Record-breaking Bridge Stars In Rugged Nevada Route
The critics have called it "the bridge to nowhere." It has gone through over a decade of delays and setbacks. But the 1,722-ft-long, 295-ft-tall Galena Creek Bridge, one of the costliest, most controversial projects in Nevada's history, is finally nearing completion.
Crossing a small creek in a rocky, rural patch of northern Nevada about 20 miles southwest of Reno, it will be both the country's longest cathedral-arch bridge and the linchpin of a $600-million Interstate 580 extension between Reno and Carson City.
The 8.5-mile-long, six-lane freeway bypasses a busy, accident-prone stretch of U.S. Highway 395—which runs through Pleasant Valley, a small, unincorporated community in Washoe County—that handles 40,000 vehicles daily. Northern Nevada's most congested rural roadway, the two-lane undivided highway is susceptible to high winds and head-on collisions.
Nevada Dept. of Transportation (NDOT) officials hope the extension will divert up to 70% of the traffic away from Pleasant Valley while improving safety, reducing travel time and bolstering NDOT's reputation.
"This is a signature project, a showcase of our abilities, and proof that we can handle a job of this size and complexity," says NDOT district engineer Thor A. Dyson. "Completion of this project is important for the department's psyche."
Locals, however, are sensitive about the freeway's alignment and look. The project received vociferous feedback from residents and businesses who were determined to maintain the area's scenic beauty. The freeway, as a result, hugs the 5,000-ft-tall southern mountain range. The project includes $10 million for environmentally friendly landscaping and replanting.
"We listened to the community, and they wanted to minimize [the bridge's] appearance," says Dyson. The unobtrusive appearance, however, entails heavy engineering that includes nine bridges and 5 million cu yd of tricky excavation.
The high elevation also prompted NDOT to add a $2-million Boschung deicing system with sensors and deck-embedded nozzles that spray potassium acetate in four second intervals when the temperature falls below freezing (ENR 1/15/07 p. 24). The system—a first for the state—is being installed on four bridges.
Designed by CH2M Hill Inc., Englewood, Colo., with NDOT, the project includes three miles of asphalt frontage roads, 26,246 linear ft of mechanically stabilized earth walls, 14 miles of drainage pipe and 25 miles of concrete barrier rail. It travels through rugged terrain that required 18 months of continuous drill-and-shoot blasting. Large dozers, articulating trucks and backhoes with hammer attachments broke up rock, most of which was re-used. There were 40 pieces of earthmoving machinery at work at any one time. The biggest roadway cut, nicknamed "the Matterhorn," required the removal of one million cu yd of material.
"[The cut] is located in the middle of the freeway alignment, which made hauling tough," says NDOT resident engineer Brad F. Durski. Fill removal took the equivalent of 100,000 truckloads, he says.
The Galena Creek Bridge crosses a wildlife-rich creek and a former Galena mine. (Galena is a natural mineral form of lead sulfide used in batteries). The area is so rural that the job includes 20 miles of 8-ft-tall deer fencing, and crews have reported seeing black bears and mountain lions. Context-sensitive, the bridge has a 689-ft-long center-span arch that visually complements the curves of the neighboring hillsides.
"You want people to notice the bridge as little as possible," says NDOT bridge design engineer Troy Martin. "But when you do notice it, it should be pleasing to look at. It's a balance."
Trouble Brewing
The project went off-balance in 2006 when contractor Edward Kraemer & Sons Inc., Plain, Wis., and NDOT hit an impasse over the Galena Creek Bridge's erection method. The design called for a cast-in-place pilot truss erection method in which 18 steel segments are bolted and welded together, forming a structural framework. The contractor then adds rebar and concrete around the trusses to create the arch. But Kraemer feared the erection of the main span would be unsafe given the area's 80-mph winds. On May 18, 2006, NDOT terminated its $79.5-million contract with Kraemer and both parties walked away, dropping their competing claims.
The project, which had started in December 2003, now was stalled. Kraemer received $50.2 million for work completed, or 63% of its contract, leaving the overall project about 60% complete. While the extension had been scheduled to finish in early 2008, NDOT now needed to find a new contractor. "Our credibility was at stake," Dyson says. "It was imperative that we rise to the challenge."
On Nov. 6, 2006, NDOT awarded Fisher Sand & Gravel Co., Dickinson, N.D., a $393.3-million contract—the single largest contract in the agency's history—to finish the job, although the bid was 19.1% higher than the engineer's estimate. Kiewit Western Co., Concord, Calif., was the runner-up with a $415-million bid. The project drew only two bids due to bonding firms' skittishness over the escalating price tag, officials say. Total freeway costs had grown by $113 million, including Kraemer's payment, from the original estimate. NDOT cut its $130-million annual pavement repair and maintenance program by 50% to pay for the additional expense.
Fearing steep construction inflation, the agency felt pressure to award the project, said NDOT Director Jeffrey Fontaine, who left for another job shortly thereafter. "It would have likely ended up in litigation, and the project was already two years behind schedule. So we decided to make a clean break," he says.
Turning the Page
Fisher and bridge subcontractor C.C. Myers Inc., Rancho Cordova, Calif., also rejected the pilot truss erection method. Instead, they temporarily raised the creek floor elevation by 140 ft using 450,000 cu yd of compacted soil, with a 40-ft-wide, 400-ft-long diversion tunnel to maintain stream flow. Next, they created a 44-ft-dia, 22-ft-tall, 3-ft-thick shotcrete-reinforced temporary bridge arch and custom-fabricated an interior slipform for 40-ft sectional pours. "When you get up that high, there is no other way to do it," Fisher's Nevada manager, Joseph Miller, explains. A $2-million batch plant, using local basalt, was set up on-site. Thirty mixer trucks and a pair of 200-ft-tall pump trucks were used to place concrete.
The most crucial pieces of machinery were computer-controlled strand jacks from Enerpac Integrated Solutions, Butler, Wis. A dozen traveling 85-ton jacks lowered falsework for the pair of 62-ft-wide, three-lane parallel bridge structures. Conventional concrete falsework was too heavy for traditional cables and winches. In contrast, strand jacks uniformly grab, lift and lower cables through hollow centers at a dozen points. Suspended loads averaged 110,000 lb per jack, with lowering speeds of up to 60 ft per hour.
The falsework was assembled on the ground and lifted by crawler cranes positioned 30 ft away from the creek because of environmental concerns. The strand jacks, sitting on I-beams atop the deck, disassembled the falsework. No drilled holes were allowed in the deck, whereas most projects have smaller bridge widths and permit holes in the median and overhangs, says C.C. Myers' engineering manager, Bill Kidwell. "It would have been challenging to do this project without this jacking system," says Kidwell.
The project has had plenty of challenges. Early last year, for example, former C.C. Myers employee David Lee made a whistle-blower complaint that he had been ordered to use substandard concrete as a money-saving measure, triggering a federal DOT inspection.
"David Lee never worked on the Galena Creek Bridge," says NDOT spokesman Scott Magruder, who notes there have been up to 55 quality-control inspectors on-site. "He performed patching work on an approach bridge that, in his mind, was substandard. His accusations are without merit."
Discovered on the exterior southbound span during a March 2010 test by NDOT, a 30-ft-long, 1/16-in.-wide crack was caused by high-pressure air that had been pumped through a duct embedded into the concrete for cable tension. C.C. Myers performed a $900,000 NDOT-designed repair as a change order, with bolted steel plates and epoxy patches with concrete overlay.
Home Stretch
The project has since found its footings under Fisher. Contractor and owner now share the same office. "It's not often you get to work with a contractor for five years," Durski says. "This is the epitome of a partnering job." Fisher is currently on track to complete the job in mid-2012. The contract carries $12,700 per day in potential liquidated damages.
Galena Creek Bridge now stands in its final form. The 220-ft-wide mound of earth has been nearly removed from underneath the bridge, which is composed of a hollow arch and hollow columns to reduce its weight and materials. The seven-span structure features 340 miles of reinforcing steel rebar as well as four hinges made up of a dozen 3-ft-sq bearing pads for temperature deflection and seismic activity.
The bridge is supported by six concrete box-girder columns that measure 20 ft wide by 10 ft thick, with a dozen 4-in.-dia drilled shafts up to 60 ft deep at each pile cap. The arch is anchored by two pairs of thrust blocks, the largest being 40 ft wide and 50 ft tall. The thrust blocks, which work like spread footings, are tied together with link beams. As a result, the center arch has no columns.
Martin adds, "This was an aesthetic choice that the team concluded would make the space under the bridge more open and less obtrusive into the natural landscape."
