August 3, 2007
Contact: Meg Mincolla
Phone: (775) 888-7172
Nevada Bridges Named Nation's Best
Following the tragic collapse of Minnesota's I-35W bridge, the Nevada Department of Transportation joins the nation in extending sympathies to all those affected, and will continue an aggressive bridge inspection and rehabilitation program that has led Nevada bridges to be named the nation's best.
"We extend our heartfelt sympathy to all of those affected by the tragic Minnesota bridge collapse, and I have personally been in contact with the Minnesota Department of Transportation to offer any services that may be needed," NDOT Director Susan Martinovich said. "In Nevada, as throughout the nation, safety is our primary focus. The Nevada Department of Transportation will continue the extensive bridge program that has led our bridges to be named the nation's best."
The Nevada Department of Transportation inspects all bridges in the state of Nevada, including city and county-maintained structures, and spent $24.3 million for bridge rehabilitation, replacement and seismic retrofitting during fiscal years 2005 and 2006. All bridge structures are inspected every two years, while bridges with more extensive deterioration are inspected more often.
"Bridges showing any type of issues with structural integrity are prioritized first for rehabilitation," NDOT Chief Bridge Engineer Mark Elicegui said.
In late 2006, Nevada was recognized as having the nation's top bridges by a Better Roads magazine survey. Ranking bridge condition through October 2006, the survey shows only four percent of Nevada's approximately 1,800 state, county and city bridges being functionally obsolete or structurally deficient, compared to a national average of 25 percent. Arizona came in second with the only other single-digit rating at five percent.
Using Federal Highway Administration (FHWA) classifications, the survey defines structurally deficient bridges as those that are closed, restricted to light vehicles or require immediate rehabilitation. Functionally obsolete bridges are deficient in carrying capacity, clearance or alignment with the roadway. The term "deficient bridge" is used to describe bridges in need of major rehabilitation or even replacement. It does not mean the bridge is in danger of collapse.
NEVADA BRIDGE FACTS AT A GLANCE
∙ Nevada has close to 1,800 bridges. Approximately 1,050 of those bridges are under the direct responsibility of NDOT, with the remainder being under the jurisdiction of local governments.
∙ During fiscal years 2005 and 2006, NDOT spent $24.3 million for bridge rehabilitation, replacement and seismic retrofitting.
∙ The Nevada Department of Transportation has an aggressive bridge inspection and maintenance program.
∙ All NDOT and consultant bridge inspectors are trained to federal standards. These professional inspectors thoroughly review all elements of each bridge to evaluate condition, and assign ratings to the bridge deck, superstructure and supporting substructure elements.
∙ Minor bridge repairs are often performed immediately during bridge inspection in order to avoid any delays that could allow deterioration to worsen.
∙ To preserve Nevada's public bridges in good condition, the Nevada Department of Transportation prioritizes any necessary bridge repairs in the following order: 1) Replace or rehabilitate structurally deficient bridges before they become hazardous or overly burdensome to users. 2) Replace or rehabilitate functionally obsolete bridges before they become hazardous or overly burdensome to users. 3) Seismically retrofit bridges that do not meet current seismic standards. 4) Apply timely repairs to existing structures.
∙ Nevada has the lowest percentage of bridges of any state categorized as structurally deficient or functionally obsolete. Approximately 70 Nevada bridges (nearly four percent of all Nevada bridges) qualify for federal funding as structurally deficient or functionally obsolete bridges. The structurally deficient and functionally obsolete categories do not indicate that bridges are in danger or cannot meet the needs of the public. Instead, these categories indicate structures that are a priority for corrective measures and may be restricted to certain vehicle use, such as overweight and over dimensional vehicles. Many of Nevada's functionally obsolete bridges are so categorized due to roadway widths either on or under the bridge that are lower than desirable, and not due to any deficiencies in structural integrity.
∙ Minnesota's I-35W Bridge was a deck-truss bridge structure. Nevada has only one deck-truss bridge structure, located on U.S. 93 over Meadow Valley Wash in Caliente. This structure has four truss lines, providing additional redundancy and support, while the structure that failed in Minnesota had two truss lines.
∙ Earthquake preparedness is vital in the seismically-active state of Nevada. NDOT has replaced or seismically-retrofitted 81 bridge structures at a cost of over $27 million since seismic prioritization began in the early 1990s.
