What has the NDDOT done to ensure the safety of N.D. bridges over the past year?

Following the collapse of the 35W Bridge, NDDOT bridge inspectors conducted  an interim safety inspection from August – October 2007. The interim inspection reviewed bridges throughout the state including:

• 751 bridges that were rated structurally deficient, which included 5 urban, 32 state and 714 county bridges.
• In addition, 36 bridges on the North Dakota/Minnesota border over the Red and Boise de Sioux Rivers were inspected through a cooperative effort with Minnesota Department of Transportation officials (MnDOT).
• Inspections were also performed on 137 bridges that were rated fracture critical structures.

During the interim inspection process:

• One bridge on the state system was temporarily closed. The state highway system bridge on US 281 west of Churchs Ferry near Devils Lake was repaired and reopened within weeks
• The NDDOT also worked with county officials to close 19 low traffic volume county bridges to ensure safety of the traveling public.
• NDDOT inspectors also noted that counties had closed an additional 22 bridges as a result of previous inspections

When bridges are closed, local officials work with the state to make corrective repairs, replace the bridge or provide alternative access. The rehabilitation of the county structures is at the county’s discretion, and all repaired bridges are re-inspected prior to opening.

The interim bridge inspection was followed by the regularly scheduled inspection in which 2,436 additional bridges were inspected from November 2007 to April 2008. This inspection included:

• 865 County structures
• 1472 State Structures
• 99 Urban structures

As a result of the regular inspection program for the 2007-2008 inspection cycle, three county bridges were closed (one in Ward County and two in Golden Valley County).

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How does NDDOT ensure its bridges are safe?

The NDDOT has a comprehensive bridge inspection program to ensure bridge safety.. The inspection process includes the review of bridges on a two-year cycle. Following the inspection, the bridge is rated based on a formula generated and developed by the Federal Highway Administration. The data compilation is used to determine and give recommendations about bridges that need to be repaired, replaced or closely monitored.

If a bridge is deemed unsafe, bridge inspectors and engineers have the authority to close a bridge or restrict access. This was the case with the Liberty Memorial Bridge between Bismarck and Mandan in 2006. NDDOT engineers determined that the structure was not safe for traffic and decided to close it down until repairs could be made. After repair work was complete, the bridge was deemed safe and opened to the public. In addition to the regular bi-annual inspection, some bridges may require more frequent or specialty bridge inspections.

NDDOT has an effective bridge rehabilitation and replacement program in which bridge inspection, maintenance, rehabilitation and replacement are a major component of the transportation system.

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What does the bridge inspection rating “structurally deficient” mean?

Over the past year, the term “structurally deficient bridge” has entered everyone’s vocabulary. Although it may sound alarming, it does not mean that a bridge is “unsafe.” The inspection rating review for bridges designates ratings which include Structurally Deficient and Functionally Obsolete.

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Are there some North Dakota bridges rated structurally deficient?

Yes. Some of North Dakota’s bridges and culverts are under the federal engineering classification of structurally deficient, but NDDOT is confident the bridges remain safe because of our frequent inspections and appropriate maintenance actions. Another reflection of NDDOT’s continued emphasis on bridge safety is that North Dakota ranks among the lowest on the entire national highway system in number of structurally deficient bridges. Click here to learn more.

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Are there examples of the bridge program at work in North Dakota?

• Replacement of the Four Bears Bridge near New Town.
• Replacement of US 52 highway/rail overpass at Flaxton.
• U.S. 12 bridge replacement at Scranton.
• Replacement of Main Avenue Bridge over Red River in Fargo.
• New construction of Liberty Memorial Bridge in Bismarck-Mandan to be open for traffic in August 2008.More information on the new Liberty Memorial Bridge construction.
• Construction is currently taking place on 12th Ave. North Bridge in Fargo, and a scheduled completion in 2009. More information on the 12th Ave. Bridge.

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