Transportation bridge infrastructure asset condition monitoring using uncrewed aerial vehicles (UAVs)

The optimal performance of a road transportation network depends on the serviceability and reliability of bridges connecting the pavements. Bridge performance depends on several geotechnical assets among which abutments play a key role as they support the bridge span, and transfer the vertical and horizontal loads from the superstructure to the foundation. Soil abutments are designed to be stable against overturning and sliding and prevent differential settlement and excessive lateral movements. In the United States, 42 % of bridges are observed to be over 50 years old. Department of Transportation (DOT) agencies periodically monitor and assess the bridge conditions typically every two years. Due to the costs and the time involved in conducting inspections using traditional data collection tools, DOTs are exploring innovative technologies to conduct inspections and realize benefits in terms of access, cost, and safety. They have widely adopted the use of uncrewed aerial vehicles (UAVs) for structural health monitoring of bridges. A few studies also conducted 360⁰ bridge inspections using camera sensors mounted on UAVs in the recent past. In this current study, the US Federal Aviation Administration (FAA) guidelines for commercial use of drones were discussed and followed in field studies. Further, UAVs were demonstrated for conducting 360° bridge inspections and identifying the erosion near abutments using three-dimensional models. This paper presents the application of innovative technologies for geotechnical assessments of two bridges in the Alaska region, with a focus on assessing the need for rehabilitation measures. These new technologies have become essential for reliable condition monitoring post-disaster events as well. This approach is expected to benefit the agencies in managing the transportation geotechnical assets in a timely and cost-effective manner.