I-15 CORE project concrete drainage pipes were installed under the freeway without shutting down traffic lanes.
Some of the ways UDOT keeps lanes open during construction are easy to see – for example lane shifts that allow work to occur safely next to traffic. And, UDOT is famous for moving already-built bridges into place. But some lane-saving construction takes place out of the public eye.
The I-15 CORE contractor, Provo River Constructors, used a method of installing drainage pipe that avoids open cuts that require lane closures. Called jacked pipe, the system uses augers or a tunnel boring machine with a cutting head to excavate under the freeway while simultaneously pushing pipe segments through to the other side. I-15 CORE recently won a Project Achievement Award from the Concrete Pipe Association for the jacked pipe installation.
Minger Construction of Chanhassen, Minnesota installed over two miles of pre-cast reinforced jacked pipe. The innovative construction methods used by the sub-contractor made for accurate and efficient installation.
Additionally, the project used long -rebar as reinforcement in small-gauge pipe, which is not common. “The rebar keeps the pipe straight,” according to Randy Whalen, Marketing Engineer of Oldcastle Precast, producer of the pipe. Keeping pipe “dimensionally accurate,” is more critical with smaller pipe since “pipe that is even one eight inch off can induce a curve.”
Given the maintenance of traffic constraints coupled with the aggressive schedule, the process of jacking pipe under the freeway was very important to the overall project. Provo River Constructors was required by UDOT to keep traffic lanes open during construction, explains Robert Stewart, I-15 CORE Deputy Project Director. “I don’t think you could have built this project without jacking and boring.”
For a more detailed description of jacked pipe construction methods, read an article posted by Concretepipe.org. Scroll down to the previous post to see a slide show of the work on the I-15 CORE project.