Big sewer project's big pipe is parked in Brooklyn
In the northwest corner lot at the intersection of S.E. 17th Avenue and Holgate Boulevard – once used to stage TriMet MAX light rail construction materials, and before that a small shopping center – there is currently a large number of massive pipe segments.
BEE reader Steve Szigethy pointed them out, and said he suspected they might be part of a City of Portland infrastructure project.
He was right. The pipes – actually, they're fiberglass-reinforced pipe lining segments – are to be used in the Portland Bureau of Environmental Services (BES) "Taggart Outfall Repair Project", which is to take place just north, on S.E. Powell Boulevard.
The project finds BES repairing about 3,700 feet of the 114-year-old "Taggart Outfall" sewer tunnel, a large brick sewer tunnel measuring from 58 to 120 inches in diameter, and buried from 20 to 75 feet deep.
This is a challenging project – because the location is deep underground, and is close to TriMet MAX light rail tracks, the Union Pacific Railroad tracks, and Highway 26/Powell Boulevard. But, when it's complete, it will increase the sewer's resiliency to earthquake damage; extend its service life for another 100 years; and help prevent sewage releases into buildings and streets should a major earthquake occur.
We found it fascinating how they're "repairing" this sewer tunnel. Earlier this year, crews built a 15-foot-diameter, 35-feet deep sewer access shaft on private property on S.E 13th Place at Powell Boulevard, just east across the street from the Portland Fire & Rescue Logistics yard.
In May, workers laid 2,725 feet of steel railroad tracks inside the existing sewer tunnel, and then lowered a small-yet-mighty electric locomotive and a pipe lining cart into the sewer tunnel, and placed them onto the tracks.
By mid-July, crews had already begun installing the fiberglass-reinforced pipe – called a "slip lining" – inside the sewer tunnel. Using the electric remote-controlled locomotive, crews began pushing several of the 330 segments of 8-foot-long straight pipe, and 36 segments of joint pipe.
To accommodate the bends in the tunnel, workers also were assembling new "Tunnel Liner Plates" made of steel.
Then, every 100 feet, workers are pumping high-strength grout between the liners and plates and the aging brick walls of the tunnel.
"Putting in the slip lining is a tight fit, but this process is working very well," a worker at the site commented to us.
In the end, crews are essentially constructing a new sewer inside the old brick sewer. It's a needed infrastructure upgrade which, when it's completed in late September, most folks won't even know took place. Unless they read THE BEE!
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