Johnson and 11th Streets in La Crosse, Wis., were scheduled for replacement of their sidewalks, curbs, gutters and pavement, but first, a deeper problem needed to be addressed. “We had observed pavement and ground settlement in the street, curb, gutter and adjacent grass terrace area,” said Steve Asp, city assistant superintendent–sewer. “There is a lot of flow during rain events because several other large storm water pipes tie into the manholes on either side of the 72-in. pipe. We suspected soil migration through the joints of this storm line and tried patching them with mortar several years ago, but the issues of settling continued.”
The 72-in. pipe, dating back to 1950, still was in great condition with imperceptible deterioration. It was determined that the stress on the pipe joints resulted from the pipe’s 28-ft depth and the sheer volume of flow during rain events. Asp researched his options. Lining the pipe was cost-prohibitive due to the depth, and would require excavating pits on either side of the pipe section. Chemical grouting of the joints—a short-term solution, at best—also was rejected.
Finally, Asp discovered HydraTite Internal Pipe Joint Seal, distributed by Cretex Specialty Products. The seal requires no excavation or water removal from the pipe, and features limited surface preparation, quick installation and a 50-year design life. Ultimately, seven HydraTite seals were installed in only seven hours by a two-man crew in the pipe and one top man. Access was through a 78-in.-diameter block storm manhole with a 24-in. frame and chimney opening. The seal repaired any misalignment of the joints and formed an impenetrable barrier against further infiltration.
It has been rainy this year in southern Wisconsin, but, equipped with the new seal, La Crosse no longer has that “sinking feeling.”