Wednesday, March 4, 2015

The king of bridges

Las Vegas is crammed with eye-popping, man-made wonders, but a fake Paris, Rome or Venice pales in comparison to this engineering feat.   The new Mike Callaghan-Pat Tillman Memorial Bridge spans the Colorado River between Nevada and Arizona. At nearly 900 feet above the Colorado River, it is the world's highest concrete steel composite arch bridge and the second highest bridge in the U.S.

Construction of the bridge itself began in February 2005 and the route opened to vehicle traffic on October 19, 2010. The Hoover Dam Bypass project was completed within budget at a cost of $240 million.
To put that in perspective, the projected cost of Alaska Way Viaduct/Big Bettha project is 4.5 BILLION dollars and still counting.
The composite design, using concrete for the arch and columns with steel construction for the roadway deck, was selected for schedule and cost control while being aesthetically compatible with the Hoover Dam. I think the engineers succeeded beyond their wildest dreams.

Photo credits to John. I was too busy gawking and clutching the handrail for dear life.

View from the parking lot on the Arizona side of the river.

The start of the pedestrian walkway along the highway. A tall concrete barrier prevents motorists from looking down and getting distracted. No kidding.
The dizzying view from the middle of the bridge looking down on massive Hoover Dam.
The old highway US 93 still crosses the top of the dam, now used mostly by tourists. It's hard to believe massive numbers of cars and trucks once went creeping along these hairpin curves.
It's also hard to believe how fast our little vacation was over.  Thanks again Marji for being the best local tour guide!  We flew back to Seattle yesterday afternoon after a small delay at the airport.  Right before take-off, the plane headed back to the gate for some last minute mechanical tweaks, one involving duct tape (don't ask.)  We made it home safe and sound.

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