Located about 1500 ft. downstream of the Hooover Dam, the nearly complete Colorado River Bridge will connect the Nevada and Arizona sides of the new highway that will bypass the dam, and offer a magnificent view of the Dam and Lake Mead.
In 2005 the World of Concrete made Las Vegas its permanent home at least for another five years making it possible to offer an exclusive behind-the-scenes tour of the massive Hoover Dam Bypass project, which had just begun. Now, five years later, the project is nearing completion. Attendees of the annual tour no longer need to visualize what the pubic works landmark will look like it looms above them as they head toward the Hoover Dam Visitor Center.
Tour attendee Frank Kosliski, materials engineering consultant, remembers the inaugural Editorial Tour. "It consisted of parking near the trailers and climbing up rocks to the construction site," he says. "We were given the original drawings of the bridge plans." His copy is framed in his office.On Sunday, tour participants met Jeff St. John, deputy project manager with contractor Obayashi/PSM JV, for a comprehensive project update before touring the dam. According to St. John, both sides of the bridge deck are 100% complete, as well as the twin hollow cast-in-place arches that span 1060 feet across the river and 900 feet above the water.
"This is the hardest concrete we've ever placed in our lives," says St. John of the arch foundations. He wasn't referring to psi (4000). Instead, he discussed working conditions that included digging 300 feet down into the soil and pouring stiff, low-slump concrete in temperatures that soared well above 100° F. The concrete was placed at night, to avoid daytime temperatures and traffic. (The area's ambient temperature range between 90º F to 100° F at 9 p.m. in August .)
The $114 million bridge is expected to be completed by September. So when World of Concrete 2011 rolls around, tour attendees should find more than an engineering and construction tour; those daring can stroll along the pedestrian walkway planned for the bridge.
"You can't get this tour by just going to the dam," says Rick Yelton, editor in chief of MASONRY CONSTRUCTION and THE CONCRETE PRODUCER magazines.
Hoover Dam Bypass
Cost: $234 million ($114 million for the bridge)
Contractor: Obayashi / PSM JV, a joint venture of Obayashi Corp. and JSM Construction USA Inc.
Description: Construction of the 1900-foot span began in early 2005. At 1060-foot spans, the twin arches are the longest cast-in-place arches in North America and the fourth-largest in the world. The new road will be 900 feet above the Colorado River.
The arches of the Colorado River Bridge will include approx.:
- 8199 cubic yards of 10,000-psi concrete
- 8364 cubic yards of 600-psi concrete in the pier columns and caps
- 600 to 700 pounds of rebar per cubic yard
- 800 pounds of cement per cubic yard
- 200 pounds of fly ash per cubic yard.