due to economical reasons, design engineers are looking for cost-effective strengthening methods for bridges. External post-tensioning is one of the widely used strengthening techniques due to its advantages. The external post-tensioning has been applied mainly in bridges and the technique is growing in popularity because of the speed of construction and minimal disruption to traffic flow. This paper briefly discusses the use of external post-tensioning in new bridges and strengthening of existing bridges. Some of the recent research and development on the applications of external post-tensioning for bridge rehabilitaion are also discussed.