In Business Las Vegas, July 13th, 2007
While CityCenter's hotel towers rose out of the ground, the neighboring Cosmopolitan resort seemingly had just a fence surrounding a deep hole.
But what looked like a stalled project really was the beginning of a Strip rarity: A deep, subterranean parking garage.
After a massive excavation, the project 1 1/2 years later is finally peeking above ground level, with a design that's one of a kind in
Las Vegas
.
"They were going up with their buildings, and we were going down," said
Steve
DeWees, project executive
with Perini Building Co., general contractor for both Cosmopolitan and MGM Mirage's CityCenter.
Instead of a traditional "topping off" ceremony, in which crews celebrate putting in place the highest point, Cosmopolitan had a "bottoming out" party.
The five-story, underground parking garage drops 85 feet below ground.
Beneath that is an 8-foot-deep layer of concrete. And below that are 3,000 concrete-filled pipes that extend 100 feet further down.
An underground river runs through the earth just 20 feet below the Strip. Cosmopolitan builders had to divert the flow around the garage and build a pumping system for streams that resist the rerouting.
The garage will cost $50 million, as opposed to the $10 or $12 million that an above-ground parking structure would have run. But the Cosmopolitan owners, organized under the name 3700 Associates, had just 8.5 acres and a limit on how high they could go, based on airplane flight patterns.
"The reason it's happening is the value on the property above the Strip is so expensive,"
DeWees
said. "They're essentially creating real estate by going down."
The Palazzo has a deep, underground parking garage in the works. Other than that, other Strip properties have just minimal underground space.
Building a deep structure requires significant planning.
If things go wrong, the heavy resort (and the Cosmopolitan has two, 50-story towers) sinks into the ground. Mandalay Bay had that problem in the late '90s, and crews had to reinforce the structure after it had been already built.
Another risk involves the water table. If the Cosmopolitan pumped out enough of the river's water to lower the level at which the river runs underground, every property that sits on top of it would sink.
Already water seeps through the 30-inch-thick wall around the perimeter, known as the "slurry wall."
Slurry walls are uncommon in
Las Vegas
, not because of the harder-than-concrete ground material called caliche, but rather because underground garages have never before been in demand.
The technique, however, has been used in dams,
Boston
's Big Dig underground highway and
New York City
's former World Trade Center.
The Cosmopolitan slurry wall surrounds the perimeter of the underground garage. Named for the process by which dirt was excavated, the wall in place is made of 30 inches of concrete, supported by thousands of bunches of cable. The cables spike out 85 feet into the surrounding ground, angled slightly downward.
To place the support cables, known as "tie backs," Cosmopolitan builders had to get permission from neighboring properties.
Cosmopolitan's ground floors will almost abut the Jockey Club, the timeshare property that sits just a few feet away on the north side. Just south of the Cosmopolitan is CityCenter.
Construction started in October 2005, a year after the project was announced. The project is run by a partnership headed by well-known
developer
Ian Bruce
Eichner
.
Excavation on the Cosmopolitan started in January 2006 and ended in August of that year.
Cosmopolitan is one of six major resort projects now under construction on the Strip.
Las Vegas Sands Corp.'s Palazzo is scheduled to open by the end of the year, and Wynn Resorts' Encore is slated to open by the end of next year.
Eichner
's Cosmopolitan project will open during the single biggest quarter of resort openings, measured by number of hotel rooms or the cost of the projects, in
Las Vegas
history.
The Global Hyatt Corporation, an 80,000-square-foot casino, 265,000 square feet of retail and dining and an 80,000-square-foot spa. Two glass-covered towers are being constructed, along with a five-acre pool level below.$3 billion Cosmopolitan will have nearly 3,000 rooms, 150,000 square feet of meeting space managed by
Cosmopolitan is expected to open in December 2009, in the same quarter as CityCenter as well as Fontainebleau, at the north end of the Strip.
Boyd Gaming Corp.'s Echelon Las Vegas is scheduled to open in the third quarter of 2010.
