Maine Moves Ahead On CSO Projects

Lewiston's Most Difficult Job Faced Multiple Problems
January 2014, Vol. 69 No. 1

Big job, little room
"On Oak Street the buildings were right on the edge of the hole, but we only lost one front porch," he continued. "We were in a high-visibility, high-traffic area and had a dead-end street to contend with as well as dealing with gas mains, telephone lines and conduit, water mains and the 60-inch concrete sewer main that takes care of half the city. That is one of the main trunks for the city. If we broke that and it rained and we were at the wrong place at the wrong time, we would have gotten flooded. We really had to plan ahead and try to make it work, and if it didn't you had to hurry up and figure what you had to do. ADS helped us a lot with unique fittings and excellent service in terms of product availability and fabrication,” Gendron said.

"We had to buy a special excavator – a Volvo 305. There are only three in Maine with no counterweight on the back so we could get by the buildings. We dug down three feet in the street so we could sit down in the hole and reach everything. If we opened the roof on the excavator, we'd hit the overhead wires. Another obstacle we had to overcome was the rock ledge and also the diameter and the weight of the structures plus going under that 60-inch concrete sewer."

It took the Gendron six-member crew from April until November 2012 to install 800-feet of pipe. Typically, a 'normal' project of this size would take just a few days.

"The length of the pipe helped us a lot, however," explained Gendron. "We used different lengths of pipe, 13 and 20-feet and some others. The 13-foot pipe gave me the reach so I didn't have to have such a big excavator and we could use a 20-foot trench box instead of a 24-foot box. ADS also helped by making all the specialty fittings and the T-Bases. The job was originally designed for concrete pipe and structures but for all the things that had to be done, if we were trying to do it with concrete, there would be no way to complete the project.

"When we designed the T-bases, elbows were made specifically for the holes on the top and we just poured around them. It was much faster than it would have taken with concrete and actually I don't think it would have been possible to do the job. If you had to do those in concrete the weight would have been so much that you would have needed 100-ton cranes to set them, plus we didn't have the room. Ductile iron would have been too big and heavy.”