KINGMAN - The completion of the support arch for the Hoover Dam Bypass Bridge is so close you can almost touch the other side. Approximately six feet of open air separate the Arizona side from the Nevada side of the arch, said David Zanetell, Federal Highway Administration project manager for the bypass.
That six-foot gap will close by the second or third week of August, when crews pour the final concrete section, he said. The 1,060-foot arch will be the longest concrete arch in America when it is finished.
However, drivers will have to wait another year before the rest of the bridge is finished, Zanetell said during a press conference Friday morning.
The concrete legs of the arch will have to be stabilized and the cables currently supporting the arch will have to be removed on the 1,900-foot long deck of the Mike O'Callaghan-Pat Tillman Memorial Bridge.
When it is finished, the bridge will stand 890 feet above the Colorado River, 1,700 feet downstream from the Hoover Dam, and will withstand sustained winds of over 100 mph, according to Zanetell.
The bridge is named after former Nevada Governor Mike O'Callaghan and Pat Tillman, an Arizona State University graduate and Arizona Cardinals football player who was killed while serving in Afghanistan in 2002. O'Callaghan died in 2004.
The bridge will link 2.2 miles of new highway approach on the Nevada side and 1.4 miles of new highway on the Arizona side of the dam to create a 3.6-mile bypass around Hoover Dam, Zanetell said. The entire project, including the four-lane highway approaches on either side, will cost $240 million, he said. Around $100 million is coming from the federal government and another $100 million is from bonds advanced from Arizona and Nevada. The remaining $40 million is coming from Nevada and Arizona, with each state contributing $20 million.
The project is a collaboration of the FHWA, Arizona and Nevada Departments of Transportation, U.S. Bureau of Reclamation, the National Park Service, the Lake Mead Recreation Area and Western Area Power Administration.
"This wouldn't have happened without all these agencies," Zanetell said.
The idea of a bypass to help with traffic congestion and accidents and improve security around the dam area has been talked about for more than 50 years, he said.
"The accident rate in the area being bypassed is three times the accident rate on U.S. Highway 93 on either end of the project," he said.
The bypass will minimize the potential of pedestrian vs. vehicle accidents on the dam, Zanetell said. It will also remove the traffic bottleneck at the dam caused by vehicles stopping for pedestrian traffic.
In 1999, almost 2 million people visited the dam, according to FHWA.
"It's neat," said David Eis, referring to the bridge. Eis was visiting Hoover Dam from Colorado.
"I understand it was necessary," said Helma Berkers, from the Netherlands.
"It's pretty amazing," said Dennis Stroer from the Dallas-Fort Worth area.
"I think it's brilliant," said Jo Clemes from Scotland.
According to FHWA, it should take a motorist 16.5 minutes to travel the existing 6.3 miles across the dam. Many times, accidents or congestion has resulted in traffic backups of more than 10 to 15 miles, with motorists waiting two to five hours to cross the dam.
According to FHWA, in 1993 5,500 vehicles crossed the dam per day and 18 to 20 percent of that traffic was commercial trucks. Truck traffic across the dam was halted after 9/11 due to security concerns. According to FHWA, more than 2,100 trucks are rerouted 23 miles over Highway 68 into Bullhead City. Future traffic is projected to reach 26,000 vehicles by 2027.
More than 500 accidents have occurred on the 3.4 mile stretch of highway including the dam since 1964, according to the FHWA. Between 1985 and 1991, 43 accidents involved one or more injuries and two were fatalities. Commercial trucks were involved in 96 accidents. Most of the accidents were caused by the sharp curves, narrow roadway, poor visual distance and slow travel speeds in the area.
The new bypass will shorten the distance across the dam to 5.5 miles and six minutes, without traffic. It will also protect Hoover Dam employees, visitors, power equipment and the Colorado River, he said.
Hoover Dam is the No. 1 national security priority of the Department of the Interior, according to FHWA. It is the only major highway in the nation since 9/11 that continues to be restricted.
Lake Mead supplies 29 million households with water each year, according to FHWA. The dam also supplies 4 billion kilowatt-hours of energy for 1.3 million people and provides flood control for more than 1.5 million acres of land in the U.S. and Mexico.
According to the FHWA, it wasn't until 1989 that the BOR, which operates the dam, created Colorado River Bridge Project Management Team. In 1993, the BOR withdrew as the lead agency on the project, after the bureau's emphasis changed from public works to water management. The bypass project was put on hold in 1995.
In 1997, work on the project was restarted under the leadership of Central Federal Lands Division of the Federal Highway Administration. Final design work on the bypass was completed in 2001 and construction of the bypass started in 2003 with the relocation of power lines, according to FHWA.
The Arizona approach to the bypass, including almost two miles of four-lane highway and a 900-foot bridge, was completed in 2004. The Nevada approach, which has more than two miles of four-lane highway and six new bridges, was completed in 2005.
Construction on the bridge itself started in 2005. A concrete arch design was chosen because of its strength and ease of maintenance, Zanetell said. Suspension span bridges, such as the Golden Gate Bridge, require more maintenance.
"Every bridge has its challenges," he said.
This bridge was no exception - nearly everything done during the construction of the bridge was the first of its kind. The extreme environment, with the heat and lack of humidity, was also a challenge, he said.
In 2006, high winds downed the 280 foot tall crane towers on either side of Black Canyon, which were used to transport bridge materials and people from one side of the canyon to the other. No one was hurt, but the collapse of the cranes slowed construction on the project until new ones were installed.
So far, the project has had only one fatality, Zanetell said.
In late November, Sherman Jones, 48, of Las Vegas was killed while adjusting a cable used to align the temporary concrete towers that support the arches.
The $114 million bridge is currently on budget and schedule to be completed in the fall of 2010, Zanetell said.
A pedestrian parking area, plaza and walkway along the side of the bridge facing the dam will also be constructed.
For more information on the Hoover Dam Bypass and progress on the Mike O'Callaghan-Pat Tillman Memorial Bridge, visit www.hooverdambypass.org.