Hoover Bypass

[jay]

Who wants to be the first one to test drive this bridge?

Creeping closer inch by inch, 900 feet above the mighty Colorado River , the two sides of a $160 million bridge at the Hoover Dam slowly take shape.
The bridge will carry a new section of US Route 93 past the bottleneck of the old road which can be seen twisting and winding around and across the dam itself.

When complete, it will provide a new link between the states of Nevada and Arizona .  In an incredible feat of engineering, the road will be supported on the two massive concrete arches which jut out of the rock face.

The arches are made up of 53 individual sections each 24 feet long which have been cast on-site and are being lifted into place using an improvised high-wire crane strung between temporary steel pylons.
 

 
The arches will eventually measure more than 1,000 feet across.  At the moment, the structure looks like a traditional suspension bridge.  But once the arches are complete, the suspending cables on each side will be removed.  Extra vertical columns will then be installed on the arches to carry the road.   
The bridge has become known as the Hoover Dam bypass, although it is officially called the Mike O'Callaghan-Pat Tillman Memorial Bridge, after a former governor of Nevada and an American Football player from Arizona who joined the US Army and was killed in Afghanistan.
Work on the bridge started in 2005 and should finish next year.  An estimated 17,000 cars and trucks will cross it every day.

The dam was started in 1931 and used enough concrete to build a road from New York to San Francisco .  The stretch of water it created, Lake Mead , is 110 miles long and took six years to fill.  The original road was opened at the same time as the famous dam in 1936.
 
An extra note:  The top of the white band of rock in Lake Mead is the old waterline prior to the drought and development in the Las Vegas area.  It is over 100 feet above the current water level.

[Evilmonkey]

I seen this bridge last fall on a helicopter tour of the Grand Canyon...Very impressive from the sky, I am sure it will cut down on travel time between the two states.

[Ron (r273)]

They have made a little progress since 07.

[mike]

went there last aug 09/ they sure got a lot done since then wow.is the boarder going to be on top?

[Op-Bell]

It's opening to traffic this week, and the pedestrian walkway has been open for a few days already.

[StatFreak]

What will happen to the dam? Will it be closed to vehicular traffic or will tourists still be able to drive across?

[Op-Bell]

What will happen to the dam? Will it be closed to vehicular traffic or will tourists still be able to drive across?

I don't know, but I imagine you'll still be able to drive cars across it, otherwise you won't be able to get to the visitor's center from the AZ side without about a 10 mile detour. Since the visitor's center cost more than the original cost of the dam, they'll want to keep the numbers up.

[Neonkiss]

Oct 21st 2005
I took this pic during a trip.
They had the first cables strung across the river and you can see the base of the arch columns  in the upper left hand corner.

[Buzz]

This is a bridge in France.

[jay]

The Hoover Bypass bridge was engineered in Japan and all of the steel imported from their as well.
So much for a US Infrastructure project.

[knagl]

What will happen to the dam? Will it be closed to vehicular traffic or will tourists still be able to drive across?

From what I've read, cars will no longer be permitted to drive across the dam (security concerns, although I don't think anything short of a nuclear bomb could bring that dam down).  I know there's a small parking area on the Arizona side of the dam that I imagine interested visitors from that side could park at and walk across the dam to the visitor's center.

[Op-Bell]

I don't think anything short of a nuclear bomb could bring that dam down

Actually it turned out not to be that difficult to demolish a large dam, as was demonstrated in WW2 against the Mohne dams in Germany. 3 tons exploded 150 feet under water against the face did the trick. It wasn't the explosive alone that did it, it was the tipping action of millions of tons of water entering the base of the dam when the face was broken. They're quite correct to worry about the Hoover dam - all a bad guy would need to do is roll a suitable quantity of explosives off a truck over the parapet on the upstream side, with a depth fuse.

[brichter]

They're quite correct to worry about the Hoover dam - all a bad guy would need to do is roll a suitable quantity of explosives off a truck over the parapet on the upstream side, with a depth fuse.

It'd be more fun to drop it like they did against the Mohne. That's an excellent story...

[StatFreak]

I don't think anything short of a nuclear bomb could bring that dam down

Actually it turned out not to be that difficult to demolish a large dam, as was demonstrated in WW2 against the Mohne dams in Germany. 3 tons exploded 150 feet under water against the face did the trick. It wasn't the explosive alone that did it, it was the tipping action of millions of tons of water entering the base of the dam when the face was broken. They're quite correct to worry about the Hoover dam - all a bad guy would need to do is roll a suitable quantity of explosives off a truck over the parapet on the upstream side, with a depth fuse.

They're quite correct to worry about the Hoover dam - all a bad guy would need to do is roll a suitable quantity of explosives off a truck over the parapet on the upstream side, with a depth fuse.

It'd be more fun to drop it like they did against the Mohne. That's an excellent story...

Is that the film called The Dam Busters?  I haven't seen it in years, but it was an exciting film, as I recall.

[Op-Bell]

Is that the film called The Dam Busters?  I haven't seen it in years, but it was an exciting film, as I recall.

It is; it's a 1955 black and white. I saw it when I was very young and I've never forgotten the flak tracers coming at the aircraft. A remake is in progress by Peter Jackson - I recall there was some dispute about what they would call Guy Gibson's black dog, which in the original was called a word that rhymes with Trigger. For those unfamiliar with the story, the bombs had to skip across the surface to get past torpedo nets designed to prevent exactly this sort of thing. I wouldn't be surprised if there are nets defending the Hoover Dam also.

Ah, some kind soul has posted the flak scene to YouTube.

<a href="http://www.youtube.com/v/lCRIsjJFRNo&rel=0" target="_blank">http://www.youtube.com/v/lCRIsjJFRNo&rel=0</a>

[brichter]

Yup, the movie was good, and History Channel did a couple of pieces on the subject; one the story of Operation Chastise, and one on the technology of the bombs themselves (they rotated at 500 rpm reverse of the direction of flight to cause them to skip across the surface).

[StatFreak]

Is that the film called The Dam Busters?  I haven't seen it in years, but it was an exciting film, as I recall.

It is; it's a 1955 black and white. I saw it when I was very young and I've never forgotten the flak tracers coming at the aircraft.
...

I was also a child when I saw it. I remember being impressed with the ingenuity of the design of the bombs, and the intensity of those bomb run scenes.

[Op-Bell]

I came across this article today about the construction of the French bridge Buzz mentioned, the Millau Viaduct. It's interesting that in the pic he posted it appears to be curved - that must be an effect of the wide angle lens, coz it looks straight here.

[Buzz]

OP  I got it in a email a couple of years ago.  Did you read that they removed those Red towers after completion? 

[Op-Bell]

Yes, they were just there to support the deck while it was being pushed into position. I was surprised to see that the suspension towers and wires were built with the deck, pushed out also and bolted to the piers afterward. Civil engineering is very interesting.

[Jim]

as of 2-25-2011  traffic was still allowed to cross the dam.  this is the view of  the new bridge  as you look at it from the roadway atop of the dam.

Have been here several times, everytime is as great as the previous visit, what those people accomplished and overcame to construct this dam was truly a credit to them.

Jim

[brichter]

Went across the new span back in January, I wasn't impressed with the view. You can't see much from the roadway as the walls are too high on the sides.   






Of course this is probably to keep the rubberneckers from driving off the roadway into the river as they're checking out the scenery...

[knagl]

Isn't there a pedestrian walkway, though, so you can park beyond the bridge and walk back on to it?  (...and see the scenery without worrying about driving off the road!) 

[Jim]

we never drove across the bridge, however , on the approach to the dam parking area just after the security check point there is a parking area just for people who want to walk up to the bridge. you have to climb several sets of steps to get up to the walkway.

Jim