Introduction of Non-Destructive Highway Inspection Methods using High Definition Video and Infrared Imaging Technology

摘要

The current budget shortfalls being experienced by nearly all highway and bridge owners aroundthe world serve to jeopardize the efficient management and maintenance of highway structures.The resulting consequences of this dilemma include premature structure deterioration, higherrehabilitation and repair costs and, in some instances, a higher probability of premature structuralfailure. Informed and proper bridge maintenance requires constant monitoring of structuralconditions, yet most of the highway bridge inspections performed in Japan involve visualinspections, which are costly in both time and labour. More efficient, objective and safer bridgeinspections can be realized only through technological improvements.NEXCO-West, one of Japan’s major toll road operators, has introduced a combination of new highdefinition video (HDV) and infrared (IR) thermographic technology that together serve to reduceinspection costs and increase inspection result accuracy and reliability. The high definition videocamera (HDV) records the surface condition of the concrete structures, while application of IRsupported thermographic assessments support analysis of structural integrity through analyzingtemperature variations within the structure at different times of the day; operating on the principlethat damaged and/or deteriorating concrete demonstrates more temperature variation throughout theday than do sound structural elements.This paper describes the mechanisms of these inspection methods and introduces some examples ofpractical on-site application to highway bridge superstructures. The technologies offer a powerfultool for decision-making engineers responsible for developing highway maintenance strategies andcontribute to efficient and smart infrastructure management.