This study evaluates thermal movements of an existing bridge using digital image processing technologies. Digital images are acquired from smart phones. Thermal movements which extracted from bridge bearings' images are compared to the results of conventional displacement transducers. It is concluded that the image-based process for measuring thermal movements of bridges is accurate, practical and cost-effective.

In this study, a MFL (Magnetic Flux Leakage) image based 3D inspection system which is incorporated into a cable climbing robot was investigated for Steel Cable NDT of Cable-stayed Bridge and Suspension Bridge. Firstly, a MFL sensor head prototype composed of two permanent magnets and eight hall sensors was designed and fabricated. A steel cable specimen with several types of damage was inflicted and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. The measured MFL signals were used to interpret the healthy condition of the steel cable. For improving the resolution and quantification of the damage level, digital signal processing techniques were performed. Finally, the measured MFL signals were visualized by using 3D imaging method.

This study presents a technical overview of inspection practices on cable-stayed bridges and suspension bridges in service. Specially, it focuses on special inspections, which are regularly scheduled or unscheduled inspections, contrary to those used in general bridges. Conceptual improvements of special inspections are discussed.