Saw‐cut method verification for determining the most important factors influencing its applicability

Abstract The current situation with prestressed structures raises questions about the ways how to determine residual prestressing which is the crucial factor for the evaluation of the prestressed structure. Therefore, this study aims to enhance existing knowledge of the so‐called Saw‐cut method which is considered a non‐destructive indirect technique. The presented study focuses on the determination of various factors which could influence the applicability and accuracy of this method such as both compressive and tensile normal stress release, the type of measuring instrument (linear foil strain gauge or newly developed FBG sensor), and the length of the normal stress release recording (up to almost 9 h). The obtained results suggest that tensile normal stress release could be more problematic for the evaluation than compressive normal stress release. Moreover, the application of FBG sensors seems to be more precise but also more complicated regarding the installation, recording and costs. Finally, the time span of the measurement can influence the residual normal stress release. For practical reasons, 60 min after the performance of the final sawing should be sufficient. Finally, when used at locations with adequate compressive normal stress, the Saw‐cut method seems to be a promising tool for prestressing evaluation.