Bridge Inspections with Small Unmanned Aircraft Systems: Case Studies

Bridge inspections are important to proactively ensure that structures are safe for use by the traveling public. Accessibility challenges during inspections often necessitate the use of special equipment, such as underbridge inspection vehicles (UBIVs), which impact both cost and risk of inspections. The objective of this research is to develop and demonstrate a small unmanned aircraft system (sUAS) that can be used to perform bridge inspections that would typically require the use of a UBIV. The sUAS used for this project uses a laser range finder and an optical flow sensor to assist with obstacle avoidance in the GPS-restricted area underneath bridges. This paper provides an account of several demonstration sUAS bridge inspections with an emphasis on incorporating an sUAS into current inspection practices, including a discussion of the advantages and ongoing challenges. Recommended applications for sUAS bridge inspections are provided, including periodically replacing the use of a UBIV for routine inspections of bridges in good condition and inspecting structures with load restrictions, especially post-impact, which may prohibit the use of a UBIV. (c) 2019 American Society of Civil Engineers.