projects

I-93 Widening
Exit 1 Reconstructin Contracts C & D

Salem, New Hampshire

Client: New Hampshire Department of Transportation

Services

  • Drainage Design & Pollutant Treatment
  • Highway Interchange Design
  • Multi-Discipline Design Coordination
  • Project Sequencing Breakouts
  • Soundwall and Retaining Wall Design
  • Traffic Control/Management/Staging

Project Summary

As part of the I-93 corridor reconstruction program Hoyle, Tanner was responsible for redesign of the Exit 1 three-legged interchange to support replacement of seven existing “Red-Listed” bridges along new alignment and grade. Innovative stormwater management with pollutant treatment was integral to highway design in order to achieve required levels of pollutants removal. Improvements were proposed to be constructed under two separate construction contracts in order to expedite early bridge replacements and then stage remaining ramp redesigns with overall corridor widening efforts.

In more detail the Exit 1 Interchange Improvements design involved:

  • Realignment of highway ramps from new mainline layout onto Rockingham Boulevard;
  • Coordinated construction sequencing to facilitate the replacement of seven of the existing “Red List” bridges with five new or rehabilitated structures;
  • Final design of a sound abatement barrier adjacent to existing residences;
  • Delivered unique culvert solutions for maintaining stream flow through the interchange via jacking and sleeves utilizing numerous pipe types;
  • Designed stormwater treatment infiltration, pretreatment, detention, retention facilities;
  • Accommodated the requirement to maintain both the mainline and ramp traffic operations while proposing a highly aggressive two-year construction duration;
  • At the request of the client, accommodated the need to phase the interchange improvements into two separate construction contracts advertised three years apart from each other.

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