Condition monitoring of bridges with non-contact testing technologies

The vast number of deteriorated bridge infrastructure highlights the importance of implementing efficient and timely maintenance and rehabilitation strategies. Non-contact testing (NCT) technologies are potential tools for bridge condition assessment, facilitating fast and easy measurement with minimal traffic disruption, compared to conventional methods. The foremost objective of this study is to conduct a comprehensive review of the common NCT technologies for concrete bridge condition monitoring including defect detection, rebar corrosion, delamination, and cracking. Four NCT technologies, namely, ground penetrating radar, close-range photogrammetry, infrared thermography, and terrestrial laser scanning have been identified and analysed in depth. The review compiled one hundred and thirty-five laboratory and field studies, spanning from 2000 to 2019, on non-invasive assessment of bridge condition monitoring. In addition to comparison of stand-alone NCT methods, the study analysed integrated NCT systems, data acquisition tools, and processing and simulation platforms. Additionally, challenges and future perspectives of the reviewed NCT technologies are highlighted.