By the summer of 1933, engineers broke the Hoover Dam into hundreds of independent concrete blocks c

追加: 2026-05-20

[00:00:00]By the summer of 1,933, engineers broke the Hoover Dam into hundreds of independent concrete blocks called columns, each roughly 7.6 m squared >> [music] >> and separated by tar paper to allow independent thermal expansion and contraction. Each column contained roughly 300 m of thin steel cooling pipe threaded through it. And when the arithmetic was finished, the total length of cooling pipe embedded in the dam came to approximately 1,000 km.