Florence Street over Shields Brook

Derry, New Hampshire

Client: Town of Derry, New Hampshire


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

Project Summary

The Florence Street bridge was a jack arch bridge with inadequate hydraulic capacity.  Due to the poor hydraulic capacity in an urban setting, heavy rain events would back up the Brook and damage adjacent homes.  Hoyle, Tanner completed an Engineering Study which included a recommendation to replace the bridge with a larger structure.  The replacement project was funded through the NHDOT Municipal Bridge Aid Program.

Hoyle, Tanner designed a 20′ span precast concrete box culvert on a 40 degree skew replacement structure.  The box culvert was selected due to the poor subsurface conditions at the site and increased the hydraulic capacity by 180%.  The box culvert was designed with baffles in each section to provide a natural gravel bottom throughout the bridge crossing.  The project included nearly 500′ of roadway and drainage improvements including a 2′ raise in grade at the bridge which accommodated the larger structure opening.

We provided bid phase administration and part-time construction observation and administration for the Town of Derry.  Due to the densely developed location of the bridge, coordination with the abutters to the project was critical to its success.

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