Much like the house that Jack built, one thing has led to another in the construction project along Interstate 293 in Manchester, NH.
When it was decided that an extra lane was needed to alleviate traffic congestion on the highway running along the southern edge of Manchester, it necessitated a series of other jobs as well.
The highway crosses Brown Avenue and Frontage Road in Manchester, so those two bridges had to be rebuilt as well. And as long as contractors had to do that work, they might as well widen Brown Avenue, also.
“We’re rebuilding the bridges from scratch because the roads needed to be widened,” explained Glenn Cairns, vice president of George Cairns and Sons of Londonderry, NH, the primary contractor for the job.
Congestion caused by heavy traffic en route to the nearby Manchester Municipal Airport necessitated the work. The new lane, which stretches approximately 1 mi. from the Merrimack River to just beyond the Exit 1 bridge at Willow Street (Route 28), will help absorb some of the extra vehicles. When work is finished, three lanes will carry traffic in both directions.
The project also includes the widening of Brown Avenue (Route 3A), which goes underneath the interstate at Exit 2, and leads directly to the airport. A bottleneck has existed on that road for many years because, although it is a four-lane road elsewhere, it narrows to two lanes at the bridge and then widens again on the other side.
The construction will allow the addition of another lane there along with new turn lanes and traffic signals. The changes below the interstate demand that the new bridges over the street will be substantially longer than the original ones.
Traffic going through the construction area on I-293 was moved to the eastbound barrel of the highway on Sept. 4, letting workers focus on the westbound lanes.
Concrete barriers separate eastbound and westbound traffic. The speed limit for construction has been reduced to 45 mph.
The on and off ramps at the exits are not being moved, but they will be temporarily changed as work on the road moves from one area to another, Cairns said. They also are being rebuilt.
Much of the work is being done during the nighttime, so restrictions on traffic are being enforced from 9 p.m. to 5 a.m., according to Cairns. During June, the late night hours were used to set the structural steel on the bridge over Brown Street.
During 2002, several months of work was done under these restrictions, Cairns said, but that schedule was much more sporadic this year. Several light towers were brought in to provide light during that time.
For daytime work, rolling roadblocks operated by state police helped control the traffic and let construction vehicles access the median. That way, construction workers could more easily blast away the rock ledges in the median. The roadblocks stop traffic for no more than 10 to 15 minutes at a time.
While attention has been recently refocused on the westbound lanes and its bridges, work on the two eastbound bridges is primarily finished.
Approximately six different subcontractors are working on this project. E.D. Swett, of Concord, NH, is in charge of rebuilding the steel girder bridges, while Continental Paving of Londonderry is doing the paving.
Cairns said that a number of Caterpillars are being used for the excavations, such as a Cat 345, M318 and a 14G motorgrader. The bridge demolition, including the excavation of the bridge footings, is being handled, in part, by a Komatsu PL 350.
Not much earth is being moved during the project, only about 75,000 cu. yds. (57,000 cu m), Cairns said. A small amount of rock — approximately 2,000 cu. yds. (1,520 cu m) — also was removed to create a safety clearance for the new lanes.
I-293 is a spur of interstate I-93, which travels along the western and southern edges of Manchester, providing an alternate route to that part of the city. Together the highways create a loop around the city, with I-93 circling around eastern and northern sections.
Work on the highway started in June 2003 and is expected to be finished in September 2004. The job carries a $13 million price tag.
Another project designed to add the extra lane farther to the east on I-293 is planned, but that will come under a separate contract in the future. The bidding process, on that portion of the job, has not yet started, according to Paul Nadeau of the Construction Bureau of the New Hampshire Department of Transportation.