A new report from the American Road and Transportation Builders Association (ARTBA) shows that 54,259 of the USA’s 612,677 bridges are rated as ‘structurally deficient’, with the country’s drivers crossing this damaged infrastructure 174 million times daily.
According to ARTBA’s analysis of the US Department of Transportation’s (USDOT) just-released 2017 National Bridge Inventory database, 8.8% of the USA’s bridges are rated as structurally deficient, totaling 1,216 miles (1,957km) of compromised infrastructure.
The nearly 48,000-mile (77,248km) Interstate Highway System (IHS) carries 75% of the country’s heavy truck traffic, with the study showing that on average there is the equivalent of one structurally deficient-rated bridge for every 27 miles (43km) of the major freight network. The 1,800 structurally deficient Interstate bridges are crossed 60 million times daily.
The research also revealed:
• The average age of a structurally deficient bridge is 67 years, compared to 40 years for non-deficient bridges;
• One in three (226,837) US bridges have identified repair needs;
• One in three (17,726) Interstate highway bridges have identified repair needs.
To help ensure public safety, bridge decks and support structures are regularly inspected for deterioration and remedial action. They are rated on a scale of zero to nine, with nine meaning the bridge is in ‘excellent’ condition.
A bridge is classified as ‘structurally deficient’ and in need of repair if the rating on a key structural element is four or below. While these bridges may not be imminently unsafe, they are in need of attention.
Other key findings in the ARTBA analysis:
• Iowa (5,067), Pennsylvania (4,173), Oklahoma (3,234), Missouri (3,086), Illinois (2,303), Nebraska (2,258), Kansas (2,115), Mississippi (2,008), North Carolina (1,854) and New York (1,834) have the most structurally deficient bridges;
• The District of Columbia (8), Nevada (31), Delaware (39), Hawaii (66) and Utah (87) have the least;
• At least 15% of the bridges in six states – Rhode Island (23%), Iowa (21%), West Virginia (19%), South Dakota (19%), Pennsylvania (18%) and Nebraska (15%) – fall in the structurally deficient category.
“At the current pace of repair or replacement, it would take 37 years to remedy all of the nation’s inventory of structurally deficient bridges,” said Dr Alison Premo Black, the chief economist for ARTBA, who conducted the analysis.
“A new infrastructure package aimed at modernizing the Interstate System would have both short- and long-term positive effects on the US economy.”