The Performance of Post-Tensioned Bridges

In the course of the major upgrading and extension of the highway networks in the last fifty years, the use of post-tensioned concrete has been found to be an economically competitive form of construction and this has enabled concrete to be used for bridges with significantly longer spans than was previously thought possible. The paper briefly reviews the development of post-tensioned concrete bridges over the last fifty years and difficulties encountered in Europe with building and monitoring the bridges. The types and magnitude of problems as reported in several countries will be reviewed. Discussion will be presented on certain methods of investigating the in-situ condition of post-tensioning systems. The resulting improvements in the quality of the investigations will be discussed in the paper. The three-phase approach to Special Inspections is outlined and the findings of research and site investigations discussed together with the implications for bridge owners and managers.