Investigating Consistency among Bridge Inspectors Using Simulated Virtual Reality Testbeds

There are more than 623,000 bridges across the United States. Of these, 45% are at least 50 years old, and 6.8% are classified as structurally deficient, indicating a poor condition. The safety and functionality of these structures require periodical inspections and maintenance. Consistent bridge inspection reports are essential to accurately reflect the actual conditions of the bridges. This study examines the consistency of bridge inspection reports for steel and concrete bridges using a virtual reality testbed. A total of 24 bridge inspectors from six districts in Indiana participated, providing condition ratings for bridge decks, superstructures, and substructures in accordance with the 2022 Specifications for the National Bridge Inventory. In addition to numerical condition ratings, inspectors submitted written notes and attached images captured during their virtual inspections. A comprehensive quantitative and qualitative analysis was conducted to assess the consistency of condition ratings, notes, and images taken. Results revealed substantial variability in rating scores, that is, only 30% of inspectors’ assigned ratings precisely matched the expected ratings, with notable variability in ratings for the superstructure of the concrete bridge. This study also examined the correlation between rating performance and demographic factors, such as the inspectors’ years of experience. The results indicated that none of these parameters had a significant correlation with rating accuracy. Moreover, photograph analysis showed that while alignment and elevation views were commonly captured, images of defects were inconsistently captured, particularly for steel bridges. Written notes exhibited further variability, with frequent omissions of defect severity and extent.