I am pleased to welcome you to my personal blog, which I started in March 2009. I first became interested in blogging about five years ago, using old "blogger.com", which was cumbersome to use and I never mastered. About a year ago I discovered that Google had bought "blogger.com" and had revised it considerably, making it fun to use, so much so that I have devised at least 15 blogs on various subjects and frequently add posts and Gadgets to them.

Monday, November 9, 2009

Hoover Dam Bypass and Bridge

The New Hoover Dam Bypass – Wider View
Posted in Crazy Pictures, Picture Worth 1000 Words • Tags: Hoover Dam Bypass • Author: HART (1-800-HART)

call HART crazy .. but


THE WIDER VIEW: Taking shape, the new bridge at the Hoover Dam
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 takes shape.

The bridge will carry a new section of US Route 93 past the bottleneck of the old road which can be 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 Mike O’Callaghan-Pat Tillman Memorial Bridge
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 Hoover Dam
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.

Hoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Arizona and Nevada. When completed in 1936, it was both the world's largest electric-power generating station and the world's largest concrete structure. It was surpassed in both these respects by the Grand Coulee Dam in 1945. It is currently the world's 35th-largest hydroelectric generating station.[4]
This dam, located 30 mi (48 km) southeast of Las Vegas, Nevada, is named after Herbert Hoover, who played an instrumental role in its construction, first as the Secretary of Commerce, and then later, as the President of the United States. Construction began in 1931, and was completed in 1936, more than two years ahead of schedule. The dam and the power plant are operated by the Bureau of Reclamation of the U.S. Department of the Interior. Listed on the National Register of Historic Places in 1981, Hoover Dam was designated a National Historic Landmark in 1985.[3][5]
Lake Mead is the reservoir created by the dam, named after Elwood Mead, who oversaw the construction of the dam.

The Incredible Hoover Dam Bypass Bridge Under Construction
Published by R J Evans
June 23, 2009, Category: Engineering
Announced in 2004, the Hoover Dam Bypass Bridge has been five years under construction. Due to be completed in 2010, the bridge has slowly been taking shape. Here, with some amazing photographs is a record of this incredible bridge as it nears completion.
The people of Arizona and Nevada are patient folk. Since 1935 they have seen their local roads slowly but surely become more and more congested, most certainly at one particular point. The Hoover Dam. Since its inception it has been an important connection between the two states in terms of commerce and simply for the making the journey between the two considerably quicker. Let’s start with a money shot – even though you ain’t seen nothing yet.

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A 2008 shots gives the imagination something to work on. As the Hoover Dam became more and more popular with tourists the local roads began to get more congested than people could really put up with. Their solution? Harking back to the huddled masses days when America really was considered to be the land where everything was super-sized (and not just the fast food) the good citizens of Arizona and Nevada decided to build a bridge. Not just any old bridge though, this one would have the longest concrete arch in the US. The arch would ultimately be finished in August 2000 – and you can see it in its entirety here.

Read more in Engineering
« Spectacular Dams Around the WorldDifference Between Diesel and Gasoline Engines »
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In 2007, the tower structures, these known as approach spans, are beginning to take shape. It is known, in the briefest of terms as the Hoover Dam bypass and this much is true. There will be seven approach spans all in all, two on the Arizona side and five on the Nevada side. The bridge is enormous, but its proximity to the dam is less than half a kilometer. The longer, more proper and formal name is the Mike O’Callaghan-Pat Tillman Memorial Bridge. Perhaps it is already known as The Mike and Pat locally. O’Callaghan was the Governor of Nevada in the nineteen seventies as well as a veteran of the Korean War. Tillman is by far the more controversial choice. He gave up a millionaire lifestyle and superstar footballer status to serve in the US Army in Afghanistan where he was killed in 2004. His death has been subject to military investigations and more than the occasional conspiracy theory.

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Back to 2005 and the bridge is in its infancy. It has a way to go, even yet, in its construction, even though the most recent pictures see the span almost conquered by one of the most amazing engineering feats of our times. It will cost a pretty penny, of course; estimates have it at upwards of two hundred and fifty million dollars. Patience, however. Try and resist the urge to scroll down and take in the images, if you… too late.

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It won’t exactly be a slim bridge, either. It and the other new sections of Highway 93 will have two lanes going each way over its five hundred and seventy five meter span. It may not be an idea to look down either if you suffer from vertigo. The road itself will be a dizzying two hundred and fifty six meters above the Arizona River. Although people will still be able to park and walk across it (if they dare) drivers will not be able to see the Hoover Dam. It is too close and too below to be seen by them. The project suffered a serious setback in 2006 when four cranes collapsed. This caused a massive two year delay while the project recovered. It is now back on track and the next in this series of articles can be found here.

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At night, in 2008, the construction work seems like some vast drawbridge in to some dark post apocalyptic fortress. Behind it, the Hoover Dam. Iconic as the dam is, the bridge itself will become an important route between two equally iconic American cities, Phoenix in Arizona and Las Vegas in Nevada. Since the Dam’s completion both cities have seen their population sky rise (perhaps the bridge is a good metaphor for the burgeoning number of their citizens).

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By April of 2009 the bridge begins to look like a bridge – not to state the obvious. Suddenly, in the space of months a real shape begins to emerge. It looks as if plans are on schedule for the bridge to serve as the successor to the old road. Highway 93, which was as good as highways got back in 1935 is simply too old and, well, curvy to be adequate in this day and age for twenty first century traffic. Plus of course, it only has two lanes (that is counting both directions).

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A closer look at the arches gives the onlooker a greater impression of the sheer scale of the project. Take a look at the moveable platforms where brave people perform their duties each day. A certain day in the September of 2001 made things worse for those who rely on the original road across the dam as a transport link. After the air attacks on the American mainland, no trucks have been allowed over the dam for fear they could be packed with high explosive. Instead the trucks have been sent south to a crossing near Laughlin (on the Nevada side). More disruptions, albeit for a very good security reasons. When you figure that there will be almost twenty thousand cars and trucks using the new bridge every day the enormous costs – and the security concerns – begin to make a lot of sense.

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Let us take to the air to see the bridge from a real vantage point and ponder the simply awesome highlights of the project. To begin with it will eventually take the removal and embankment of over three and a half million cubic yards of earth. The bridge itself will be made from two hundred and forty three million tons of concrete. The steel used to reinforce the concrete would, if put on a set of scales, weigh sixteen million pounds (some set of scales!). Plus it has brought many, many jobs in to the area, with over twelve hundred people being involved in its construction.

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June 9, 2009 and the arch edges even closer to completion. The arch is more than fifty percent complete and it is hoped that the two sides will meet in the Fall of this year. Below, even more recent on June 18. What kind of party will be held on the day the two parts of the arch meet is anyone’s guess, but it is likely to be the biggest since the end of Prohibition. It can only be hoped that none of the revellers gets too tipsy and ends in the Arizona River.

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It is hoped that the bridge will be complete some time in 2010. When it is complete it will look like something out of the space age (oh, shucks, yes, that’s our era after all). The impression below, with no disrespect to the artist (but one suspects he once worked for Gerry Anderson), gives away little of the grandeur and majesty that the final, finished bridge will possess in (millions of) tons.

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The next in this series of articles, which covers July – October 2009 – when the arch becomes free standing can be found HERE.

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