August 2016, Vol. 71 No. 8
Rehabilitation
Hobas Pipe Used To Rehabilitate Niagara Falls Sewer
In providing water and sewer services to 50,000 people through more than 16,000 residential, business and industrial accounts within Niagara Falls, NY, and adjoining areas, the Niagara Falls Water Board (NFWB) continually invests in infrastructure to maintain facilities while economically providing customer service. A prime example of this is the Iroquois Street Sewer
Lining project.
Originally built in 1917, the 54-inch diameter Iroquois Street Sewer is constructed of segmental block pipe. While past repairs on sewers and tunnels provided some good benefits, prominent infiltration – estimated at about 5 mgd – was discovered several years ago in a 2,220-foot length of the sewer. Upon further investigation, the problem “evolved into serious sewer structural and longevity concerns,” said John Goeddertz, Ph.D., senior project manager, AECOM.
“Due to the depth of the sewer, industrial nature of the surrounding land and presence of interfering utilities, a minimal amount of excavation was preferable,” added Goeddertz. “The specifications were written around sliplining the sewer and connecting tunnel with a small variety of acceptable liners.”
“The specifications were written around sliplining the sewer and connecting tunnel with a small variety of acceptable liners.”
AECOM also determined that a 36-inch, inside-diameter liner pipe was suitable for conveying the anticipated sewage flow, and use of only one push pit would minimize the potential for uncovering contaminated soils while excavating.
Yarussi Construction of Niagara Falls, NY, installation subcontractor on the project, selected the Hobas gasket-sealed, centrifugally cast fiberglass reinforced polymer mortar (CCFRPM) pipe over the other two, fusion-welded – acceptable materials.
As part of the sewer cleaning operation, intermediate manholes were excavated and a mandrel was pulled to verify proper clearance for liner insertion.
Once the host pipe was prepared, Yarussi inserted liner pipe southward and northward from a single push pit. In all, 1,175 feet of the segmented block sewer were cleaned and lined. The stretch was completed by open cut methods into the rock tunnel section, again using Hobas pipe.
Recorded loads reached maximums of approximately 10,000 pounds on the northward run, and 21,000 pounds southward, with a calculated friction factor of 0.21 and 0.45, respectively – “very typical in our sliplining installations,” said Rene Garcia, Hobas engineering supervisor.
“The principal goal of the project was to reduce inflow and infiltration, and the results have been promising, reducing chemical usage and pumping costs at the treatment plant, while also reducing wet-weather combined sewer overflow,” said Richard Roll, NFWB technical services director. “In addition, an old sewer in the process of failing has been replaced with one expected to provide many decades of reliable service.”
For more information:
Hobas Pipe USA
Comments