Rough Roads:Part 2, Deteriorating Bridges

Print More

(Host) Vermont’s bridges need work – lots of work.

Much of the reason simply has to do with age. Hundreds of bridges built after the Great Flood of 1927 are at the end of their useful life. Many of the bridges on the interstate that were built in the 1950s and 60s also need major repair.

But despite a large increase in spending, the state is still catching up to the work that’s needed.

VPR’s John Dillon takes us on a tour of bridges, in this second part of our Rough Roads series.

(Road noise, clanks and rumbles of cars)

(Dillon) This is the story of three bridges – structures that in many ways are typical of Vermont’s extensive network of river and road crossings.

First, let’s take a walk across the Winooski River on the Taylor Street Bridge in Montpelier. Our guide is city manager Bill Fraser.

(Fraser) “I’m not exactly sure how old this bridge is. I know it was part of a series of bridges that were rebuilt throughout Vermont after the 1927, so it’s probably circa 1929 era – that vintage.”

(Dillon) The steel truss bridge used to be green. But like some of the cars that cross it, years of travel and road salt have left it rusty and decrepit-looking. The Taylor Street Bridge, like 260 other town bridges around Vermont, is listed as “structurally deficient.” That doesn’t mean it’s about to fall into the river. But, as Fraser says, it does need major work.

(Fraser) “It’s an old bridge. It’s had a lot of years of maintenance. Some of it’s just surface rust. That can be handled by sanding and painting. Other parts of it are structural members underneath and differen supporting members up above are weakening. It’s certainly in no immediate danger but it needs a complete rehab to last another 75 years.”

(Dillon) The good news is that the bridge will be rebuilt from the abutments up. The state and the federal government will pay all the cost under a program that preserves historic bridges.

The bridge was included in the program more than five years ago. But the overhaul is probably at least another five years away. Fraser would like the work done sooner.

(Fraser) “We’d like to not be worried about the annual inspection and interim repairs. Obviously as we can see by standing here it really is due for some maintenance work, and the longer we delay that the worse off we are.”

(Dillon) Despite a 36% increase in new spending for bridge work, the state is still catching up with the amount of work that’s needed.

That’s true for state and town bridges, and for spans on the interstate system.

(Sounds of footsteps)

(Dillon) On a cool, cloudy day last week, Mike Hedges checks out a bridge near the Interstate 89 exit in Middlesex.

(Hedges) “You can see where the concrete has deteriorated and the seal is gone and that will have to be replaced fairly soon.”

(Whoosh of cars going by)

(Dillon) Hedges is head of the structures division at the Agency of Transportation. He loans me an orange safety vest before we take the top to bottom bridge tour.

Underneath the structure, Hedges points out where the concrete supports – called piers – are starting to show wear.

(Hedges) “You can see some of the deterioration of the pier caps here where the joints from above have leaked over time and salt is deteriorating the concrete and reinforcing steel that’s now obvious.”

(Dillon) A report prepared by the state’s joint fiscal office says there’s a big bill coming due for bridge work around Vermont. Bridges last a long time – about 80 years. But the 1927 generation is overdue to be replaced. And the interstate bridge system built in the 1950s and 60s now also needs major work.

The report says 60% of the state and town bridges longer than 20 feet should be replaced or rebuilt over the next 10 years.

Mike Hedges sees the problem first hand.

(Hedges) “Timing definitely has something to do with our problems here. With the interstate anyway they were all constructed at about the same time, so they are coming due for at least rehabilitation.”

(Dillon) The Legislature has recognized the problem and allocated an additional $18 million for bridge work. Thirteen percent of the long bridges on the interstate are structurally deficient. The goal is to reduce that to 7%. But Hedges says there’s still work to do.

(Hedges) “That’s going to be difficult even with current funding levels. These are goals that we’ve set and over the long term we’re going to try to reach them.”

(Dillon) Some bridges are just too far gone to replace.

(Sounds of bird songs)

(Dillon) Just down the road by the Middlesex exit, an old steel truss bridge spans the Winooski. It’s much quieter here than up by the big highway.

From down by the water you can see that the concrete piers have crumbled away exposing the steel supports inside. This bridge was closed for repairs last year, and it will be replaced in the next few years.

(Hedges) “There could have been a lot of work done to these structures in the past. But inherently these old trusses with the exposed steel are prone to corrosion. They were not designed for the heavy loads we’re now seeing on the highways. And most of them are all used up.”

(Dillon) The last bridge on our tour is a mile or so upstream. The concrete and steel structure was built in 2002 and Hedges likes what he sees.

Although the beams look rusty, Hedges says that’s intentional. The metal is supposed to get a thin layer of rust and the corrosion won’t penetrate deeper. The bridge was designed with features that keep water and salt away from critical areas.

(Hedges) “We’ve done a number of things to try to preserve it here. You can see where the ends of the beams were painted and then greased in this area to try to hold off the corrosion that you usually see near these joints. And the joints has one of those troughs and it appears to be working well

(Dillon) With proper maintenance, Hedges says this bridge should last 80 years.

For Vermont Public Radio, I’m John Dillon in Montpelier near the Winooski River in Middlesex.

Note: Tomorrow in our Rough Roads series, VPR’s Steve Zind spends the day with the highway crew in Randolph.

Comments are closed.