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Maine Moves Ahead On CSO Projects
Lewiston's Most Difficult Job Faced Multiple Problems
"This particular Lewiston job had some deep, deep cuts. They were down 25 to 30 feet in certain areas." Pelletier continued. "It was very challenging, especially for the maneuvering of the pipe because they were down so deep and one city block was only 40 to 50 feet across. You also have to haul off a lot of materials as in a city you don't have a location to store it. Line up the dump trucks, load the material and send it off. Once they had the installation completed and compacted, they were able to haul all the material back in to reconstruct the roadway."
For the overall project, the city contracted with Gendron & Gendron of Lewiston, a local construction company with a 42-year history in working with the city. "They usually save the 'best' for us," said Todd Gendron with a smile. “The Oak Street job was the middle part of the city’s separation initiative and we had to match up with the elevation with what had been done a few years before. They stopped when they hit the rock ledge.
“That's where we started – in the ledge. We couldn't blast. There was a 60-inch concrete sewer two-foot away from where we had to put in this 42-inch and 48-inch SaniTite pipe and it was three-feet deeper than the bottom of the concrete sewer. We also had other utility lines. We brought in a drilling company to drill holes eight inches on center in an area 20-feet wide by 300-feet long and then we hammered out rock with a hydraulic hammer. When we first started it was just to put in 200-feet of pipe, and we hit solid rock which was nine-feet higher than the invert of the pipe, so we had to hammer out nine-feet deep and 55-inches wide."
The ground conditions in Maine can vary literally from block to block. "About three years ago we did a storm water job about 18-feet deep but it was in clay on College Street – one street up from Oak," stated Gendron.