Lifting devices were mainly used for construction projects, but (later) also for the loading and unloading of goods, for hoisting sails on ships, and for mining purposes.
But, starting more than 5,000 years ago, engineers designed a collection of machines that greatly enhanced the lifting power of an individual or a group of people. Of course, this does not mean that one man can lift anything to any height, or that we can lift anything to any height if we just bring enough people together. The only advantage that fossil fuelled powered cranes have brought us, is a higher lifting speed. Nor is there a limit to the height to which this weight can be lifted. The only difference with contemporary cranes is that these machines were powered by humans instead of fossil fuels.īasically, there is no limit to the weight that humans can lift by sheer muscle power. The fact is, they had advanced machinery at their disposal. During the Middle Ages some 80 large cathedrals and around 500 large churches were built with a height of up to 160 metres - out of reach for all but the most recent top model crawler cranes (picture above, right).Ĭonsidering the type of cranes that would be needed today, one wonders how our forefathers were able to lift such impressive weights without the help of sophisticated machinery. The Egyptian pyramids rise up to 147 metres. The Alexandria lighthouse (3rd century BC) stood more than 76 metres (250 feet) tall.
Raising construction materials to impressive heights seemed to be no problem either. Only the most powerful contemporary cranes could handle stones of this weight (see the picture on the left, specifications here). The Colossi of Memnon, two statues of 700 tonnes each, were erected to a height of 18 metres and the walls in the Roman Baalbek temple complex (1st century BC) contain almost 30 monoliths weighing 300 to 750 tons each. The largest Egyptian obelisk weighed more than 500 tons and stands more than 30 metres tall, while the largest obelisk in the Kingdom of Axum in Ethiopia (4th century AD), raised up to a similar height, weighed 520 tonnes. The temple dedicated to Pharaoh Khafre in Egypt is made up of monolithic blocks weighing up to 425 tonnes. The gravestone of Theoderic the Great in Ravenna (around 520 AD) is a 275 tonne stone block that was lifted to a height of 10 metres. Occasionally, our forefathers lifted even heavier stones. Today, to lift a weight of 50 to 100 tonnes to these heights, you need a crane like this. The Roman Jupiter temple in Baalbek contains stone blocks weighing over 100 tonnes, raised to a height of 19 metres (62 feet). The 18 capital blocks of Trajan's column in Rome weigh more than 53 tonnes and they were lifted to a height of 34 metres (111 feet). The temple of Amon-Ra at Karnak contains a labyrinth of 134 columns, standing 23 metres (75 feet) tall and supporting crossbeams weighing 60 to 70 tonnes each. The majority of stones that make up the almost 140 discovered Egyptian pyramids have a weight of "only" 2 to 3 tonnes each, but all of these structures (built between 27 BC) also hold stone blocks weighing 50 tonnes, sometimes more. For quite a few construction projects in ancient history, this type of crane would be completely inadequate. The most common tower crane used in construction today has a lifting capacity of some 12 to 20 tonnes.
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