Diaz Corporation of Maine was awarded a job from the Maine Department of Transportation in the Fall of 2002 to replace a failing corrugated metal culvert. When a 144" diameter metal tunnel started to collapse in Lewiston, Maine, an innovative installation method was developed. In order to avoid excavating the existing pipe, the contractor had the chioce of either pulling or pushing the replacement concrete pipe into place within the metal pipe.
Choosing to push the pipe in, Diaz fabricated a special cart to be driven into the metal culvert. Jacks were then used to lift the pipe off the ground while it is pushed down the culvert with a Bobcat. Once in the correct location, the jacks were lowered and the pieces of pipe were pulled together with two 6-ton come-alongs. The cart was then pulled out and the process was repeated for the 1,048 feet of culvert.
With no digging involved, the project was started during the winter months, which is unusual for this type of work, but great for the schedule. At forty-five to fifty-five feet underground in spots, the tunnel runs under the Maine Turnpike and would have caused major disruptions if excavation had been required. This job was just one of the many ways to be creative and work with owners to find viable solutions and alternatives to conventional methods.