Science Fix | Hoover Dam Construction

Описание: Back in 1935 the Marèges Dam proved that engineers could divert rivers to build powerful dams. But to break through the 1,000 megawatt mark, American engineers building the Hoover Dam had to take their building material to the limit.

In the 1930s the USA decided to tackle one of their big economic problems. The cities in the Western United States couldn’t grow because the lacked both water and power. To break the deadlock engineers began work on the world’s biggest dam. It would contain more concrete than any other construction project before it, but as concrete sets, a chemical reaction causes it to heat up. This created a problem for the Hoover Dam’s engineers.

If the concrete of the Hoover Dam was poured in one g, the concrete on the outside would’ve cooled and hardened first, while in the core of the dam the concrete would’ve stayed hot and tried to expand. This could stress the concrete and cause it to crack. So the engineers cast the concrete for the Hoover Dam in small individual blocks. As the concrete in each block cooled it shrank, but it didn’t crack. The contraction left small gaps between the blocks which engineers filled with cement, but this clever design didn’t solve all the problems

Engineer Frank ‘Hurry-Up’ Crowe embedded over 950 kilometres of steel waterpipes into the concrete of the Hoover Dam. He built a huge water chilling factory, where he cooled river water down to 4 degrees and then shot it through the pipes into the hot concrete. This shortened the cooling time from 125 years to only 22 months.

The Hoover Dam stored 35 billion cubic metres of water and at the time generated more power than any other dam in the world. With this magnificent arch-gravity dam behind them the cities in the American west could finally begin to thrive

Watch the complete documentary here –    • Mega Dams – Hydroelectric Evolution – Big ...  

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