2020 CANADIAN CONSULTING ENGINEERING AWARDS
WATER RESOURCES
AWARD OF EXCELLENCE
Northwest Arm Trunk Sewer Rehabilitation
Robinson Consultants
With CIPP, on-site fabrication and installation were feasible without disrupting the public’s use of the shoreline during construction.
“This challenging project, which broke several Canadian records, was completed on a very tight schedule, caused minimal disruption to the neighbourhood and saved considerable
Non-standard design CIPP design standards under ASTM F1216, Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the Inversion and Curing of a ResinImpregnated Tube, are based on circular
Northwest Arm Trunk Sewer Rehabilitation, Halifax
alternate methods.”
Owner: Halifax Water.
www.canadianconsultingengineer.com
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Constraints The Northwest Arm Trunk Sewer (NATS) was one of the most challenging cured-in-place pipe (CIPP) rehabilitation projects ever completed in North America. Several Canadian records were broken in the completion of this project, including the longest single continuous CIPP instal-
money compared to –Jury 46
Halifax Water required the renewal of an inaccessible, 100-year-old, largediameter, 4,000-m long trunk sewer that was exfiltrating into the Northwest Arm inlet, a major recreational and natural asset, during rain events. Robinson Consultants was tasked with restoring both the sewer’s structural integrity and its intended flow capacity, extending its service life up to 75 years, removing debris, creating a corrosion barrier and eliminating contamination of the coastline. The project was executed in a cost-effective manner while significantly reducing social and environmental impacts.
lation length at 682 m. The project's engineering scope included closed-circuit television (CCTV) inspection, condition assessment, feasibility study, constructability, detailed design, tendering, contract administration and site inspection for the rehabilitation of more than 4,000 m of combined trunk sewer, ranging from 1,200-mm diameter round pipe to 1,200 x 1,500-mm arch pipe, located in some of the most difficult-to-access residential terrain in Halifax. The NATS alignment meanders along the inlet’s shoreline anywhere from 0 to 10 m from the water’s edge and is landlocked by a Canadian National (CN) Railway track with bridge access only. In terms of access challenges, it is located mainly on built-up, multimillion-dollar historic residential waterfront properties, steep shoreline slopes, 100-yearold load-restricted CN bridges and a hydroelectric corridor. The project was financed by the Clean Water and Wastewater Fund (CWWF) with an ambitious timeline for completion. While a typical project of this size and magnitude would take more than 12 months of planning and engineering, the team was able to successfully complete all such requirements in seven months to meet the schedule.
Award-winning firm Robinson Consultants, Ancaster, Ont. (Kevin Bainbridge, A.Sc.T.; (prime consultant): Patrick Moskwa, P.Eng.; Ian Doherty, P.Eng.). Other key players: CBCL (hydraulic modelling and mechanical engineering).
October/November 2020
2020-10-05 9:16 AM
