The accelerated construction technology that received praise for quickly replacing 14 bridges over Interstate-93 in Medford will be used to replace the North Main Street bridge near downtown Andover.
Built in 1929, the railroad overpass is one of the town’s busiest bridges. Carrying Route 28 traffic over the Andover commuter railroad tracks, the bridge connects downtown Andover to Shawsheen Square. The bridge is just north of the Public Safety Center and south of McDonald’s on Route 28.
Work could begin in the spring of 2014 and be completed by the end of 2014.
Officials with the state’s Department of Transportation last week presented their plan to replace the bridge at a public hearing last week, following six years of discussion and development.
The project will replace the bridge’s entire superstructure — the steel and concrete that cars drive over, according to John Watters, an engineer on the project. It will also replace parts of the bridge’s substructure — the walls underneath the bridge that support it.
The latest estimates put the project at around $3.4 million, which will be paid for by the state, according to Watters. Construction will start sometime in 2014 after it goes out to bid. With work beginning next March, an aggressive schedule could have it completed by the end of the 2014 calendar year, Watters said.
To do the work, the road will be reduced to two 10-foot lanes, one in each direction of travel, with one 4-foot-wide sidewalk, according to Matt Hopkinson, DOT project manager. One half of the bridge will be replaced at a time, with traffic travelling on the side of the bridge not being replaced.
To do this as quickly as possible, the state will put the steel and concrete together off-site and then fit the pieces together in Andover like “really big Legos,” according to Watters.