Thursday, October 21, 2010

The Hoover Dam Bridge [updated]

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The Hoover Dam is one of the most impressive human constructions on the planet. (Yes, yes, I know it was a government make-work project, but still ... )

Perhaps one of the few things to top it is this, the new 1,060 foot twin-rib concrete arch bridge over the Black Canyon, about 100 feet south of the Hoover Dam, due for completion in December.

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If swearing at sheer awesomeness was ever justified, this bridge would be it.

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The pics are from a series of Bridge Folios by Jamey Stillings of the bridge under construction that you should really examine in depth.

While listening to Bob Mould.

UPDATE: Stephen Hicks sees similarities between this bridge and something by Michelangelo …

And he links to the description of the bridge’s construction at Popular Science:

_Quote Temperatures upward of 115°F, winds capable of felling cranes, an 890-foot drop below: ‘Inhospitable’ doesn’t begin to describe conditions at the Colorado River’s new Mike O’Callaghan–Pat Tillman Memorial Bridge.
    A 1,900-foot span designed to divert traffic from the narrow, switchback-laden road across the Hoover Dam, it will be the longest concrete arch bridge in the Western Hemisphere when it opens next fall, with 106 segments of ultra-high-strength concrete forming a twin-rib arch. Workers scaled the canyon’s walls, digging notches for concrete foundation columns. To construct the 1,060-foot-long arch, they cast 24 feet of concrete at a time, while a separate, temporary cable-stayed bridge held up the unfinished ends until the gap was closed this year.

It’s that cable-stayed temporary bridge that gives the new bridge so much of its drama.

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6 Comments:

Anonymous The Gantt Guy said...

Truly an engineering marvel, PC. The irony is in the purpose of the bridge. It was built primarily to insure against a terrorist attack on the dam itself, but its location looks to me to be a pretty good launching spot for an RPG or some other shoulder-mounted weaponry.

10/21/2010 12:24:00 am  
Anonymous Robert Winefield said...

Gantt Guy,

I stood on the Hoover Dam and observed this beautiful creation being built and I can you say with the absolute certainty of an eye-witness with photographic evidence to back him up - that you are talking out of your arse.

(1) The bridge was built to alleviate the traffic problems caused when you have a major interstate highway crossing a 2 lane Dam packed with tourists that spans one of the most visually striking geographical features I've ever seen.

(2) If you could unhitch a launch tube for a gas-disseminating missile before you got turned into a human colander by the Dam security, it would be a bloody miracle.

First, this dam & bridge is within spitting distance of a major USAF airbase (Nellis AFB - home to more USAF squadrons than any other AFB in the USA. It is also a major USAF pilot training facility). The American's don't protect these with Doughnut quaffing Rednecks.

Second, it is also within spitting distance of one of the USAs most iconic cities and a haven for every type of vice known to man. The police in this region are very experienced in dealing with scumbags.

Not only that, it marks the boundary between Arizona and Nevada.

Taking a leak on the wrong part of that dam puts you in jeopardy of committing a crime that crosses state lines.

So good luck avoiding observation by tourists (thousands visit the Dam every day) as you wander around with an RPG launch tube shoved down your shorts.

Good luck evading the FBI, Arizona & Nevade State troopers, two sets of county Sherriffs and the Los Vegas PD. Not to mention the Park Rangers (who God-bless them, also pack heat) who patrol not only the Dam but the approaches to it also.

(3) Good luck bringing the bridge down with a single RPG round. These structures span one of the world's wildest rivers. They aren't built of Lego.

(4) And even if they did make a man-portable missile big enough for the job. Good luck hitting the Bridge from the Dam. It's at least a 1,000 yard direct shot at a 60 degree elevation from the Dam -- which traverses a steep narrow valley.

For your would-be Rocket marksman that means he not only has to account for the effect of stealth, opposition forces but also gravity, distance and wind.

As the Tui billboards say: Yeah Right!

10/21/2010 04:25:00 am  
Anonymous James Stephenson said...

I really must get my record player hooked up, I've got that album on vinyl...

10/21/2010 08:29:00 am  
Anonymous The Gantt Guy said...

Robert, more than happy to be put back in my box on this one. Most definitely talking out of my arse (hey, maybe I should run for Parliament). Not an engineer, and wouldn't have the first clue about either of these structures (apart from they are a testament to man's creative genius). Never been there, so wouldn't know the first thing about the security arrangements. Just commented after looking at the photos and reading an article.

10/21/2010 08:41:00 am  
Blogger Jeff Perren said...

A well designed bridge is always one of the most beautiful creations of man.

There are many examples over the centuries, including the Ancient Roman-era Alcantara in Spain, to the Clifton Suspension Bridge created by Brunel, to Lord Foster's Millau-Viaduct bridge, and dozens more.

This is one example where people really do far too often take something heroic for granted, because the art has achieved such a high level.

Nice to see another one going up, and so visibly and with good publicity.

10/21/2010 01:48:00 pm  
Blogger Dinther said...

Those are the most beautiful photos I have ever seen. They draw me in but I can get hold of what I see. So laser sharp and compelling.

Not even sure they are photos.

I see I can order prints but they don't date to list the price. Must be expensive.

Magnificent and then some

10/21/2010 09:04:00 pm  

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