University of New Hampshire


Hoyle, Tanner & Associates, Inc.


Quad Way Steam Project


Utility Construction

  • Replaced approximately 140’ of (2) 12” HW, 3” HPS, 2” PCR, 2” DHWS, and 1.5” DHWR. This 140’ involved excavating approximately 10’ in depth and 15’ in width to access the tunnel. Tunnel panels were removed, cleaned, and piping and supports were removed. Approximately 200 ft. of concrete was repaired. New FRP supports and pipe slides/guides were installed. Tunnel panels were reinstalled and waterproofed. Trench was backfilled (approximately 600 yards of material), and restored with loam and hydroseed.
  • The depth and length of the trench proved to be challenging, requiring a significant amount of shoring. Also, existing site utilities crossed at various depths and locations throughout the length of the trench, requiring support and careful excavation. Given how certain utilities were installed, portions of the tunnel roof could not be removed for the demolition and re-installation of the supports and pipe. This required the crew to slide 60’ lengths of pipe underneath utilities, shoring, and tunnel panels with the aid of an excavator. The majority of the work was performed in confined space conditions—increasing the difficulty. Construction sequence was essential to the successful completion of the project within the given time frame – conditions forced R.H. White to make frequent adjustments to the plan. The location of the construction was in an area with heavy pedestrian traffic; site safety and proper housekeeping were essential to protecting the public.

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