Building Pyramids: Number of People

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Many hypotheses about the way the great pyramid was built suggest vast armies of labourers working for 10s of years, or impossible machines that defy every demonstration and measurement of the physical world.

Most of these hypotheses are based on vivid Victorian imaginations that have not been properly scrutinised or tested.

Estimates

The great pyramid is built from aproximately 2 million blocks of stone.
Each block averages 0.9m x 1m x 1.2m
This stone has a density of 2.563kg/m^3 (160 lb / cu ft)
So each stone averages 2768 kg (2.5 tons)

Calculations

Most big building projects, such as building the medieval cathedrals, used a constant, skilled work force over many years. Let us assume that the great pyramid was no different. So let us assume a fairly constant skilled workforce working 300 days per year, and a target of 10 years to completion. There is no reason to vary the rate of building as the pyramid rises.

In 10 years we have 3000 working days.
So each day we need to cut, move and place 2 000 000 / 3000 = 666 blocks per day.
Let us assume 700 blocks per day to allow for some wastage.

I am going to use the figures for cutting stone by hand provided by the Beer Quarry Caves in Devon UK. Here it took 10 hours for one man to cut a 4 ton block of stone.
It seems a reasonable deduction that on average 1 man will be expected to cut 1 block of stone of 2.5 tons as his days work - an easy measure of whether he has worked well that day!

So 700 blocks per day requires 700 men as cutters in the quarries.
100 men each loading and transporting 7 blocks per day and removing debris.
10 men each preparing 70 saws per day.

If I were building the pyramid I would hope to cut the stone from a quarry from a rock face slightly uphill of the building site, even up to 10 miles away, so that I can build a wooden sledge track with a downhill slope to the quarry site. Even at that distance a team of one man and a pair of oxen should haul 3 blocks per day.
So for transport to the building site we need 250 men.

Lifting the stone up the sloping face of the pyramid using the Herodotus lifting engine requires a team of 6 people pulling the levers to lift a block 1m in 10 seconds with an expenditure of 500w of energy each.

If we assume that they are not being flogged to death, take a reasonable rest between each block and we use 10 lifting engines side by side, then each engine series needs to lift 70 blocks per day.

This is the one area where the workforce has to increase as the pyramid gets higher, because we are using a team of 60 people for every metre it increases in height, but this is not skilled labour - just pull and release the levers, then sit down and rest for 5 minutes.
On the working level we need 100 people to move and place the blocks, 10 people to move and rebuild the sledge tracks and perhaps another 20 people to lower the sledges back to the ground - but the sensible way would be to lower the sledges on ropes attached to the rising sledges, so reducing the energy required for both operations.

Add another 10 carpenters to maintain the tracks.

Add another 300 people to do all the checking, supervising and procurement

And we have a grand total of 2000 people to build a pyramid up to the 10m level and then an extra 60 people for each metre extra height.

Not a vast number!! and far more likely to be specialist workers paid well on a year round basis.

This information is copyright Peter Thomson 2001-2004

 ancients peoplepyramid
 
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How did they cut the granite? Why were their cuts .03 variance? How did you conclude a average of 2.5 tons per stone? The stones were 2-70 tons. How did they make the curveture match the earth? How did they know the earth was round

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 ancients peoplepyramid
  steve parsons
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plumb square is our old masons tool (befor someone invented the bubble) as the site is flattened off this would always give a reading following the curviture

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 ancients peoplepyramid
  Hannah Klar
Hi peter i have a question for you. How many rooms are in the pyramid

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 ancients peoplepyramid
  stan taylor
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What about victualling,cooking,transport of food,and materals for maintainance,medical care,animal feed and care, fuel etc etc Remember the old adage "It takes 3 people to keep one soldier in the field. Obviously you are not a Practical man Peter

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Copyright Peter Thomson 2012-May-19