Experimental evaluation of unmanned aerial system for measuring bridge movement

Highway bridges are the key element of a transportation system and are essential for transportation of goods, services, and people. They are, however, vulnerable to extreme geologic and hydraulic events such as earthquakes, scour, and hurricanes. It is imperative to collect key perishable data during and after extreme hazard events for engineering evaluation and improving the current and future bridge design and maintenance practices. The objective of the posthazard damage assessment is to collect engineering data related to global structural behavior of different components of a highway bridge such as decks and piers. This paper studies the feasibility of using unmanned aerial systems (UASs) for posthazard damage assessment of highway bridges subjected to extreme geologic and hydraulic hazards through a mock-up test setup. For this purpose, a model bridge was developed to simulate movements of the key components of a highway bridge. Three types of structural movements in bridges have been studied: translation, rotation, and settlement. The results show the capability of the UAS and ground-based tripod assembly with high-resolution camera to detect these movements with high accuracy. The average absolute differences observed between the measured and estimated values were 0.7 cm (0.28 in.), 1 cm (0.39 in.), and 1.4 cm (0.55 in.) in the translation, rotation, and settlement movement experiments, respectively