Crews will soon begin pouring the first of two huge concrete arches which will support the Galena Creek Bridge in Pleasant Valley.
The bridge - actually two parallel bridges - will be the most prominent feature of the I-580 project which will complete the freeway between Reno and Carson City.
It will be 1,725 feet long and 300 feet above the creek at its center. Each of the bridges will carry three lanes of traffic at 65 mph, replacing two lanes in each direction which now wind through Pleasant Valley at just 50 mph.
Department of Transportation spokesman Scott Magruder said it should shave as much as five minutes off the trip. And, he said, it will help eliminate the head-on collisions which have caused numerous injuries and fatalities on the existing highway.
NDOT Assistant Director of Operations Rick Nelson said the bridge, one of nine in the 8.5 mile project, is the critical piece.
"In theory, when they finish these two bridges, the project will be done," he said.
It is also the most expensive piece at $95 million out of the roughly $450 million total cost of the project.
The original plan was to pour each arch in two pieces, then raise and connect them together at the peak. Concerns about the difficulty and safety of raising the huge arch pieces caused the original contractor to bail out.
The new bridge contractor, CC Myers, is taking a completely different approach. The company basically filled in the Galena Creek Valley with dirt up to the base of the arch supports - moving four million cubic yards of earth on a conveyor belt from the hills to the north. They crews built a steel support platform on top of the in the shape of the arch. Piece by piece, each of the two arches - one for each bridge - will be poured in forms on that "falsework" structure.
Finally, the roadbed will be constructed atop the arch.
After the southbound bridge is finished, the northbound arch and roadbed will be constructed in the same way.
Then the falsework and all the dirt below it will be removed, Nelson said, and the creek restored.
In the meantime, the creek continues to flow through a large concrete culvert at the base of the mound of dirt.
Nelson said the contractor's goal is to get the first arch finished before winter. He said they hope to begin pouring concrete in a week or two.
Even as crews work on the Galena bridges, the prime contractor Fisher Sand and Gravel of Phoenix is working on the other nine bridges and the rest of the freeway. He said everything is pretty much on schedule at this point and the entire project should be done in 2012.
Contact reporter Geoff Dornan at email@example.com or 687-8750.