Building the Hoover Dam

[Music] on its completion in 1936 this was the largest concrete structure ever built the incredible feat of engineering played a critical role in the development of the American Southwest during the early 20th century providing flood management's hydroelectric power and securing a reliable source of water for millions this is how the Hoover Dam was built with plans around since 1900 to harness the power of the mighty Colorado River it wasn't until 1928 that the United States Congress authorized the project and initial surveying began with the onset of the Great Depression just a year later the project was seen as a way for the government to provide much-needed jobs in the American Southwest which had been experiencing a population boom prior to the stock market crash located 26 miles southwest of Las Vegas on the Nevada Arizona border the project required a vast number of workers and their families to relocate and an entire new town was established owned and run by the government Boulder City was to be a model for the rest of the country to follow in the dark times of the depression to drive the project's progress president Hoover ordered construction of the dam to start in May 1931 before the necessary infrastructure at Boulder City was in place and many workers lived in temporary tents in what became dubbed rag town to escape the harsh living conditions many workers began to frequent the then small outpost of Las Vegas driving significant growth and earning its reputation for gambling and adult entertainment though living conditions were poor work began on diverting the Colorado River so the dam could be constructed on the dry riverbed to divert the water flow for 56 foot 17 meter wide diversion tunnels to on each side of the river were bought through the canyon using nothing more than dynamite followed by workers using pneumatic jackhammers excavated rock was then dumped into the Colorado River creating a cofferdam the forced water to flow through the newly constructed tunnels a second coffer dam downstream prevented water flowing back into the construction site and formed an area that could be pumped dry exposing the riverbed the Hoover Dam employs a gravity art design and is held in place by the weight of its concrete together with the pressure of the water it holds forcing it into the canyon floor and walls such a principle required the canyon surfaces to be smooth as one of the first activities to prevent leaks it was during this phase of the project that the first hard hats began to be used workers dipped their hats in tar and let it harden protecting them at least to some extent from falling debris seeing their success the project's leaders quickly ordered thousands of these hats and mandated their use by the workers in 1933 some 18 months ahead of schedule the first concrete pours began on the dam as concrete gives off heat and contracts as it cures a project on the scale of the Hoover Dam would have taken more than 125 years to harden if poured in a single continuous pour and structural weaknesses would have caused the dam to crack under its own weight instead the site was divided into a series of rectangular molds some as large as 50 square feet or 15 square meters in size these molds were fitted with a series of steel pipes that carried river water through them allowing the concrete to cool and hardened much faster than if it was left to do so alone in the heat of the desert once the concrete had hardened and stopped contracting the pipes and hairline cracks between neighboring blocks were filled in with grout and a new layer of molds was placed on top this process was repeated time and again to build the dam walls as the dama steadily rose getting the concrete to where it had to go before it began to harden started to pose a significant challenge to overcome this an ingenious system of overhead cables that carried buckets of concrete from specially built concrete plants on the Nevada side of the dam to the required location on the construction sites was used in total eighty-seven point five million cubic feet of concrete and some 582 miles of cooling pipes were used in the construction of the dam by 1935 two years ahead of schedule the 726 foot high dam was complete and the river dye version tiles were sealed shut allowing the Colorado to begin flooding the canyon behind the structure and creating the reservoir we know today as Lake Mead fit out of the adjacent power plant and its associated infrastructure took place in parallel with construction of the main structure and the dam began generating electricity at the end of 1936 today this remarkable infrastructure project has an average output of 4.2 billion kilowatt hours and provides water and electricity to millions across the southwestern United States an economic catalyst to an entire region of North America and a powerful example of the impacts that our industry can have if you enjoyed this video and would like to get more from the 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Keywords: BIM, B1M, TheB1M, Construction, The B1M, fred mills, architecture, history, documentary, USA, united statesof america, dam, hoover dam, colorado river, nevada, arizona, lake mead, las vegas, great depression, infrastructure, hoover, worlds largest, innovation, building, american infrastructure

Id: n9Gy_1Ppw5U

Length: 6min 50sec (410 seconds)

Published: Wed Aug 15 2018