TITLE:
Review of Digital Image-Based Monitoring for Long-Term Tracking of Bridge Deformations
AUTHORS:
Kora Farid Carlos Yarou, Valery Kouandete Doko, Boris Ganmavo, Thede Agbelele, Mohamed Gibigaye
KEYWORDS:
Image Analysis, DIC, SHM, Photogrammetry, Computer Vision, Deformation
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.16 No.9,
September
18,
2026
ABSTRACT: Over the past two decades, monitoring the condition of bridges has become a central concern for infrastructure managers worldwide. The main reason is simple: a large share of the existing bridge stock was built between the 1950s and the 1980s, meaning that many of these structures are now approaching the end of their originally intended service life. This is compounded by growing traffic loads, often far exceeding the design assumptions of the time. In this context, traditional monitoring methods based on point sensors—such as strain gauges, LVDT sensors, or accelerometers—prove insufficient to capture the overall behavior of a structure: they provide only local information, at a limited number of points, without allowing reconstruction of the complete deformation field of the structure. This literature review focuses precisely on digital image analysis techniques developed to address these shortcomings. It draws on a critical examination of two hundred and four articles published between 2000 and 2026 in the Scopus and Web of Science databases, selected according to the PRISMA protocol, and has been updated to incorporate work published in the first half of 2026 on digital twins, multimodal drone inspection, and recent state-of-the-art reviews devoted to DIC and optical acquisition modules. Digital Image Correlation (DIC) occupies a central place in this state of the art, both in its theoretical aspects and in its experimental applications on various types of bridges. Also covered are UAV photogrammetry, LiDAR laser scanning, and the recent contribution of deep learning to automatic defect detection. The review aims to present not only the performance achieved, but also the practical conditions of implementation, sources of error, the limitations of current approaches, and the questions that remain open. It concludes with a forward-looking discussion of next-generation monitoring systems.