Comprehensive review of noncontact sensing technologies for bridge condition monitoring and assessment

Abstract Bridges play a vital role in modern transportation networks. Nevertheless, the degradation of their materials, combined with the effects of natural disasters (e.g. earthquakes, floods, rockfalls, landslides), can result in decreased performance or even collapse. Therefore, monitoring the health of bridges is essential to maintain the safety and integrity of highway and railway systems. Noncontact sensing technologies provide effective solutions for bridge condition monitoring and performance assessment, as they can gather data without direct interaction with the structure. This paper provides a comprehensive review of the latest noncontact sensing technologies employed for bridge condition monitoring, detailing their principles, benefits, drawbacks, and applications. Firstly, the recent advancements in vision sensing technology for detecting defects, measuring deformations, vibrations, cable forces, vehicle loads, pedestrian-induced impact force, and monitoring vessel collision with bridges are summarized; secondly, the laser scanning technology for three-dimensional model reconstruction, full-field deformation measurement, and quality inspection of bridges are examined; thirdly, the use of microwave radar technology for measuring deformations, vibrations, and cable forces in bridges is investigated. Finally, the paper outlines future trends in noncontact sensing technologies for bridge condition monitoring and evaluation. This comprehensive review offers valuable insights for engineers and researchers in the field of civil engineering.