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Blast from the Past Engineering Marvel: The Hoover Dam

November 15th, 2012

Design, safety and economics were the top three priorities when building the Hoover Dam Bypass. It is one of the great structural engineering marvels of the world, and rightfully so, after taking nearly a decade to complete. The project stretched across two states, Arizona and Nevada, and included a 1,900’ crossing of the Colorado River.

Six contracting agencies were brought in to design and construct the bypass. The Central Federal Lands Highway Division (CFLHD) of the Federal Highway Administration awarded the contract to engineering firm HDR for design and management services. HDR led the way for subcontractors and engineering partners.

The key piece of this project is the Mike O’Callaghan/Pat Tillman Memorial Bridge, currently designated as the highest and longest arched concrete bridge in the Western Hemisphere, rising 890’ above the river.

The significance in the Hoover Dam Bypass is that its bridge is the first steel/concrete arch bridge constructed in the United States. The arch was created to compliment the landmark without ruining the beautiful tourist views of the Hoover Dam. The steel substructure allows for high intensity loads on the bypass. The two concrete arches are connected with steel struts, which provide a greater lateral strength in case of extreme winds or an earthquake. The bridge is also composed of trapezoidal steel box girders, integrated with post-tensioned concrete caps. These allow the roadway to serve as a lateral brace for the concrete columns, which are the highest in the world.

And of course, in the end, the final product looks beautiful, but the teams had to put up with some extreme challenges from Mother Nature. Rock had to be cut almost 100’ high, winds blew up to 70 miles per hour, and at times the temperature reached over 120 degrees.

One of the greatest outcomes of the project was the development of team building and partnerships between the engineers. Many had come from different backgrounds and skill levels, but all worked under the HDR umbrella to create the best possible product. The groups worked together to also grade and pave roadways, construct six other bridges, allow for wildlife crossings, drainage, lighting, utilities, traffic management systems, pedestrian accommodations, interpretive exhibits, high-voltage transmission line relocations, geotechnical engineering, surveying and mapping, and bypass corridor architectural design.

Contact The Talley Group for the top positions in civil engineering and work on life-impacting projects.

Modern Engineering Marvels

October 31st, 2012

Surely, design does make for beautiful structures. But at the basis of some world-renown structures are the foundations of sound, brilliant engineering. Here, we will go behind the scenes and look at some of the greatest modern engineering marvels around the globe.

1.Danyang Kunshan Grand Bridge

A relatively new structure, this bridge was opened on June 30, 2011. It is located on the rail line between Shanghi and Nanjing in East China. This is the world’s longest bridge at 102.4 miles, held up by 2000 pillars and steel cables. Over 10,000 workers helped to build the bridge, which took four years and cost $8.5 million dollars.

2.Hoover Dam

Still one of the reigning champions in engineering greatness after all these years, the Hoover Dam, located in the Black Canyon between Arizona and Nevada is one of the greatest structures in the United States. Many tourists from Las Vegas come to see the greatness built by thousands during the 1930s. The Hoover Dam was built to turn the Colorado River into a hydroelectric power source for the area. The project cost over 100,000 lives and turned the flowing river into Lake Mead.

3.Millau Viaduct Bridge

Located in Southern France, this bridge connects the highway between Paris to Barcelona crossing the River Tarn. Architects and engineers worked side by side to not only make this a functional, safe passageway, but one that reflected the beauty of the plateau environment as well. Cable-styled columns hold the span, using minimum material, giving a delicate effect. Each of its columns rises higher than the Eiffel Tower. The road bridge spans four lanes over the River Tarn. It is currently the tallest bridge in the world.

4.Floating Green Eco Cities

What used to just be a movie fantasy is now attempting to come to life through the Lilypad Project. The eco-city islands can accommodate more than 50,000 residents at a time and support biodiversity. Collecting pools assemble water and filter it for use and solar panels provide energy.

5.Three Gorges Dam

Located in China, this dam is the result of the country’s hydro-engineering ambition. The dam spans the Yangtze River, and is the world’s largest power station in terms of capacity. The dam was not only intended to produce electricity, but decrease flooding in the area as well. However, the project has been plagued with problems since construction began in 1992. Over 16 million tons of concrete were poured into the giant barrier, creating a reservoir stretching almost the length of Britain. Besides the massive expense, over 1.4 million people have been displaced due to the project and still over 1,000 towns and villages have been flooded.

Contact The Talley Group to participate in some of the greatest engineering jobs in the world.

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