Lyndeborough Road Bridge

New Boston, New Hampshire

Client: Town of New Boston, New Hampshire


  • Bidding Administration
  • Construction Administration
  • Construction Observation
  • Design
  • Engineering Study
  • Permitting

Project Summary

The existing bridge carrying Lyndeborough Road over the South Branch of the Piscataquog River was narrow with substandard roadway approaches. Due to the deteriorated condition of the deck, steel stringers, abutments, rail, and other characteristics, the bridge was also listed on the NHDOT Red List. Hoyle, Tanner studied bridge, roadway, and traffic control alternatives in order to construct a replacement of the bridge, roadway approach improvements, and improvement to the intersection of Lyndeborough Road and Misty Meadows Road.

The bridge was replaced with a 50-foot-long single span steel stringer structure on cast-in-place concrete abutments and wingwalls founded on ledge. The roadway approaches were improved to provide better sight distance, an improved horizontal alignment, proper roadway superelevation, and the creation of a “T” intersection with Misty Meadows Road. To maintain traffic during construction, a full traffic detour was implemented, which helped to accelerate the construction as well as keep costs down when compared to constructing the project in phases. Hoyle, Tanner, at the request of the Town, developed a timber guardrail and bridge rail system as opposed to a conventional galvanized steel guardrail system.

We provided all design, permitting, Right-of-Way coordination, utility relocation coordination, cultural resource coordination, and construction phase services for the project. The project was funded through the NHDOT State Aid Bridge Program.

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