Few can argue that the U.S. does not have a problem with structurally deficient bridges. All they have to do is look at the tragic collapse of the I-35W bridge, which claimed 13 lives in August 2007 in Minneapolis.
The author of a “white paper” on emerging inspection technology is confident that an argument can be made about the exact number of bridges being classified as deficient and what to do about them.
Peter Vanderzee is the president and CEO of Lifespan Technologies, a company that develops sensory technology, which he hopes will help engineers predict and avoid tragedies like the Minneapolis collapse. Vanderzee says up to 40 percent of bridges classified as “structurally deficient” may be misdiagnosed based on the current method of inspection.
“The problem as it’s understood in Washington, DC, today is not well defined,” Vanderzee told Land Line on Monday, Nov. 24.
“That’s principally caused by the fact that the federal government and the states use a 37-year-old visual inspection protocol to determine the condition of the bridges across the country.”
Vanderzee says visual inspections and written reports can vary from inspector to inspector and may lead to unnecessary weight restrictions being placed on bridges.
Federal Highway Administration officials said in 2006 that the U.S. had more than 73,700 structurally deficient bridges. Recent estimates put the number at about 77,000.
Vanderzee believes sensory technology can someday replace the 37-year-old “status quo” method of inspecting bridges, and that could benefit truckers who have to bear the brunt of load limits and detours.
For a price much lower than full-on rehabilitation or replacement, Vanderzee believes a vast number of bridges can be shored up and have their weight limits increased.
“Anytime a load posting is removed and detours are removed, the truckers can take more direct routes and save money,” Vanderzee said.
“If a bridge is posted and there’s a detour that is required, or it’s structurally deficient, we think the use of better technology would be employed at that point, and then the owners can understand the real problems with their structure and take action.”
Members of Congress are already looking for solutions to the bridge problem and are likely to incorporate some sort of technology-driven inspection process into the next large-scale transportation funding package due to be written in 2009.
U.S. Rep. James Oberstar, D-MN, who chairs the House Transportation and Infrastructure Committee, introduced a bill in 2007 in response to the Minneapolis collapse. The bill called for employing technology to sense changes in bridge structures and give engineers a better idea about when it’s time to shut the bridge down for repair or replacement.
Oberstar’s bill stalled in the Senate as the 110th Congress broke for the fall elections.
The next Congress will have to start over again with any bills that did not make the cut by the end of the 110th session, said Mike Joyce, legislative affairs director for the Owner-Operator Independent Drivers Association.
“The likelihood is pretty high that the new Congress will take up a bridge bill,” Joyce said. “Does it become part of the reauthorization bill? Likely.”
Joyce has met Vanderzee and has read the white paper titled “A Better Way to Fix Our National Bridge Problem.”
“It’s certainly something that we’ve advocated for,” Joyce said. “We would like to see a better analysis and a better use of technology when it comes to the maintenance of our roads and bridges, and technology like his offers some of those solutions.”
Vanderzee recently presented his paper to Federal Highway Administrator Tom Madison and submitted it to Oberstar’s committee as testimony on the issue of road and bridge funding.
Vanderzee’s technological solution is a small sensor that detects the slightest change in bridge characteristics. It supplies data that engineers can analyze in a quantitative manner, rather than rely on subjective reports.
Vanderzee tested the technology on 10 short-span bridges selected by the Georgia Department of Transportation because they had weight restrictions or were candidates for costly replacement.
“Two of the 10 bridges tested did not need weight restrictions,” Vanderzee said. “Another two could have increased load-bearing weight with minimal costs between $10,000 and $40,000.”
Vanderzee said if that formula were used in other states, somewhere between 20 percent and 40 percent of structurally deficient bridges could be reclassified or shored up for minimal cost.
“If that’s true, we’re using way too much diesel fuel,” he said. “Truckers are spending way too much money. They could get more done in less time if the state DOTs and counties and others that own these bridges would implement better technology.”
– By David Tanner, staff writer