RAW WATER MAIN EVALUATION AND REPAIR

Winston-Salem, North Carolina - Winston-Salem/Forsyth County Utilities Commission

SERVICES: Location of Appurtences • Pipe Dewatering & Cleaning • CCTV Inspection • Design • Bid Coordination • Electromagnetic Inspection • Contract Administration • Construction Inspection

WORK PERFORMED: 2010 – February 2011

OWNER CONTACTS

Mr. Jack Fitzgerald

(p) 336.747.7309 • jackf@cityofws.org

Mr. Ron Hargrove, Utilities Director

(p)336.747.7312 • (f) 336.727.8432 • ronh@cityofws.org

Suite 357, City Hall, 101 North Main Street, Winston-Salem, NC 27101

COST: $750,000

SCOPE OF WORK

Hydrostructures was retained by the Winston-Salem/Forsyth County Utilities Commission to evaluate the condition of a key raw water main that provides water to the Neilson Water Treatment Plant and the Thomas Water Treatment Plant from both the Yadkin River and Salem Lake. The raw main, which was originally constructed in the late 1940’s, included approximately 54,500 linear feet of 36-inch diameter prestressed concrete cylinder pipe (PCCP) and 9,400 linear feet of 48-inch welded steel pipe. A significant portion the raw main was out of service while the Thomas Water Treatment Plant was being replaced and the Utility had a unique opportunity to inspect and evaluate the pipe and make any necessary repairs without having to take the line out of service. The evaluation portion of the project was completed in several phases. First, crews located and evaluated the condition of all key appurtenances such as access manholes, blow-off assemblies, air release valves, isolation valves, etc. At the same time, areas were identified that needed to be cleared to allow access to the main. The main was dewatered through the access manholes and blow-off assemblies. Next, the pipe was cleaned using a combination jetter/vacuum truck to remove any debris that had accumulated in the pipe. The evaluation included closed circuit television (CCTV) inspection using a robotic camera to identify any visible defects or debris within the pipe, and electromagnetic inspection to determine the location of any broken reinforcing wires within the pipe wall itself. A final report was prepared that identified nearly $900,000 in repairs to the main and appurtenances. Subsequently, Hydrostructures, P.A. was retained to design the recommended repairs. The final project included replacement of approximately 2,600 linear feet of 36-inch PCCP pipe with ductile iron pipe, replacement or repair of 35 air release valve assemblies, installation of 2 new isolation valves, and other associated repairs. To expedite completion, two separate construction contracts were awarded and all needed pipe and materials were procured by the City in advance. The project was bid in the fall of 2010, and construction was completed in February of 2011. Minor challenges included coordinating access to the utility easement through private landowners and coordinating schedules with the construction of a new water treatment plant served by the main.

Browse our site today to learn more about us, our field services, our engineering and construction services, our GIS and utility mapping services, and to view photo galleries and descriptions of some of our projects. Call us today at (919) 542-5002 or contact us to learn more about how we can serve all of your water, wastewater, and stormwater needs.

Hydrostructures delivers comprehensive wastewater,  stormwater, and water system collection, conveyance, and management design and consulting services to clients throughout the Southeast and Mid-Atlantic, with offices in Pittsboro, North Carolina; Winston Salem, North Carolina; Cayce, South Carolina; and Virginia Beach, Virginia.

Top