Possibilities of Indirect Techniques for Prestressing Analysis of Existing Structures and Bridges

Determining the load-carrying capacity of existing bridges is a crucial task in assessing the current reliability and remaining service life of prestressed concrete structures and bridges. Nowadays, prestressed bridge structures that have been in operation for more than sixty years are proving to be problematic from the reliability point of view. If we want to comprehensively assess the reliability level of these structures, it is necessary to determine the current level of the prestressing as accurately as possible. This fact leads to the need to apply different methods that can determine these values. The paper is focused on the analysis of prestressing using indirect or analytical-experimental methods. Specifically, the Structural Response Method and the Saw-Cut Method. These techniques were tested both on prestressed members, in laboratory conditions, but mainly directly in-situ on a post-tensioned bridge. Finally, the experimental results are compared with the theoretically determined levels of prestressing.