Concrete surface strain measurement using Moiré fringes

Evaluation of the stress state of concrete in prestressed concrete (PC) structures is extremely important for construction management and O&M (operation and maintenance). We developed a strain visualization sticker using the principle of Moiré fringes, which makes it possible to read the approximate strain value of a concrete surface directly with the naked eye and also enables remote, noncontact measurement of strain with high accuracy by a digital camera, etc. This paper presents an outline of the developed strain visualization sticker and the results of verification of its performance.