by: Keith Nichols, PE, Senior Transportation Engineer
The recent collapse of the I-5 Skagit River Bridge in Washington highlights the importance of bridges to the regional transportation system and concerns about bridge conditions and funding.
Bridges are a prominent part of the Hampton Roads landscape. Major spans such as the Coleman Bridge, James River Bridge, and High Rise Bridge connect distinct areas of the region. Bridges on the Interstate system create a limited access network designed to improve mobility into and throughout the region. Other bridges provide a grade separation that allows traffic to cross major intersections without stopping. And smaller structures such as culverts span the myriad of creeks, swamps, and waterways in our region. These crossings combine to total 1,226 bridges throughout Hampton Roads.
Hampton Roads has longer bridges than many other areas. Looking at 35 comparable metropolitan areas throughout the U.S. with populations between one and three million people, Hampton Roads has the second longest average bridge length behind only New Orleans. The total deck area of bridges in Hampton Roads is also high, ranking 8th highest among the 35 comparable metropolitan areas. Since bridges are much more expensive to build and maintain than typical roadways, this means that Hampton Roads needs higher funding levels to maintain these structures.
Aging bridges are a concern both in Hampton Roads and throughout the country. The median bridge age in Hampton Roads is 38 years, slightly younger than the national median age of 40 years. However, one out of every six bridges in Hampton Roads was built prior to 1960.
As these bridges age, their condition becomes as issue. Bridges with elements that need to be more closely monitored and/or repaired are classified as structurally deficient. As of May 2013, a total of 80 bridges in Hampton Roads are classified as structurally deficient, up from 54 bridges in August 2007.
With so many bridges in Hampton Roads and the median age of bridges expected to increase, the amount needed in future years to sustain bridge connections is high. It is estimated that it will cost $8 billion over the study period of the upcoming 2040 Hampton Roads Long-Range Transportation Plan (2016-2040) to sustain existing bridge connections in the region. This amount exceeds the $7.3 billion cost of all the construction projects that were included in the 2034 Hampton Roads Long-Range Transportation Plan.