Milwaukee goes deep. To reline brick sewer

The 60-inch diameter brick combined sewer line on Milwaukee's (WI) North Side had faithfully done its job for over 100 years. But the line, which was buried 75 feet underground in the 1880s, demonstrated that the passage of time had taken its toll. Calcium and other mineral deposits were beginning to show up on the two-foot thick walls. Although there are many miles of brick sewer lines still in operation in Milwaukee, it was clear that it was just a matter of time before the 60-inch line running under Humboldt Avenue would require major repairs. Considering the depth, repairing the collapsed sewer on an emergency basis could cost $1.5-2 million to repair. In late 2002, the city resolved the situation by installing a 42-mil thick National Liner cured-in-place liner through 758 feet of the old brick sewer. Prior to proceeding with the $659,000 project, the contractor, Visu-Sewer Clean & Seal Inc., a National Liner installer, did a thorough analysis. For the Pewaukee, WI, firm, this included walking the line and carrying out comprehensive videotaping. The crew focused particularly on areas where calcium deposits had accumulated and bricks had fallen away from the wall. These findings were used in certifying that the sewer was ready to be lined. Samir Amin, construction supervisor in charge of inspectors for the city of Milwaukee, said the main advantage of using cured-in-place lining is the cost. 'It is much cheaper than tunneling. At a depth of 70 feet and with a sewer of this diameter, tunneling would have doubled or tripled the cost,' he said.