EAST MIDDLEBURY — The Sand Hill Bridge is on schedule to be replaced during the spring of 2014 at a cost of more than $2 million in a project that will close Route 125 through East Middlebury for 40 days.
That was the word on Monday from Vermont Agency of Transportation (VTrans) officials and representatives from the engineering firm of Vanasse Hangen Brustlin Inc. (VHB), who were on hand to explain the span replacement plan to around 25 people at a meeting at the East Middlebury United Methodist Church.
Project details are being closely monitored by East Middlebury residents, who are concerned about the impact the work might have on the Middlebury Gorge swimming hole, surrounding trees and vegetation, and traffic. The Sand Hill Bridge, erected in 1924, spans the Middlebury River over scenic Route 125, a busy road leading to Ripton, the Middlebury College Bread Loaf campus, the Snow Bowl and Route 100 in Hancock.
Chris Goodrich, lead engineer for VHB, told residents the new bridge will mimic the historic nature of the current span while providing wider passage for vehicles and pedestrians.
The current bridge is 20-feet, 6-inches wide from curb to curb, with no sidewalk. The new bridge would have a width of 36 feet, with 11-foot lanes, a 4-foot shoulder on the upstream side and a 3-foot shoulder with sidewalk on the downstream side.
While previous project designs attempted to straighten out the pronounced curve of Route 125 in which the span is located, Goodrich explained that the final design does not.
“We are basically staying on the existing alignment,” Goodrich said.
Still, the new span will result in the centerline of Route 125 shifting to the east by around 6 feet. It is an alignment that Goodrich said will not result in any impacts to the gorge, archaeological resources (like the nearby historic ironworks) and the slope along the north side of Route 125.
When construction begins next spring, Goodrich believes work crews will probably erect a temporary platform under the bridge and slice the span into sections that will be lifted out and taken away. The platform would provide insurance against any chunks falling into the Middlebury River below.
“They won’t be dropping (the bridge) into the gorge,” Goodrich stressed.
The structure will be replaced by a pre-cast NEXT (Northeast Extreme Tee) beam bridge over a pre-cast concrete arch, according to Goodrich. It will have railing for extra pedestrian safety.
“It will look like the existing bridge,” he said of the basic design.
But the new structure will handle the daily pounding of traffic somewhat differently than the current bridge, which relies a lot on its arch to absorb the weight load.
“The actual bridge will be supported by rock, similar to what’s out there now, but we didn’t really want to attract the load right next to the gorge, so what we are doing is setting the footings back away from the walls of the gorge,” Goodrich said. “The arch itself will be very close to where the existing arch is, but that is effectively going to be non-load bearing. It is just going to support its own weight.”
With the new bridge, the arch will be largely an aesthetic homage to its predecessor.
In fact, a substantial portion of the bridge structure below the deck will be hollow concrete. It will feature a locked door through which state inspectors will be able to access the interior of the span to check it out from time to time.
Since the bridge components will be pre-cast, this will allow for the structure to be assembled within relatively short order. In the past, the state has taken one or two years to erect new bridges, Goodrich explained. But the increasing use of pre-case bridges allows crews to do the work within a month or two, and in the process eschewing previous project add-ons like temporary spans or phased traffic control. This requires a short-term, complete closure of the road, but a quicker, less costly project.
“Get in, get out; that’s our motto,” Goodrich said.
Drivers can expect Route 125 to be closed for 40 days, noted VTrans Project Manager Jennifer Fitch, though the contractor will have a financial incentive to finish more quickly. Travelers will have to resort to some detours. Out-of-town traffic, including trucks, will need to take Route 7 south into Brandon to pick up Route 73 to get over to Route 100, adding about 18 miles to the driver’s trip.
For area residents and emergency vehicles, the detour will mean using Upper Plains Road and Beaver Pond Road in Salisbury to get from Route 7 to Ripton.
“We will only sign regional detours,” Fitch said. “The town can choose to sign the local detour.”
The state will compensate Middlebury for the wear and tear it experiences on local roads as a result of the detour. Fitch said the town can use that money for whatever it wants, but suggested some of it could be earmarked for police enforcement in the local detour area.
Fitch said she could not guarantee that truckers will use the posted detour to Route 73 versus the local detour. She acknowledged some might just go with the shortest route their GPS systems recommend.
Residents and local officials attending Monday’s meeting seemed generally satisfied with the project design and timetable. Audience questions were brief and primarily aimed at getting details on the scope of the project and how it might affect site visibility for motorists entering and exiting the adjacent North Branch Road. Goodrich said he believed site visibility would be improved for North Branch Road travelers.
The next milestones for the project include:
• Final design ready by April, 2013.
• Bids out by September, 2013.
• Contract awarded by November, 2013.
• Construction to begin during the spring of 2014.
“This is really the best (bridge) we can do in this location,” Fitch said. “I am really excited about it. I think you guys should be excited about it.”
Reporter John Flowers is at firstname.lastname@example.org.