Fordway Road over Beaver Brook

Derry, New Hampshire

Client: Town of Derry, New Hampshire


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

Project Summary

The Town of Derry sought to replace the previous corrugated metal plate arches due to their poor condition and hydraulic inadequacy which resulted in upstream flooding. The Town also set a project goal of improvements to two nearby intersections; one of which was the sole access to the Town Transfer Station and Wastewater Treatment Plant.  The location of the treatment plant presented unique site constraints as the main supply line to the plant was located within 10 feet of the proposed bridge.

Hoyle, Tanner personnel designed 500 feet of roadway improvements, realignment of two intersections and drainage upgrades. Due to the inclusion of Federal funding, a full NEPA review process was required including preparation of a Categorical Exclusion document and coordination with state and federal resource agencies. We evaluated several bridge replacement options and selected a twin cell box culvert as the preferred alternative. With poor subsurface conditions, the twin cell box culvert did not require a costly deep foundation system. It also had the advantage of a shorter construction duration and smaller footprint which avoided impacts to the treatment plant supply line. Hoyle, Tanner personnel provided bid and construction phase services including near full-time observation.

The project was completed through the NHDOT Municipal Bridge Aid program with construction phase funding through the American Recovery and Reinvestment Act of 2009.

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