City of Gloucester, MA Confronts the Perfect Storm of Utility Infrastructure Problems with Fusible C-905® Pipe

Bisecting the City of Gloucester, the Annisquam River effectively makes East Gloucester an island. For the last 100 years, water to this section of town was fed through dual cast iron mains located in the Blynman Canal utility tunnel. A break in either of the aging cast iron mains would have been catastrophic, potentially leaving half of the City without water. A new transmission line was required to secure the future of the City's water supply. To further complicate matters, a land- and marine-based exploration program revealed a complicated glacial stratigraphy overlying an erratic granite bedrock surface. As these types of geotechnical challenges had resulted in significant construction issues during past attempts to cross the canal, the City of Gloucester faced a significant design and construction challenge.

The City contracted with Fay, Spofford & Thorndike (FST) to manage the overall design of the project. In order to meet demand, it was determined that two 20-inch diameter pipes would be required. The most efficient and cost-effective route for the new water line would require crossing the canal using horizontal directional drilling (HDD). FST subcontracted the difficult HDD design to trenchless specialist, Brierley Associates. To accommodate the depth of burial, drill path geometry, and the anticipated pull forces, Fusible PVC® pipe was selected as the preferred pipe material for the HDD crossing. Due to easements and laydown restrictions, the final HDD profile required two 1,100 LF shots of 20-inch diameter Fusible C-905® pipe to be drilled with less than 25-feet of separation between them.

The low bidder, Aqua Line Utility Incorporated, enlisted the HDD services of Directional Technologies, Inc. to install both drill shots. Open-cut installation, final tie-ins, connections, and testing were completed by Aqua Line Utility. Underground Solutions, Inc. provided the 3,365 LF of 20-inch DR18 Fusible C-905® pipe and fusion services.

"Fusible PVC® pipe was the product of choice for the Annisquam River project because it allows for the use of standard ductile iron fittings, and most importantly, because it provided the required flow with the smallest diameter of pipe. This was a key benefit because we knew past attempts at crossing the canal with large diameter pipes encountered significant issues. Smaller was better." Justin Gould Fay, Spofford & Thorndike

Pipeline Details and Project Summary
Project: Annisquam River Crossing Water Main
Location: Gloucester, Massachusetts
Owner: City of Gloucester
Prime Engineer: Fay, Spofford & Thorndike
HDD Engineer: Brierley Associates
General Contractor: Aqua Line Utility Incorporated
HDD Contractor: Directional Technologies, Inc.
Pipe: 3,365 LF 20-inch DR18 Fusible C-905®
Installation: Horizontal Directional Drill & Direct Bury
UGSI Contact: Matt Boeh (412) 418-3201

Fusion Process

Multiple String Pipe Layout

Pipe String with Rock Reamer

Large Granite Boulder Removed from Borehole with Reaming Marks

Pipe Emerges from Borehole

Two HDD's Completed in Close Proximity