Concrete surface strain measurement using Moiré fringes

• A strain visualization sticker is used the principle of Moiré fringes.
• A strain visualization sticker enables remote, noncontact measurement of strain with high accuracy.
• Strain measurement is used an ordinary digital camera or similar device without using electrical elements.

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.