Egyptian pyramid construction techniques

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See also: Egyptian pyramids

Two major theories surround the construction of the pyramids of Egypt. The first theory, suggested by the Greeks, posits that slaves were forced to work until the pyramid was done. Current consensus among Egyptologists also is that the head of the Great Sphinx at Giza is that of Khafre, who is believed to have built the pyramid next to Khufu's in the Pyramids of Giza.

[edit] Third and Fourth Dynasties

During the earliest period, pyramids were constructed wholly of stone. Locally quarried limestone was the material of choice for the main body of these pyramids, while a higher quality of limestone quarried at Tura (near modern Cairo) was used as the outer casing. Granite, quarried near Aswan, was used to construct some architectural elements, including the porticulis (a type of gate) and the roofs and walls of the burial chamber. Occasionally, granite was used in the outer casing as well, such as in the pyramid of Menkaure. In the early pyramids, the layers of stone (called courses) forming the pyramid body were laid sloping inwards; however, this configuration was found to be less stable than simply stacking the stones horizontally on top of each other. The Bent Pyramid at Dahshur represents the transition between these two building techniques; its lower section is built of sloping courses, while in its upper section the stones are laid horizontally.

[edit] Middle Kingdom and onward

During the Middle Kingdom, pyramid construction techniques changed again. Most pyramids built at this time were little more than mountains of mud brick encased in a veneer of polished limestone. In several cases, later pyramids were built on top of natural hills to further reduce the volume of material needed in their construction. The materials and methods of construction used in the earliest pyramids have ensured their survival in a generally much better state of preservation than is the case with the pyramid monuments of later pharaohs.

One of the major problems faced by the early pyramid builders was the need to move huge quantities of rock. While 80 men can drag a 2.5-ton block of stone on a sled, as depicted in carvings in some later Egyptian tombs, this brute-force method was not very efficient. Dr R H G Parry^[1] has suggested a method for rolling the stones, using a cradle-like machine that had been excavated in various New Kingdom temples. Four of those objects could be fitted around a block so it could be rolled easily. Experiments done by the Obayashi Corporation, with concrete blocks 0.8 m square by 1.6 m long and weighing 2.5 tons, showed how 18 men could drag the block over a 1-in-4 incline ramp, at a rate of 18 meters per minute. Vitruvius in his books of architecture^[2] described a similar method for moving irregular weights. While it is unknown if the Egyptians used this method, the experiments show it could have worked. While Egyptologists maintain this, and indeed the pyramids were mostly made of 2.5 ton blocks, there were the 15-ton and the few 70-ton blocks that they do not mention.

As the stones forming the core of the pyramids were roughly cut, especially in the Great Pyramid, the material used to fill the gaps was another problem. Huge quantities of gypsum and rubble were needed. The filling has almost no binding properties, but it was necessary to stabilize the construction. To make the gypsum mortar, it had to be dehydrated by heating, and this required a lot of wood. The findings of the David H. Koch Pyramids Radiocarbon Project^[3], suggest that Egypt had to strip its forest and scrap every bit of wood it had to build the pyramids of Giza. When the project tried to date several pyramids using the carbon extracted from the filling in the pyramids' core, they found the dates spanned almost 300 years, implying that old wood was used for some parts of the pyramids. This was seen only in the Old Kingdom pyramids, especially from Djoser to Menkaure. This could mean that later pyramids were built smaller out of necessity, due to the severely depleted state of Egypt's forest resources.

[edit] Construction method theories

Example of a large straight ramp

From left to right: Zig-zagging ramp (Holscher), ramp utilizing the incomplete part of the superstructure (Dieter Arnold), and a spiraling ramp supported by the superstructure (Mark Lehner)

There is good information concerning the location of the quarries, tools used to cut stone, transportation of the stone to the monument, leveling the foundation, and leveling the subsequent tiers of the developing superstructure. Workmen used copper chisels, drills, and saws to cut softer stone, such as most of the limestone. The harder stones, such as granite, granodiorite, syenite, and basalt, could not be cut with copper tools alone; instead they were worked with time consuming methods like pounding with dolerite, drilling, and sawing with the aid of an abrasive, like quartzite sand. Blocks were transported by sledge lubricated by water. Leveling the foundation was accomplished by the use of water filled trenches. The unknowns of pyramid construction revolve around the question of how the blocks were moved up the superstructure. There is no known accurate historical or archaeological evidence that definitively resolves this question. Therefore, most discussion on construction methods involves functional possibilities that are supported by limited historical and archaeological evidence.

Historical accounts for the construction of the Egyptian pyramids do little to point directly to definitive methods to lift the blocks; yet most Egyptologists refer to these accounts when discussing this portion of pyramid construction. The first historical accounts of the construction of these monuments come centuries after the era of pyramid construction, by Herodotus in the 5th century BC and Diodorus Siculus in the 1st century BC. Herodotus^[4]' account states that ...

[6]

Diodorus Siculus' accounts states:

Both Herodotus and Diodorus Siculus' writings are known to contain gross errors of fact and Siculus is routinely accused of borrowing from Herodotus. Herodotus' description of slave labor is one of the most persistent myths of the construction process, and Diodorus Siculus' description of the shipment of the stone from Arabia is wildly incorrect. Since both accounts are known to be both false and true, it is impossible to select either technique from historical documents. However, these documents do give credit to both the levering and ramp methods.

Most Egyptologists acknowledge that ramps are the most tenable of the methods to raise the blocks, yet they acknowledge that it is an incomplete method which needs to be supplemented by another device. The method most accepted for assisting ramps is levering ^[5] (Lehner 1997: 222). The archaeological record gives evidence of only small ramps and inclined causeways, not something that could have been used to construct even a majority of the monument. To add to the uncertainty, there is considerable evidence demonstrating that non-standardized or ad hoc construction methods were used in pyramid construction (Arnold 1991: 98 ^[6], Lehner 1997: 223).

Therefore, there are many proposed ramps and there is a considerable amount of discrepancy regarding what type of ramp was used to build the pyramids.^[7] One of the widely discredited ramping methods is the large straight ramp, and it is routinely discredited on functional grounds for its massive size, lack of archaeological evidence, huge labor cost, and other problems (Arnold 1991: 99, Lehner 1997: 215, Isler 2001: 213^[8] However, the large straight ramp, seen in the picture above, is the only ramp design that can effectively build the entire monument. Other ramps serve to correct these problems of ramp size, yet either run into critiques of functionality, limited archaeological evidence, or the inability to construct the entire monument, mostly due to the limited space available at the top of the monument. There are zig-zagging ramps, Straight ramps utilizing the incomplete part of the superstructure (Arnold 1991), Spiraling ramps supported by the superstructure and spiraling ramps leaning on the monument as a large accretion, and spiraling ramps supported by the superstructure. Mark Lehner speculated that a spiraling ramp, beginning in the stone quarry to the southeast and continuing around the exterior of the pyramid, may have been used. The stone blocks may have been drawn on sleds along the ramps lubricated by water or milk.^[9] Yet each of these ramps are criticized for their inability to construct the entire monument. In other words, ramping methods work fine for most of the superstructure, but cannot create the top or the entire monument.

Levering methods are considered to be the most tenable solution to complement ramping methods, partially due to Herodotus' description; and partially to the Shadoof; an irrigation device first depicted in Egypt during the New Kingdom, and found concomitantly with the Old Kingdom in Mesopotamia. In Lehner's (1997: 222) point of view, levers should be employed to lift the top 3% of the material of the superstructure. It is important to note that the top 4% of this material comprises 1/3rd of the total height of the monument. In other words, in Lehner's view, levers should be employed to lift a small amount of material and a great deal of vertical height of the monument.

In the milieu of levering methods, there are those which lift the block incrementally, as in repeatedly prying up alternating sides of the block and inserting a wooden or stone shims to gradually move the stone up one course; and there are other methods that use a larger lever to move the block up one course in one lifting procedure. Since the discussion of construction techniques to lift the blocks attempts to resolve a gap in the archaeological and historical record with a plausible functional explanation, the following examples by Isler, Keable, and Hussey-Pailos ^[10] list experimentally tested methods. Isler's method (1985, 1987) is an incremental method and, in the Nova experiment (1992), used wooden shims or cribbing. Isler ^[11] was able to lift a block up one tier in approximately one hour and 30 minutes. Peter Hodges’ and Julian Keable’s^[12] method is similar to Isler's method and instead small manufactured concrete blocks as shims, wooden pallets, and a pit where their experimental tests were performed. Keable was able to perform his method in approximately 2 minutes. Scott Hussey-Pailos's (2005) method ^[10] uses a simple levering device to lift a block up course in one movement. This method was tested with materials of less strength than historical analogs (tested with materials weaker than those available in ancient Egypt), a factor of safety of 2, and lifted a 2500 pound block up one course in under a minute. This method is presented as a levering device to work complimentary with Mark Lehner's idea of a combined ramp and levering techniques.

Biblical researcher Ron Wyatt made the following claims of discovering a working levered machine in the late 1970s: "While reviewing ancient Egyptian inscriptions in an attempt to better understand the chronology of the "dynasties", I noticed that the glyph used to indicate the act of building was an abbreviated set of levers! I began sketching these levers and their mirror image. Suddenly, the whole process of pyramid building flashed into my mind! The simplicity of the machines and methods was astounding! Within minutes I had made a working model from strips cut from a cardboard box. With the aid of my children, brother and friends we soon made several working models of the machines.

In the fall of 1978, an international trade fair was held in Nashville, Tennessee. An Egyptian business friend that had charge of the Egyptian display asked my sons and I if we would set up a working demonstration of our pyramid building machines. The story was in the local news and on T.V. It also ran in an A.P. release.

Archaeologists, Egyptologists, ancient history buffs, and hundreds of other inquisitive people flocked to our demonstration. They came with towering and freely verbalized skepticism. After watching the demonstration, they stood agape, shook their heads and expressed dismay that such a simple solution to so long time a mystery had not been solved ages ago!

In the early spring of 1979 my children (Michelle, Daniel, and Ronny) and I took several working models of the old, II machines to Egypt. We are grateful to Royal Jordanian Airlines for their kindness in flying all those timbers to Egypt at no cost to us! We contacted Nassef Mohamed Hassan who was the director of Antiquities for Egypt and a man we had given diagrams showing the pyramid building process in the fall of 1978. He was delighted to give us permission to set the machines up on the middle pyramid at Giza (Chephren). We demonstrated the building technique on the actual pyramid, allowed a news crew from Nippon T.V. to film a brief clip, and filmed the process for our film library. Mr. Hassan and I were invited to explain the discovery and technique on a Voice of America radio broadcast!" (http://www.pilgrimpromo.com/WAR/noah/html/n06.htm)

Mr Hassan apparently told Ron at the time that numbers of levers had been found at various sites that had not been understood. They initially believed that they were parts of a dismantled boat, but they fitted exactly the bent levers in Ron's device. (Source: Video from WAR)

The following links have photos of the machine: http://www.pinkoski.com/content/view/21/36/, http://wyattmuseum.com/how-the-pyramids-were-built-02.htm.

It has also been suggested that Egyptians might have moved the stones with wind power, relying on kites and pulleys rather than huge numbers of slaves. On June 23, 2001, Caltech aeronautics professor Mory Gharib and a small team of undergraduates working in the California desert raised a 6900 lb (3.1 tonne), 3 metre tall obelisk into a vertical position in 22 mph (35 km/h) winds in under 25 seconds. They used only a kite, a pulley system, and a support frame to demonstrate that wind power can be harnessed to create large lifting forces. Maureen Clemmons first thought of this idea after seeing an image in Smithsonian of some men raising an obelisk. Clemmons also found a frieze that showed an unidentifiable wing pattern directly above some men and possible ropes.^[13]

[edit] Limestone concrete theory

Materials scientist Joseph Davidovits has posited that the blocks of the pyramid are not carved stone, but mostly a form of limestone concrete and that they were 'cast' as with modern cement^[14]. According to this theory, soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza Plateau. The limestone was then dissolved in large, Nile-fed pools until it became a watery slurry. Lime (found in the ash of cooking fires) and natron (also used by the Egyptians in mummification) was mixed in. The pools were then left to evaporate, leaving behind a moist, clay-like mixture. This wet "concrete" would be carried to the construction site where it would be packed into reusable wooden moulds and in a few days would undergo a chemical reaction similar to the 'setting' of cement. New blocks, he suggests, could be cast in place, on top of and pressed against the old blocks. Proof-of-concept tests using similar compounds were carried out at a geopolymer institute in northern France and it was found that a crew of ten, working with simple hand tools, could build a structure of fourteen, 1.3- to 4.5-ton blocks in a couple of days. ^[15] He claims he found hieroglyphic texts stating they used this technology.

Davidovits' method is not accepted by the academic mainstream. His method deals only with limestone, and not with granite stones weighing well over 10 tons, which he says were carved. Geologists have heavily scrutinized Davidovits results and concluded that his came from natural limestone quarried in the Mokattam Formation. ^[16] However, Davidovits alleges that the bulk of soft limestone is coming from the same natural Mokkatam Formation quarries found by geologists, and insists that ancient Egyptians used the soft marly layer instead of the hard one to re-agglomerate stones, which some geologists disagree.

[edit] References

1. ^ [1]
2. ^ [2] "Vitruvius's books of architecture"
3. ^ [3] David H. Koch Pyramids Radiocarbon Project
4. ^ [4]
5. ^ Lehner, Mark 1997. The Complete Pyramids. Thames and Hudson. New York.
6. ^ Arnold, Dieter. 1991. Building in Egypt: Pharonic Stone Masonry. Oxford University Press. New York, New York.
7. ^ Hawass, Zahi (2006). Building a Pyramid. Retrieved on March 17, 2007.
8. ^ Isler, Martin “On Pyramid Building II.” in Journal of the American Research Center in Egypt. XXII: 95-112. 2001. Sticks, Stones, and Shadows: Building the Egyptian Pyramids. University of Oklahoma Press, Norman).
9. ^ (2006) ThinkQuest. Cheops' Pyramid at Giza
10. ^ ^{a b} Hussey-Pailos, R. Scott 2005. Construction of the Top of the Egyptian Pyramids [electronic resource] : An Experimental Test of a Levering Device. Gainesville, Fla.] : University of Florida http://uf.aleph.fcla.edu/F/9VEY29LTF5JVSKSVX145H96UC2U63V75K64S84QGRMMG8UMFA9-01302?func=full-set-set&set_number=012575&set_entry=000001&format=999 or http://www.scott.hussey.com/R_Hussey.PDF
11. ^ Nova 1997. This Old Pyramid: Transcript. Electronic Document [5]
12. ^ Hodges, Peter. (Julian Keable ed.) 1989. How the Pyramids Were Built. Dotesios Printers Ltd. Trowbridge, Wiltshire.
13. ^ (July 6, 2001)(2006) National Geographic. Researchers Lift Obelisk with kite to test theory on ancient pyramids
14. ^ French language wikipedia article describing his theory
15. ^ Ari-Kat technology, Science Applied to Archeology.
16. ^ Harrell, James A. and Bret E. Penrod. 1993. "The Great Pyramid Debate -- Evidence from the Lauer Sample." Journal of Geological Education, vol. 41:358-363.

[edit] External links

• The Jean-Pierre Houdin's Theory in Real-Time 3D
• http://www.cheops-pyramide.ch/pyramid-building.html
• http://www.prevos.net/pyramid/construction.htm