<title>Evaluation of residual stress in concrete structures by digital shearography</title>

Abstract

This paper presents a method for evaluating residual stresses. The approach is based on measuring the deformation due to the relief of stresses produced by a hole drilling technique. The deformation is measured by digital shearography al. In addition, the technique is extended to evaluating stresses in concrete structures. In this application, the stresses in concrete are treated as residual stresses. Since concrete materials are weak in tensile strength, one method of assessing the integrity of concrete structures is to look for the presence of tensile stresses in concrete. Unlike holography and ESPI, digital shearography does not require special vibration nor ambient light independence. These features make the method practical for detection of residual stresses in a production/field environment.