Travelers in the “Granite State” will ride in style when they drive over the Saco River and the New Hampshire Railroad bridges when a $12.8 million project to replace the spans and upgrade the roadway is completed.
The bridge replacement project is under way in Bartlett, N.H. and includes the replacement of the bridge that carries U.S. Route 302 over the Conway Scenic Rail Road and the bridge over the Saco River; reconstruction on Route 302 on an improved alignment — including 5,000 linear ft. (1,524 m) of new water main with services for the Lower Bartlett Water Precinct; rehabilitation of 1 mi. (1.6 km) of the existing roadway; and, reconstruction of approximately 1,500 ft. (457 m) of West Side Road.
L. Robert Landry Jr., is a project manager of the New Hampshire Department of Transportation’s (NHDOT) Bureau of Highway Design in Concord, N.H. NHDOT is the project’s owner, designer and contract administrator. The project located on Route 302 begins approximately 1,400 ft. (427 m) southwest of the West Side Road intersection, and then continues northeast for 1 mi. (1.6 km).
To maintain vehicle traffic, work between the bridges will be done with alternating one-way traffic during daytime hours, Landry said.
According to John Bousquet, vice president of R.M. Piper Inc., the project’s Plymouth, N.H.-based general contractor, both bridges were built in the 1930s. The existing 224-ft. (68 m) long, two-span concrete and steel bridge over the Saco River will be replaced with a similar bridge. The 90-ft. (27 m) long, concrete and steel bridge over the Conway Scenic Rail Road, he said, will be replaced with a 170-ft. (51 m) long, 36-ft. (11 m) wide, skewed precast concrete arch structure.
Landry said that one of the project’s most difficult challenges was where to locate both bridge replacements. He said three options were considered and after meeting with town officials, the decision was made to locate the bridge replacements offline to the east and west while maintaining traffic on the existing bridges.
Bousquet noted that 3,500 ft. (1,067 m) of Route 302 will be excavated 2 ft. (.6 m) deep and replaced with new gravel and asphalt. Along the road, 5,000 linear ft. (1,524 m) of ductile iron water main will be laid.
Budget issues with the Lower Bartlett Water Precinct, Bousquet said, resulted in his firm value-engineering this part of the project. The value-engineering consisted of using a different water pipe material than originally planned.
“We recommended a pressure Class 350 ductile iron pipe instead of the originally specified Class 52 ductile iron pipe. We also recommended eliminating some of the steel sleeved encasements at all road crossings and replacing them with restrained joint ductile iron pipe,” Bousquet explained, adding that both recommendations were accepted and resulted in a savings of approximately $120,000.
Heavy-construction equipment used for the project, Bousquet said, includes the following company-owned machinery: a Link-Belt 138 Hylab-5 80-ton crane; four Caterpillar 335 excavators, two Caterpillar 938 loaders, one Komatsu D-65 bulldozer, and one Volvo 290 excavator.
Construction is scheduled to be completed on Oct. 17, 2008, said Landry. CEG