RICHMOND, Vt. (AP) - After more than a year of planning using computers, laser levels and measuring devices accurate to a fraction of a millimeter, it took engineers with tape measures and construction workers with sledgehammers to bring the 83-year-old Checkered House Bridge into the 21st century.
On Monday, workers cut the 350-foot U.S. Route 2 bridge in two lengthwise by unbolting the braces holding the trusses together and began the process of pushing the sides apart to widen the span by 12.5 feet.
As far as anyone involved in the project has been able to determine, it's the first time such a technique has been tried on such a large bridge. Officials say the wider bridge is needed to accommodate modern traffic that frequently includes bicyclists, pedestrians and farm equipment. The span is scheduled to reopen in a year.
Workers perch on the structure of the Checkered House Bridge on Monday in Richmond, Vt.
Despite the preparations, the hardest push was the first. After workers moved one 300,000-pound truss about 2 inches downstream on the Winooski River on Monday, crews spent hours trying to free a single spot at the base of the bridge where, despite the specialized rollers it was laid on and pressure from hydraulic jacks, it remained stuck.
"I'm really not surprised. It's such a large structure and such an old structure that there have to be points, friction points, that it hangs up on," said Dale Gozalkowski, of the Albany, N.Y.-based engineer firm Clough Harbour & Associates, who helped design the project and watched Monday as it was put into action.
The original 350-foot Pennsylvania truss bridge was built in 1929, two years after an epic flood washed out a covered bridge in the same spot. The bridges are marked by the crisscrossing I-beams that form a latticework, creating a steel canopy above the road surface.
Vermont Transportation Agency officials have known for decades that the aging bridge about 10 miles east of Burlington needed to be upgraded or replaced. The travel surface was 20 feet wide, barely wide enough for two vehicles to pass each other, and the aging steel and the road surface was deteriorating.
For years, Vermont officials debated the best course of action. They considered tearing it down and building a new one, leaving it alone or turning it into a one-lane bridge and building another alongside it. But the bridge is the last of its kind in Vermont on a major roadway and, as such, is historically significant, said Scott Newman, the historic preservation officer for the Vermont Agency of Transportation.
The total project cost for the bridge and the approaches on both sides is about $16 million. A new open bridge could have been built for about $7 million. But the federal law required that the historic bridge be preserved, if possible, Newman said.