Unmanned Aerial Systems (UAS) continue to grow in both popularity and utility within the national airspace system. The use of commercial UAS for civil inspection, specifically that of bridge structures, is becoming commonplace among practitioners and academics alike. The development of an integrated bridge-inspection hazard model provides a way for UAS operators to prepare for and respond to changing environmental conditions that could otherwise prevent a successful UAS flight. The interaction of wind-induced airflow with bridge surfaces creates an aerodynamic wake that can result in hazardous conditions for a UAS platform operating in close proximity. An analysis of this airflow surrounding an overpass bridge using computational fluid dynamic (CFD) models shows where these hazardous areas exist, based on initial wind conditions, existing functionality of UAS platforms, and mitigating systems that exist within current UAS technology. Altering the initial conditions by modifying wind velocities allows for a baseline understanding of which areas surrounding an overpass bridge structure are not suitable for successful UAS flight. Hazard zones range from severe, moderate, and mild, to no appreciable hazard. Moderate to extreme hazard zones are located in areas where high levels of wind shear, vorticity, or general turbulence exist, making UAS operations difficult. This study develops a practical model that may be utilized by UAS operators to better understand and potentially avoid unsafe flight environments during bridge structure inspections.



This research was partially funded by FHWA Transportation Pooled Fund Study TPF-5(387). The lead agency is the Indiana Department of Transportation. Partner agencies are Caltrans, DelDOT, GDOT, IDOT, MDOT, MnDOT, PennDOT, UDOT, and VDOT.


The authors confirm contribution to the paper as follows: study conception and design: John H Mott; data collection: Jack J. Green; analysis and interpretation of results: Jack J. Green; draft manuscript preparation: Jack J. Green, John H. Mott. All authors reviewed the results and approved the final version of the manuscript.