Engineers Await Tragedy's Inevitable Impacts

...Albany and a series of bridges north of Buffalo carrying I-190. Despite this high number of bridges, “we have no indication at this time that we will be pursuing additional funding for the increased cost of these special inspections,” says Carol Breen, NYDOT spokesperson.

South Carolina's DOT replaced the last of its steel arch truss bridges last year. “We're not doing anything differently,” says Lee Floyd, state bridge maintenance engineer for SCDOT. Inspectors will monitor the investigation in Minnesota and make changes as necessary. “For now, it's business as usual.” North Carolina DOT is preparing a report on substandard bridges, due to Secretary Lyndo Tippett in September, says spokesperson Ernie Seneca.

TxDOT

Texas bridges suffer scouring problems

In the Desert Southwest, only a handful of the thousands of bridges in Arizona, Nevada and New Mexico are steel deck truss bridges. All have been inspected in the past two years and will be re-tested in the wake of the Minneapolis collapse, according to officials in each state.

“We have confidence in our inspection process as it stands now,” says Diane D'Angelo, spokesperson for the Arizona Dept. of Transportation, which has jurisdiction over three steel deck truss bridges in the state. “The bottom line is, if any of our engineers had any inkling through their stringent inspections that these bridges were safety problems, they would have been shut down immediately.” Prior to the event in Minneapolis, the state legislature and the governor's office authorized increasing the bridge inspection staff by 50 percent, D'Angelo says. “The advantage that we have here is that we are dealing with a much newer infrastructure, especially in the Phoenix area,” D'Angelo says. “Most of our bridges are fairly new, and we have the advantage of a dry climate.”

Nevada's only steel deck truss bridge, on U.S. 93 over the Meadow Valley Wash, is much shorter and has additional redundancy with four truss lines instead of the two in Minneapolis, according to Marc Grunert, assistant chief bridge engineer with the Nevada Department of Transportation.

“We have an aggressive inspection and maintenance program,” Grunert says. “Even on some of the steel structures where we do see fatigue cracking, we have the ability to actually stop-drill the cracks so that they can't propagate any further, right on the spot. We carry with us the appropriate drills and testing mechanisms to be able to identify those problems, such as magnetic particle testing, ultra-sonic testing or dipenetrant testing.”

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New Mexico has four steel truss bridges, and is currently underway with a multi-billion dollar program to update and modernize the state's highways and bridges. According to the Better Roads National Survey, Nevada and Arizona rank first and second in the nation for having the best bridges. New Mexico ranked twelfth.

California is in the process of reviewing 69 steel deck truss structures in the state, says Lauren Wonder, a spokeswoman in the San Francisco Bay Area office of California's Department of Transportation. The state conducts biennial reviews of all structures, including local bridges. There are none that are scheduled to close and none that of particular concern, Wonder says. California, which already has seismic-related standards, has no plans to change its inspection program and will continue to follow guidelines set by the federal government, she says.

Georgia DOT will inspect two bridges similar to the I-35W bridge, says David Spear, Georgia Dept. of Transportation spokesman. However, both are rated much higher than 50, below which the “structurally deficient” label begins. About 1,100 GDOT bridges are structurally deficient, and it would cost some $2.5 billion to $3 billion to upgrade them, he says. Georgia's highways face a deficit of $7.7 billion over the next six years. Georgia has accelerated its work with public-private partnerships, but “at best, that has limited application,” Spear says.

Major links such as Seattle’s Alaskan Way Viaduct await replacement, but need funding.

Vulnerable
The Minnesota bridge collapse could be the extra nudge Puget Sound area voters need to approve a $17-billion transportation measure in November. It would help fund repairs on some of the state's most vulnerable bridges, including the Alaskan Way Viaduct and Evergreen Point Floating Bridge. “The bridge collapse in Minnesota weighs heavily on people's minds and may help [pass] the funding measure,” says Jugesh Kapur, WSDOT bridge engineer. WSDOT will inspect the 2,945-ft-long Aurora Bridge in Seattle, a steel cantilevered design. “I am satisfied with the completeness of our program,” says Kapur. “Unless Mary Peters instructs us to change something, we will use the same methods.”

Indiana's DOT has identified 13 bridges similar in design to I-35W, but “none are in danger of closing at this point,” according to Andy Dietrick, InDOT spokesman. He adds that the $70 million Indiana gets from the federal government is not adequate for InDOT's “vigorous” inspection program. “We spend another $20 million to $30 million in state funds a year for bridge rehabilitation.”

Schutt

In Virginia, officials are looking at all critical structures, says Malcolm Kerley, VDOT's chief engineer. “I'm sure that as things unfold as to what exactly happened [in Minnesota] there will be proposals for improvements to the program that we will enact.” He adds that VDOT may hire private firms for quality assurance on bridge inspections.

Experts caution against prematurely assigning blame to MNDOT, which has an excellent reputation in the DOT community. STV's Altebrando notes that truss designs have constantly evolved, with codes for welded bridge connections upgraded by the early 70s. “MNDOT is very dedicated. I can't imagine they weren't conscientiously doing their best for this bridge,” he says. “We just have to wait.”

But one lesson to take away is that following federal guidelines is not enough, says William Schutt, president of Doylestown, Pa.-based Matcor Inc. “Feds set guidelines. States follow them and say, ‘we did the right thing,'” he notes. “But a good engineer looks at each individual case, not just applying a checklist.”