- ENGINEERING INFO
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When it came time to replace and upsize a failing 15” Techite water main on the Ft. Meade Army Base in Anne Arundel County, MD, PVC pipe was selected for the new line. The original design for the Mapes Road Water Main Replacement Project called for open-cut installation of 20” bell-and-spigot PVC pipe and horizontal directional drill (HDD) installation of 20” Fusible C-905® pipe to cross the Midway Branch Stream. PVC pipe was selected for its corrosion resistance, economic value, and consistency with Anne Arundel County standards. Fusible C-905® pipe was selected for the HDD crossing based on its material and dimensional continuity with bell-and-spigot PVC, compatibility with standard ductile iron fittings, and superior value to other thermoplastic pipe options.
Stella May Contracting, Inc. of Edgewood, MD was selected to construct the new waterline. In January 2010, Underground Solutions, Inc. (UGSI) contracted with Stella May to supply 680 LF of 20” DR21 Fusible C-905® pipe and fusion services for the HDD crossing. Sure Shot, Inc. of Centerville, MD was hired to perform the directional drilling.
During drilling operations “running sand” was encountered, making the bore extremely difficult to complete. Running sand, a soil condition in which loosely packed layers of sand become fluidized in the presence of liquids, makes it extremely difficult to maintain borehole stability. The crossing could not be completed via HDD without extraordinary measures and significant added cost. As a result, the HDD installation segment was switched to a combination of open-cut and jack-and-bore under the stream using an existing culvert. The change in installation method required the use of ductile iron elbows and sleeves to accommodate the horizontal and vertical deflections required to redirect the line and complete the jack-and-bore crossing.
The versatility of Fusible PVC® pipe allowed the installation to be completed without interruption when conditions dictated alternate installation plans. Compatibility with standard ductile iron fittings facilitated an easy switch. The project was completed in late spring of 2010.
|Pipeline Details and Project Summary|
|Owner:||American Water Military Division|
|Project:||Mapes Road Water Main Replacement|
|Location:||Fort Meade, MD (Anne Arundel County)|
|Pipe:||680 LF 20” DR21 Fusible C-905®|
|Contractor:||Stella May Contracting, Inc.|
|HDD:||Sure Shot, Inc.|
|Installation:||Open Cut, Jack & Bore|
|Contact:||Matt Boeh (412) 418-3201 firstname.lastname@example.org|