LACONIA — Officials of the New Hampshire Department of Transportation (DOT) outlined two plans for reconstructing the bridge where Rte. 3 crosses the old Boston & Maine railway line at Weirs Beach — one that would close the bridge and complete the job in a month and another that would keep one lane open and complete the job in four months — to a group of local officials and business business owners gathered at City Hall on Tuesday night.
The bridge dates from the 1890s when the split stone abutments were built and the concrete slab was added when the bridge opened in 1933. It was added to the so-called Red List of failing bridges in 2009, currently ranks 40th on the DOT's bridge priority list and is scheduled to be rebuilt in 2020. Although the bridge has no posted weight restrictions, the deck and superstructure are both rated "poor" and the abutments are rated "fair". A traffic count in 2011 found that the bridge carried a average of 13,000 vehicles — five percent of them trucks — daily during the summer season.
John Sargent, a design engineer at the DOT, said that the location of the bridge in the center of the Weirs and its place in the regional traffic network posed challenges for the project. He explained that if the bridge is closed to through-traffic during construction, traffic would have to be detoured around an 18.3 mile loop — a half-hour drive — which would mirror the re-routing of traffic when the bridge over the Weirs Channel is occasionally closed to four-wheel vehicles during Motorcycle Week. Consequently, planning a route for emergency vehicles to bypass the bridge is a high priority.
At the same time, Sargent said that if the bridge were kept open to one-lane traffic its proximity to Lakeside Avenue, Channel Lane and private driveways as well as the lack of stacking space for stopped vehicles would require an elaborate signalized intersection. Even then, he expected, there would be significant congestion during the four months of construction. Moreover, phasing construction over four months would add an estimated 25 percent to the cost of the project.
Bob Durfee, an engineer with Dubois & King who has worked at Weirs Beach, called closing the bridge "a non-starter" because of the volume of traffic flowing along Rte. 3 throughout the year. However, others agreed with the man who said "four months would be far too long for businesses" and urged the DOT to build the bridge "as quickly as possible."
Sargent said that closing the bridge would require detouring traffic and finding a by pass for emergency vehicles was a priority. He suggested it might be possible to route traffic along Channel Lane to an unimproved private right-of-way that runs north of the Paugus Bay Campground and connects with Hillard Road. He said while the road would be passable by ambulances and cruisers it would require some improvements to carry larger vehicles like ladder trucks.
Alternatively, Jeff Thurston of Thurston Marine said that the firm has an easement to cross from its property to the Weirs Beach Drive-In Theater, which is owned by Patricia Baldi, and access Rte. 3 beneath the marquee, which might also provide a bypass. "The toll we would charge would be minimal," he quipped.
The timing of the construction, which should avoid both the summer traffic and the winter weather, also presents a challenge, Sargent said. "March is the best roll of the dice," Thurston remarked.
Mark Richardson, administrator of the Bureau of Bridge Design at DOT, said that there is $1.5 million for the project allocated in the Ten-Year Highway Plan. He anticipated the design and engineering would be completed in time to solicit bids in 2019 and undertake construction in 2020.