Engineers Swarm on U.S. Bridges To Check for Flaws
 AP A decade ago, the I-90 bridge near Cleveland sagged when gussets buckled. |
Bridge inspectors fanned out across the U.S in mid-August, crawling over structures on deficiency lists and paying particular attention to ones with designs similar to the steel deck truss and gusseted connections of Minneapolis’s Interstate-35W crossing. They announced a few findings, but they and the politicians and local journalists tracking them made a lot of connections and raised many reminders about defrayed maintenance and delayed replacement projects everywhere.
Meanwhile, in Minnesota, planners pushed ahead to have a replacement bridge constructed rapidly, although they quickly ran into conflicts over potential enhancements such as adding light rail and more lanes. The Minnesota Dept. of Transportation on Aug. 14 whipped out a preliminary design to solicit feedback. It features a 10-lane bridge with four shoulders, allowing room for expansion. The old bridge started as a six-lane crossing and later was expanded to eight by claiming most of the shoulders. The proposed alignment appears to match the old one.
Bob McFarlin, assistant MNDOT commissioner says “betterments” will be heavily discussed, with some “reasonable accommodating” for increased traffic projections. Speed will be a cost “wild card” but the goal is a 100-year service life, he says.
MNDOT says five teams or firms have qualified to bid, although it does not say which ones actually are bidding. The prequalified teams are:
MNDOT says it expects cost of the replacement to exceed $150 million. But Charlie Humphries, vice president of business development for Johnson Bros., says estimates are premature. “We need to get more parameters,” he says.
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In an Aug. 10 letter to Minnesota Lt. Gov. Carol Molnau, Federal Highway Administration Division Administrator Thomas K. Sorel said that the agency’s Emergency Relief program provides for repair and restoration of highway facilities to pre-disaster conditions. “ER funds are not intended for new construction to increase capacity, correct non-disaster related deficiencies, or otherwise improve highway facilities,” Sorel said. Features beyond pre-disaster conditions “would need to be reviewed and approved by FHWA,” he says.
Inspectors around the country visited many deficient structures that have languished for decades. And some proposed repair or replacement projects found new life, such as replacement of New York’s 52-year-old Tappan Zee bridge across the Hudson River between Nyack and Tarrytown, and replacement of New Jersey’s 75-year-old, three-mile-long Pulaski Skyway. Both are non-redundant, steel deck-truss structures.
According to FHWA, there are 756 steel deck-truss bridges in the U.S. Ohio tops its list with 187, but Ohio DOT says most of the ones on FHWA’s list are of designs different from the Minneapolis bridge that failed. Pennsylvania DOT said on Aug. 3 that it would reinspect the state’s 54 steel deck-truss bridges by the end of November. Transportation Secretary Allen Biehler says PennDOT is using its 100 bridge inspectors, as well as tapping state engineering firms.
Discoveries are being made, although some reports are dribbling out in local press accounts, rather than DOT announcements. The Lowell Sun, in Lowell, Mass., says the new inspections led to the closure of one of four lanes of a deck-truss bridge in Lowell on Aug. 12. The paper reported inspectors found support beams of the Textile Memorial Bridge had deteriorated faster than expected since the last inspection. But Jeffrey Gomes, an engineer with the city’s Planning & Development Dept., says the lane closure was simply to let HNTB, the Massachusetts Highway Dept.’s...
