As part of the I-80 reconstruction project, Geneva Rock Products Inc. was responsible for repairing and upgrading other elements of the infrastructure. The contractor made new cast-in-place concrete median barriers and Gerber Construction, a subcontractor based in Lehi, Utah, demolished and replaced a 328-foot bridge on the westbound side of the interstate.

“The bridge deck was being reconstructed along with the roadway, and we decided to replace the entire bridge to give it a full 75-year life.” says Matt Zundel, Utah DOT (UDOT) resident engineer.

Storm drains on both sides of the highway were also due for an upgrade. An effective drainage system was critical to controlling erosion and protecting drivers, and the new pavement, from standing water. Geneva Rock performed a video inspection of the existing pipes to determine the extent of repair or replacement required.

On the eastbound side, about 20 reinforced concrete pipes drained water down a steep, 100-foot slope to Silver Creek.

“Most of the concrete pipes were in excellent condition. We only had to replace one,” says Joe Serre, Geneva Rock project manager.

It was a different story on the westbound side, where corrugated metal pipes had been installed on an even longer slope. Almost all were significantly deteriorated.

The pipes were buried 5- to 30-feet-deep into the canyon’s side. The contractor would have to excavate to the required depths, stabilize the trenches, install new pipe, and backfill — a time-consuming process that could compromise the ground under the road.

“This turned out to be the perfect application for sliplining,” says Serre.

Subcontractor Val Kotter and Sons, from Brigham City, Utah, cleaned the pipes and installed about 2,000 feet of PVC pipe liner inside the 24- and 36-inch corrugated metal pipes.

UDOT engineers wanted to take a different approach for the 60-inch pipes. Although the agency had used liners for larger pipes, they found the larger rolls of liner material harder to handle and more expensive to transport. They wanted to try centrifugally cast concrete pipe repair instead, as an experimental feature.

Guaranteed Waterproofing and Construction repaired about 400 feet of pipe using the CentriPipe system, which involves pumping in self-consolidating mortar to fill damaged areas, then spraying a layer of concrete inside the pipe with a spinning, retractable applicator. The applicator is run back and forth through the pipe, adding layers of concrete until the new lining reaches a desired thickness. Although the process costs more than slipforming, the subcontractor performed the work at a reduced price that kept the project within budget.