- Company: Bradshaw Construction Corporation
- Industry: Water/Wastewater
- Location: Washington, District of Columbia
- Expected Completion Date: March 31, 2014
- Project Website
Bradshaw completed installation of 1,313 linear feet of 144 inch, and 1,014 liner feet of 72 inch rib and board tunnel for 110 inch and 48 inch fiberglass reinforced sewer. An Akkerman BS-120 digger shield and an Akkerman WM-60 TBM were used to excavate the tunnels. The work was in a busy urban area adjacent to the Anacostia River and a CSX Railroad. The tunnel was excavated through clay and fill with the presence of boulders. Additional challenges of the project included a launch shaft with a live sewer running through it, encountering an old, unidentified sewer, and soft, wet ground conditions prone to settlement and requiring ground modification.
What impact does this project have on America?
The sewer was installed by tunneling methods that minimized the impact on a densely populated area. The result of the sewer installation is the diversion of massive amounts of sanitary waste water to go to a treatment plant rather than the nearby Anacostia River.
What interesting obstacles or unusual circumstances did you overcome to complete the project?
There were many existing utilities that had to be avoided in the installation of the tunnel. Also, the ground conditions consisted of very soft running ground and nested boulders.
What dangers and risks did you encounter, and describe any extraordinary methods used to keep workers safe?
Our workers had to install the tunnel underneath an existing live sewer which was flumed and supported across the shaft.
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