The Federal Highway Administration (FHWA) recently issued a proposal to the National Bridge Inspection Standards (NBIS) that would improve oversight of U.S. bridge inspections.
The FHWA proposal addresses requirements set by the Moving Ahead for Progress in the 21st Century Act (MAP-21). Offering states the varying inspection methods in determining inspection intervals for bridges, each state can have the option to continue their current inspection intervals (Method 1) if they determine the requirement is satisfactory, or choose to instate more rigorous requirements for inspectors, as depicted in Method 2. This method would call for bridge specialists to assess potential risks to the point of failure for each individual bridge, or a cluster of bridges, to be further evaluated by experts. Current standards set inspection intervals at roughly 24 months apart with a maximum interval being 48 months. Bridges with higher risk considerations are inspected every 12 months. While Method 1 consists of similar regulations, it does differ by requiring more thorough criteria for establishing which bridges need 12-month intervals for inspections.The Federal Register notice says that Method 2 “involves the identification and use of an interval that is commensurate with the risk of safety of service loss in a given bridge.” Inspectors could determine the risk factors based on what is described as an “impact and consequence matrix,” serving as a formula for assessing failure probability.
The last update to NBIS regulations was set in 2009. The FHWA proposal applies to highway bridges on all public roads, on and off federal-aid highways that include tribally and federally owned bridges, and privately owned bridges that connect to public roads.
According to the American Road and Transportation Builders Association (ARTBA) 2018 Bridge Report, 47,052 out of the nation’s 616,087, or 7.6%, bridges are rated “structurally deficient” and need urgent repairs. In 2016, 56,007 out of the nation’s 614,387, or 9.1%, of our bridges were rated structurally deficient. The 2017 Infrastructure Report Card noted the trend that the number of structurally deficient bridges was decreasing steadily.
Ultimately, this effort is directed to improve the safety and quality of our bridges, especially with the new technological advances in bridge inspection. In ASCE’s 2017 Infrastructure Report Card, our nation’s bridges earned the grade of a “C+,” and we must continue to find solutions to ensure our nation’s surface transportation network is a safe and reliable network. ASCE’s government relations team will provide comments, which are due January 13, 2020.