Wednesday, July 4, 2012

Mike O'Callaghan-Pat Tillman Memorial Bridge--Truly Beyond My Realm Of Comprehension

The Mike O'Callaghan-Pat Tillman Memorial Bridge is named after two-term Nevada Governor and decorated Korean war veteran Mike O'Callaghan and Pat Tillman, the Arizona Cardinals linebacker who joined the U.S. Army after 9/11 and was killed in Afghanistan.
The new bridge over the Colorado River at Hoover Dam...
Meet America's Newest Wonder

You're about to see a remarkable time-lapse presentation chronicling
the 5-1/2-year construction of the new bridge that now towers over the
Colorado River and Hoover Dam.

An instant tourist attraction, it stands 89 stories above the Colorado
River, commanding unparalleled views of Hoover Dam and Lake Mead.
It is the highest and longest concrete bridge in the Western
Hemisphere and boasts the world's tallest concrete columns of any kind.

Dedicated in October 2010, it provides a quicker and safer drive
between Phoenix and Las Vegas, eliminating the 75-mile detour and long
checkpoint jam-ups that ensued when traffic was banned across Hoover
Dam for security reasons.
What you will see is how the massive concrete arch begins to form
simultaneously from both sides of the river...and the amazing joining
of both halves of the arch coming together perfectly almost 90 stories
above the blue waters of the Colorado.

Keep in mind that all this was being done in extreme climatic
conditions where summer heat can exceed 120-plus degrees!

For that reason, much of the concrete work had to be done at night.

Furthermore, liquid nitrogen had to be injected into each load of
concrete to keep the pouring temperature at 80 degrees or less to keep
the concrete from drying too fast and cracking.

Imagine the planning, the precision, the engineering nightmares.

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