Traditional infrared thermography surveys of bridge decks have been carried out at low speed (< 10 mph). In recent years the cameras have improved, and this, along with the DOT’s push to eliminate closures, has encouraged agencies to solicit, and providers to conduct, highway speed infrared surveys. To evaluate the tradeoffs between the traditional low-speed vs. highway speed infrared, an investigation has been carried out to quantify the effect of speed on the resulting infrared images, and to evaluate the influence of speed on the final analysis. Infrared data has been collected on several bridge decks at speeds ranging from 10 to 40 mph, and the resulting infrared images have been compared and evaluated. The results show that, while the higher speeds create some blur, the obvious infrared delamination anomalies can still be detected, whereas the subtler anomalies with lower temperature differentials might not be as accurately characterized. In terms of ultimate application, this study shows that highway speed infrared is a viable approach for overall condition assessment, prioritization, and scoping, while low speed infrared is preferable where the data is to be used at a project level to determine actual removal areas.

Related Publications