I-580 project a beehive of activity
After more than 20 years of planning and often contentious debate, construction of the new freeway from the Mount Rose Junction to Washoe Valley is under way.
Nearly 200 employees of Fisher Engineering and it subcontractors as well as Nevada Department of Transportation engineers and inspectors are working on the entire length of the project simultaneously. That includes nine bridges in just eight-and-a-half miles, more than 18 miles of concrete drainage culverts and eight or nine walls to support the roadway as it winds along the hillside.
Add in a route that goes straight through one of western Nevada’s most active geothermal fields and the $393 million project is arguably the most complex engineering challenge in the transportation department’s history.
When completed, those bridges will be connected by a six-lane freeway that will carry an estimated 30,000 vehicles a day when it opens in 2011.
NDOT Spokesman Scott Magruder said the freeway should divert some 70 percent of the traffic that now must go through Pleasant Valley each day, effectively turning that piece of Highway 395 into “a country road.”
Residents there have long supported construction of a new freeway, saying the undivided four-lane route that passes by their homes is the scene of too many fatal accidents. Magruder said an accident in that area also completely halts traffic between Reno and Carson City because it’s the one place in that trip where there’s no alternative route.
The new divided highway will not only eliminate that problem but greatly increase capacity because of the additional lanes. And, he said, it avoids the stoplight at Mount Rose junction and will allow a 65 mph speed limit instead of the current 50 mph on Highway 395.
“This will cut at least five minutes off the trip,” he said.
Despite the work all along the route, nearly all of the activity is invisible to those driving on the existing roadway through Pleasant Valley.
The most visible part of the project is the collection of concrete pilings that will hold up the Galena Creek bridge. Dubbed “Stonehenge” by the project’s detractors, those pilings will eventually support a 1,700-foot cathedral arch bridge that, at its center, will soar 300 feet above the tiny creek.
Even with the bridge, one of the biggest technical challenges is that geothermal field just south of the Mount Rose Highway. NDOT resident engineer Brad Durski said the Galena Forest Bridge over that section is 900 feet long and 100 feet high. It is being built on footings rather than having pilings set into the ground because of the geothermal field.
“Engineers believe the caustic nature of the gases and moisture coming through that soil would erode conventional pilings in a few years,” he said. “There are a lot of measures being taken to ensure this holds up.”
Durski said it took seven different tries for NDOT and CC Myers, the subcontractor building all the bridges, to find a suitable way to build those pads. The pads consist of a limestone footing to counteract those caustic chemicals coming out of the ground and a special coating on all the columns to prevent any moisture from getting into the concrete.
During a recent tour of what will become I-580, construction was proceeding on every bridge and grade separation along the route. Huge trucks were hauling dirt and rock as high spots on the route are blasted away and used to fill the low spots.
“They had to do a lot of blasting in here because the basalt was so hard you couldn’t rip it with dozers,” Durski said.
But, he said, it’s the perfect aggregate to make strong concrete. He said so much concrete is needed for the project that Fisher Engineering brought in a rock crusher to make their own aggregate and installed a $2 million concrete plant to make their own concrete on site.
A 700-foot-long bridge is under construction at Steamboat Hills south of the geothermal field. There, the concrete pilings were complete and a tinkertoy-like structure of steel tubing and girders – what engineers call falsework – is being installed in between to support the concrete roadbed. The falsework is removed after the concrete has cured 21 days and thick steel cables running through the bridge are tensioned to set the road at the right level.
As huge cranes lifted the steel sections, a single workman standing on a girder 100 feet above ground guided them smoothly into place.
“The only thing that stops them is wind,” Durski said.
That bridge is followed by the smaller Pleasant Valley bridge, then Galena Creek. Structures at St. James Parkway, Brown’s Creek and Parker Ranch Road were completed by the original bridge contractor, Kraemer and Sons, before they opted out because of concerns erecting the Galena Creek Bridge would be unsafe due to wind.
The remaining two structures that will be built are the overpass at the Bowers Mansion interchange and the second half of the Mount Rose interchange.
Durski said that with more than 140 workers on the project, Fisher and the subcontractors are well on track to finish in 2011 as required. To help them do it, he said, NDOT has some 50 engineers and inspectors on site helping resolve problems, reduce errors and move the project along.
“The more we work together, the faster the job goes and the less we have mistakes,” he said. “This is the epitome of a partnering job.”
• Contact reporter Geoff Dornan at email@example.com or 687-8750.