Evaluation of residual prestress in concrete beam with modified saw-cut method

In the last few decades, prestressing techniques have been used to build very important structures, infrastructures, and bridges. The serviceability and safety of prestressed concrete elements depend on the effectiveness of the prestressing. Consequently, there has been a deep effort to develop tools and procedures to accurately estimate prestress loss. Among techniques, static identification using saw-cut method and strain measurements has been improved to achieve an accurate and reliable results in terms of prestress loss evaluation. This paper represents an experimental campaign carried out on prestressed concrete beams of different ages, a comparison between the modified saw-cut based on strain measurements and the destructive cracking method has been performed. The attention is focused mainly on calculation of stress and strain in the notch of saw-cut to analytically detect prestress losses. Comments and recommendations will be made at proper places, while concluding remarks including future research directions will be presented at the end of the paper.