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For other uses, see Demolition (disambiguation).
Demolition of the Old Myer Building, Perth, Western Australia Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use. For small buildings, such as houses, that are only two or three stories high, demolition is a rather simple process. The building is pulled down either manually or mechanically using large hydraulic equipment: elevated work platforms, cranes, excavators or bulldozers. Larger buildings may require the use of a wrecking ball, a heavy weight on a cable that is swung by a crane into the side of the buildings. Wrecking balls are especially effective against masonry, but are less easily controlled and often less efficient than other methods. Newer methods may use rotational hydraulic shears and silenced rock-breakers attached to excavators to cut or break through wood, steel, and concrete. The use of shears is especially common when flame cutting would be dangerous. The tallest demolished building was the 47-story Singer Building in New York City, which was built in 1908 and torn down in 1967-1968 to be replaced by One Liberty Plaza. Atomic demolition munitions are nuclear devices used for demolition or earthmoving purposes. As of 2009, they have never been used commercially or on a military deployment, though devices have been used to put out gas well fires as part of the Soviet test program. The Soviet Union tested the use of nuclear devices for mining and natural gas extraction on several occasions starting from the mid 1960s, as part of the Nuclear Explosions for the National Economy program. Tests for similar purposes were carried out in the United States under Operation Plowshare, but due to radioactive contamination caused by the tests, no commercial use was made of the technology. With today’s greater understanding of the dangers of radiation, it seems unlikely that nuclear devices will ever be used for non-military purposes. Operation Plowshare, better known as Project Plowshare, not to be confused with the anti-nuclear Plowshares Movement, was the overall United States term for the development of techniques to use nuclear explosives for peaceful construction purposes. The phrase was coined in 1961, taken from Micah 4:3 ("And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war any more"). It was the U.S. portion of what are called Peaceful Nuclear Explosions (PNE). The Soviet Union had a similar program of testing as well for many years. The Soviet program was titled Nuclear Explosions for the National Economy.
The 1962 "Sedan" plowshares shot displaced 12 million tons of earth and created a crater 320 feet (100 m) deep and 1,280 feet (390 m) wide.
From Wikipedia, the free encyclopedia : Demolition of buildings, earthmoving and drilling test |
