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CHAPTER 1 Background 1.1 Background The use of uncrewed aircraft systems (UAS) for bridge inspections has increased dramatically in recent years as advances in airframes, sensors, and onboard computing have made UAS more prevalent in the industry. The capabilities of controlled flight and onboard camera systems make UAS an ideal instrument to perform bridge inspections, which typically require visual observation and documentation in locations that are challenging to safely and economically access. Because UAS used for bridge inspections is in various stages of implementation across the country, standards for data collection and evaluation are localized and non-comprehensive. In addition, the specific appli- cation for collection of element-level bridge data has not been thoroughly evaluated, which led to the initiation of this research project. Evaluation and assessment of UAS flight and data collection capabilities to align with the requirements of the AASHTO Manual for Bridge Element Inspection (2019) will provide needed guidance for the standardization of UAS in the bridge inspection industry while ensuring that data fidelity meets the acceptance criteria. 1.2 Research Objectives The main objective of this research was to develop guidelines for implementing UAS into routine bridge inspections with element-level data collection to assist state departments of trans- portation (DOTs) and bridge owners. This main objective included the following four subtasks: ⢠Develop a selection process for UAS technologies, ⢠Develop operator and team qualifications, ⢠Develop a comparison between UAS and conventional element-level inspection methods, and ⢠Develop a stand-alone roadmap for holistic UAS implementation. In meeting these objectives, the research focused on UAS applications during a Routine Inspec- tion to collect comparable, adequate visual data. The inspector is not required to be within armâs length of bridge elements during the code-specified Routine Inspection, but the inspector may require various access methods to document condition states and deficiencies. The intent was to test the efficacy of UAS as a means of access to achieve results similar to past inspections. The terms âRoutine Inspectionâ and âroutine bridge inspectionâ will reflect the National Bridge Inspection Standards (NBIS) definition of a Routine Inspection type throughout this document. 1.3 Organization of the Report Chapter 1 of this final report provides an introduction and overview of the research and report. A literature review with identified knowledge gaps, a description of inspected structures, and the inspection methodology are explained in Chapter 2. The major findings and applications are given in Chapter 3. Finally, the main conclusions and suggested research are discussed in Chapter 4. 3
