(Host) Following the catastrophic collapse of a bridge in Minneapolis, officials here sought to assure the public today that the bridges in Vermont are safe.
The officials also said that four bridges on the Vermont interstate system are the same design as the one that failed in Minneapolis.
So the state said that it would once again put a new focus on bridge repairs.
VPR’s John Dillon reports.
(Dillon) Transportation Secretary Neale Lunderville stood near a 79-year-old bridge in Moretown. The bridge is considered structurally deficient and it’s a glaring example of the state’s aging transportation infrastructure.
Lunderville says safety is the state’s top concern.
(Lunderville) "The bridges that we deem to be structurally deficient are inspected more regularly as often as they’re needed, at least once a year, and even more often, by our bridge inspection teams."
(Dillon) About 16% of Vermont’s bridges are structurally deficient. That’s the 9th worst ranking in the nation. The bridge collapse in Minnesota has focused attention on bridge safety. But only 8.4% of its bridges are structurally deficient.
The Interstate 35 bridge that collapsed into the Mississippi River is a deck truss structure. That means the bridge is supported at either end, and the load is carried by a truss built underneath.
It’s a common bridge design. But there’s little redundancy built in. Richard Tetreault, Vermont’s chief transportation engineer, says the bridges are called fracture critical structures.
That means if one part of the structure fails, the entire bridge could collapse.
(Tetreault) "For example this truss back here that was built after the flood of ’27 is a non redundant structure. You have two trusses, and the bottom cord of the truss is facture critical. If it were to fail the whole bridge would probably come down and that’s what a deck truss is similar."
(Dillon) Vermont has eight deck trusses. Seven are on the state’s list of structurally deficient bridges. Three are on Interstate 91 north and south in Rockingham and Brattleboro.
But Lunderville says just because a bridge is structurally deficient, it’s not in imminent danger of collapse.
(Lunderville) "But what it does mean is that we have to take steps to make them safe for any load that goes over it. A structurally deficient bridge is one that you see that has a load rating. They’re load limited to certain loads. They may be limited to one lane. Or in some cases, they may actually be closed."
(Dillon) The problem is getting worse even as the state tries to spend more on bridge repair. The
number of structurally deficient bridges on the interstates grew from 35 in 2003 to 40 in 2006. On state roads, deficient bridges went from 148 in 2003 to 157 last year.
The state has launched a plan called the Road to Affordability in an attempt to catch up with the growing repair list.
(Lunderville) "This is exactly what we recognized in the Road to Affordability. We have to realign our priorities around system preservation."
(Dillon) The Road to Affordability is the latest of several plans to improve Vermont’s transportation network. In 1988, Governor Madeleine Kunin proposed Bridge 2000, a plan designed to spend over a billion dollars to get bridges and roads in for the next century. It didn’t happen.
A few years later, Glenn Gershaneck was Governor Howard Dean’s transportation secretary. He wrote a plan called You Can’t Get There from Here that called for more spending on infrastructure.
Gershaneck says there’s was then — and is now — too much competition for projects.
(Gershaneck) "The capacity to produce all of these separate programs often exceeds the capacity of the staff and the resources."
(Dillon) There are also issues of geography and history. Vermont is a place with lots of rivers, streams -and bridges. And many of the bridges are nearing 80-years-old because they were replaced after the Great Flood of 1927.
For VPR News, I’m John Dillon in Montpelier.