Egyptian pyramid construction techniques
Encyclopedia
There have been many hypotheses about the Egyptian pyramid construction techniques. These techniques seem to have developed over time; later pyramids were not built the same way as earlier ones. Most of the construction hypotheses are based on the idea that huge stones were carved with copper chisels from stone quarries, and these blocks were then dragged and lifted into position. Disagreements chiefly concern the methods used to move
In addition to the many unresolved arguments about the construction techniques, there have been disagreements as to the kind of workforce used. The Greeks
, many years after the event, believed it must have been built by slave labor
. Archaeologists now believe that the Great Pyramid of Giza
(at least) was built by tens of thousands of skilled workers who camped near the pyramids and worked for a salary or as a form of tax payment (levy) until the construction was completed, pointing to worker's cemeteries discovered in 1990 by archaeologists Zahi Hawass
and Mark Lehner
. For the Middle Kingdom Pyramid of Amenemhat II
, there is evidence from the annal stone of the king that foreigners from Palestine were used.
(near modern Cairo
) was used as the outer casing. Granite, quarried near Aswan
, was used to construct some architectural elements, including the portcullis
(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
seems to indicate acceptance of a newer technique at a transition between these two building techniques. Its lower section is built of sloping courses, while in its upper section the stones are laid horizontally.
, pyramid construction techniques changed again. Most pyramids built then 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 for the pyramid monuments of later pharaohs.
in De architectura
described a similar method for moving irregular weights. It is still not known whether the Egyptians used this method but the experiments indicate it could have worked using stones of this size. Egyptologists generally accept this for the 2.5 ton blocks mostly used but do not agree over the methods used for the 15+ ton and several 70 to 80 ton blocks.
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 which requires large quantities of wood. According to Egyptologists, the findings of both the 1984 and 1995 David H. Koch Pyramids Radiocarbon Projects may suggest that Egypt had to strip its forest and scrap every bit of wood it had to build the pyramids of Giza and other even earlier 4th Dynasty pyramids. Carbon dating samples from core blocks and other materials revealed that dates from the 1984 study averaged 374 years earlier than currently accepted and the 1995 dating averaging 100–200 years. As suggested by team members, "We thought that it was unlikely that the pyramid builders consistently used centuries-old wood as fuel in preparing mortar. The 1984 results left us with too little data to conclude that the historical chronology of the Old Kingdom was wrong by nearly 400 years, but we considered this at least a possibility". To explain this discrepancy, Egyptologists proposed the "old wood" theory claiming the earlier dates were possibly derived from recycling large amounts of centuries old wood and other earlier materials.
There is good information concerning the location of the quarries, some of the tools used to cut stone in the quarries (save that no copper chisels have yet been found there), transportation of the stone to the monument, leveling the foundation, and leveling the subsequent tiers of the developing superstructure. Workmen probably 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, cannot 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, such as quartz sand. Blocks were transported by sledge likely lubricated by water. Leveling the foundation may have been accomplished by use of water-filled trenches as suggested by Mark Lehner and I.E.S. Edwards or through the use of a crude square level and experienced surveyors.
Historical accounts for the construction of the Egyptian pyramids do little to point definitively to methods to lift the blocks; yet most Egyptologists refer to these accounts when discussing this portion of pyramid construction. Thales
, according to Hieronymus visited the Egyptian pyramids during the 7th century BC
and by using similar triangles, right triangle
s, and the shadow of the pyramids, measured their height and thus their volume. The first historical accounts of the construction of these monuments came centuries after the era of pyramid construction, by Herodotus
in the 5th century BC and Diodorus Siculus
in the 1st century BC. Herodotus' account states:
Diodorus Siculus' account 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 incorrect. Since both accounts are known to be unreliable, it is impossible to select either technique from historical documents as correct. 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 that must be supplemented by another device. Archaeological evidence for the use of ramps has been found at the Great Pyramid of Giza
and other pyramids. The method most accepted for assisting ramps is levering (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, 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. 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). 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 are proposed. 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. Yet each of these ramps is criticized for its 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.
Lever
ing 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 1/3 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 that 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 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 was able to lift a block up one tier in approximately one hour and 30 minutes. Peter Hodges’ and Julian Keable’s 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 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 complementary with Mark Lehner's idea of a combined ramp and levering techniques.
After 4 years working alone, Houdin was joined by a team of engineers from the French 3D software company Dassault Systemes
, who used the most modern computer-aided design
technology available to further refine and test the hypothesis, making it (according to Houdin) the only one proven to be a viable technique. In 2006 Houdin announced it in a book: Khufu: The Secrets Behind the Building of the Great Pyramid, and in 2008 he and Egyptologist Bob Brier
wrote a second one: The Secret of the Great Pyramid
In Houdin's method, each ramp inside the pyramid ended at an open space, a notch temporarily left open in the edge of the construction.(see diagram) This 10m square clear space housed a crane that lifted and rotated each 2.5 ton block, to ready it for eight men to drag up the next internal ramp. There is a notch of sorts in one of the right places, and in 2008 Houdin's co-author Bob Brier, with a National Geographic film crew, entered a previously unremarked chamber that could be the start of one of these internal ramps. In 1986 a member of the French team (see below) saw a desert fox at this notch, rather as if it had ascended internally.
Houdin's thesis remains unproven and as late as 2007, UCL Egyptologist Prof David Jeffreys described the internal spiral hypothesis as "far-fetched and horribly complicated", while Oxford University's Prof John Baines
, declared he was "suspicious of any theory that seeks to explain only how the Great Pyramid was built". However, one piece of evidence for it has surfaced. In 1986 a French survey team did a micro-gravimetric analysis of the structure. Not included in their final report, but clearly visible in some unpublished plottings, is a spiral feature in the right place. Houdin believes his theory will soon be proved or disproved by one of a number of well-understood techniques, even infrared photography of the pyramid cooling in the evening.
Houdin has another hypothesis developed from his architectural model, one that could finally explain the internal "Grand Gallery" chamber that otherwise appears to have little purpose. He believes the gallery acted as a trolley chute/guide for counter-balance weights. It enabled the raising of the five 60 ton granite beams that roof the King's Chamber. Some observers claim to be able to see wear-marks in the right places, and Houdin postulates that other puzzling features are actually fixings for wear-strips. Houdin and Brier and the Dassault team are already credited with proving for the first time that cracks in beams appeared during construction, were examined and tested at the time and declared relatively harmless.
Joseph Davidovits
has claimed 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 concrete. According to this hypothesis, 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 concrete. 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 five to ten, working with simple hand tools, could agglomerate a structure of five, 1.3- to 4.5-ton blocks in a couple of weeks. He also claims that the Famine Stele, along with other hieroglyphic texts, describe the technology of stone agglomeration.
Davidovits' method is not accepted by the academic mainstream. His method does not explain the granite stones, weighing well over 10 tons, above the "King's Chamber", which he agrees were carved. Geologists have carefully scrutinized Davidovits' suggested technique and concluded his came from natural limestone quarried in the Mokattam Formation. However, Davidovits alleges that the bulk of soft limestone came 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.
Davidovits' hypothesis recently gained support from Michel Barsoum, a materials science researcher. Michel Barsoum and his colleagues at Drexel University
published their findings supporting Davidovits' hypothesis in the Journal of the American Ceramic Society in 2006. Utilizing scanning electron microscopy
, they discovered mineral compounds and air bubbles in samples of the limestone pyramid blocks that do not occur in natural limestone.
Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 and gave a paper in which he discusses Davidovits' and Barsoum's work and concludes "we are far from accepting even as a remote possibility of a “manmade” origin of pyramid stones."
and Roger Hopkins, a stonemason from Sudbury, Massachusetts
, teamed up to conduct a pyramid building experiment for a NOVA
television episode. They built a pyramid 6 metres (19.7 ft) high by 9 metres (29.5 ft) wide. A total of 162 cubic metre, or about 405 tons. It was made out of 186 stones weighing a average of 2.2 ton
s each. They had a total of just over 3 weeks to build it due to their filming schedule. 12 quarrymen carved 186 stones in 22 days. They were able to erect it using 44 men. They used iron
hammers, chisels and levers (this is a modern short-cut, the ancient Egyptians were limited to using copper
and wood
). But they did experiments with copper tools, noting that they were adequate for the job in hand, only provided that additional manpower was available to constantly re-sharpen the ancient tools. They estimated they would have needed around 20 extra men for this maintenance. Another short-cut taken was the use of a front end loader
or fork lift truck. However, modern machinery was not and could not be used to finish the construction. They used levers to lift the capstone to a height of 20 feet (6.1 m). Four or five men were able to use levers on stones less than 1 ton to flip them over and transport them by rolling them. For the larger stones they had to tow them. They found that by putting the stones on wooden sledges and sliding the sledges on wooden tracks they were able to tow a 2 ton stone with 12 to 20 men. The wood for these sledges and tracks would have to have been imported from Lebanon
at great cost since there was little, if any, wood in ancient Egypt. While the builders failed to duplicate the precise jointing created by the ancient Egyptians, Hopkins was confident this could have been achieved with more practice.
Kurt Mendelssohn
calculated that the workforce may have been 50,000 men at most, while Ludwig Borchardt
and Louis Croon placed the number at 36,000. According to Miroslav Verner
, a workforce of no more than 30,000 was needed in the Great Pyramid's construction.
A construction management study (testing) carried out by the firm Daniel, Mann, Johnson, & Mendenhall in association with Mark Lehner
and other Egyptologists, estimates that the total project required an average workforce of 14,567 people and a peak workforce of 40,000. Without the use of pulleys, wheels, or iron tools, they used critical path analysis to suggest the Great Pyramid was completed from start to finish in approximately 10 years. Their study estimates that the number of blocks used in construction was between 2 and 2.8 million (an average of 2.4 million), but settles on a reduced finished total of 2 million after subtracting the estimated volume of the hollow spaces of the chambers and galleries. Most sources agree on this number of blocks somewhere above 2.3 million. Their calculations suggest the workforce could have sustained a rate of 180 blocks per hour (3 blocks/minute) with ten hour work days for putting each individual block in place. They derived these estimates from modern third-world construction projects that did not use modern machinery, but conclude it is still unknown exactly how the Great Pyramid was built. As Dr. Craig Smith of the team points out:
The entire Giza Plateau
is believed to have been constructed over the reign of five pharaohs in less than a hundred years, which generally includes: the Great Pyramid, Khafre and Menkuare's pyramids, the Great Sphinx, the Sphinx and Valley Temples, 35 boat pits cut out of solid bedrock, and several causeways, as well as paving nearly the entire plateau with large stones. This does not include Khafre's son Djedefre's northern pyramid, Abu Rawash, which would have also been built during this time frame of 100 years. In the hundred years prior to Giza, beginning with Djoser
who ruled from 2687–2667 BC, amongst dozens of other temples, smaller pyramids and general construction projects, three other massive pyramids were built – the Step pyramid
of Saqqara (believed to be the first Egyptian pyramid), the Bent Pyramid
, and the Red Pyramid
. Also during this period (between 2686 and 2498 BC) the Wadi Al-Garawi dam, which used an estimated 100,000 cubic meters of rock and rubble, was built.
In addition to the many unresolved arguments about the construction techniques, there have been disagreements as to the kind of workforce used. The Greeks
Greeks
The Greeks, also known as the Hellenes , are a nation and ethnic group native to Greece, Cyprus and neighboring regions. They also form a significant diaspora, with Greek communities established around the world....
, many years after the event, believed it must have been built by slave labor
Slavery
Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...
. Archaeologists now believe that the Great Pyramid of Giza
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...
(at least) was built by tens of thousands of skilled workers who camped near the pyramids and worked for a salary or as a form of tax payment (levy) until the construction was completed, pointing to worker's cemeteries discovered in 1990 by archaeologists Zahi Hawass
Zahi Hawass
Zahi Hawass is an Egyptian archaeologist, an Egyptologist, and former Minister of State for Antiquities Affairs. He has also worked at archaeological sites in the Nile Delta, the Western Desert, and the Upper Nile Valley....
and Mark Lehner
Mark Lehner
Mark Lehner PhD is an American archaeologist with more than 30 years of experience excavating in Egypt. His approach, as director of Ancient Egypt Research Associates , is to conduct interdisciplinary archaeological investigation. Every excavated object is examined by specialists to create an...
. For the Middle Kingdom Pyramid of Amenemhat II
Amenemhat II
Nubkhaure Amenemhat II was the third pharaoh of the Twelfth Dynasty of Ancient Egypt. Not much is known about his reign. He ruled Egypt for 35 years from 1929 BC to 1895 BC and was the son of Senusret I through the latter's chief wife, Queen Nefru. His queen is not known; although recently a...
, there is evidence from the annal stone of the king that foreigners from Palestine were used.
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 TuraTura (Egypt)
Tura was a site in Ancient Egypt, located about halfway between modern Cairo and Helwan. It was Egypt's primary quarry for limestone. The limestone from Tura was the finest and whitest of all the Egyptian quarries, so it was used for facing stones for the richest tombs, as well as for the floors...
(near modern Cairo
Cairo
Cairo , is the capital of Egypt and the largest city in the Arab world and Africa, and the 16th largest metropolitan area in the world. Nicknamed "The City of a Thousand Minarets" for its preponderance of Islamic architecture, Cairo has long been a centre of the region's political and cultural life...
) was used as the outer casing. Granite, quarried near Aswan
Aswan
Aswan , formerly spelled Assuan, is a city in the south of Egypt, the capital of the Aswan Governorate.It stands on the east bank of the Nile at the first cataract and is a busy market and tourist centre...
, was used to construct some architectural elements, including the portcullis
Portcullis
A portcullis is a latticed grille made of wood, metal, fibreglass or a combination of the three. Portcullises fortified the entrances to many medieval castles, acting as a last line of defence during time of attack or siege...
(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
Bent Pyramid
The Bent Pyramid is an ancient Egyptian pyramid located at the royal necropolis of Dahshur, approximately 40 kilometres south of Cairo, built under the Old Kingdom Pharaoh Sneferu...
at Dahshur
Dahshur
Dahshur , is a royal necropolis located in the desert on the west bank of the Nile approximately 40 kilometres south of Cairo...
seems to indicate acceptance of a newer technique at a transition between these two building techniques. Its lower section is built of sloping courses, while in its upper section the stones are laid horizontally.
Middle Kingdom and onward
During the Middle KingdomMiddle Kingdom of Egypt
The Middle Kingdom of Egypt is the period in the history of ancient Egypt stretching from the establishment of the Eleventh Dynasty to the end of the Fourteenth Dynasty, between 2055 BC and 1650 BC, although some writers include the Thirteenth and Fourteenth dynasties in the Second Intermediate...
, pyramid construction techniques changed again. Most pyramids built then 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 for the pyramid monuments of later pharaohs.
Building the pyramids from quarried stones
One of the major problems faced by the early pyramid builders was the need to move huge quantities of rock. The Twelfth Dynasty tomb of Djehutihotep has an illustration of 172 men pulling an alabaster statue of him on a sledge. The statue is estimated to weigh 60 tons and Denys Stocks estimated that 45 workers would be required to start moving a 16,300 kg lubricated block, or eight workers to move a 2,750 kg block. Dr R H G Parry 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. VitruviusVitruvius
Marcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....
in De architectura
De architectura
' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...
described a similar method for moving irregular weights. It is still not known whether the Egyptians used this method but the experiments indicate it could have worked using stones of this size. Egyptologists generally accept this for the 2.5 ton blocks mostly used but do not agree over the methods used for the 15+ ton and several 70 to 80 ton blocks.
As the stones forming the core of the pyramids were roughly cut, especially in the Great Pyramid
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...
, 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 which requires large quantities of wood. According to Egyptologists, the findings of both the 1984 and 1995 David H. Koch Pyramids Radiocarbon Projects may suggest that Egypt had to strip its forest and scrap every bit of wood it had to build the pyramids of Giza and other even earlier 4th Dynasty pyramids. Carbon dating samples from core blocks and other materials revealed that dates from the 1984 study averaged 374 years earlier than currently accepted and the 1995 dating averaging 100–200 years. As suggested by team members, "We thought that it was unlikely that the pyramid builders consistently used centuries-old wood as fuel in preparing mortar. The 1984 results left us with too little data to conclude that the historical chronology of the Old Kingdom was wrong by nearly 400 years, but we considered this at least a possibility". To explain this discrepancy, Egyptologists proposed the "old wood" theory claiming the earlier dates were possibly derived from recycling large amounts of centuries old wood and other earlier materials.
There is good information concerning the location of the quarries, some of the tools used to cut stone in the quarries (save that no copper chisels have yet been found there), transportation of the stone to the monument, leveling the foundation, and leveling the subsequent tiers of the developing superstructure. Workmen probably 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, cannot 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, such as quartz sand. Blocks were transported by sledge likely lubricated by water. Leveling the foundation may have been accomplished by use of water-filled trenches as suggested by Mark Lehner and I.E.S. Edwards or through the use of a crude square level and experienced surveyors.
The writings of Herodotus and Diodorus Siculus
The unknowns of pyramid construction chiefly center on the question of how the blocks were moved up the superstructure. There is no known accurate historical or archaeological evidence that definitively resolves the 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 definitively to methods to lift the blocks; yet most Egyptologists refer to these accounts when discussing this portion of pyramid construction. Thales
Thales
Thales of Miletus was a pre-Socratic Greek philosopher from Miletus in Asia Minor, and one of the Seven Sages of Greece. Many, most notably Aristotle, regard him as the first philosopher in the Greek tradition...
, according to Hieronymus visited the Egyptian pyramids during the 7th century BC
7th century BC
The 7th century BC started the first day of 700 BC and ended the last day of 601 BC.The Assyrian Empire continued to dominate the Near East during this century, exercising formidable power over neighbors like Babylon and Egypt. In the last two decades of the century, however, the empire began to...
and by using similar triangles, right triangle
Right triangle
A right triangle or right-angled triangle is a triangle in which one angle is a right angle . The relation between the sides and angles of a right triangle is the basis for trigonometry.-Terminology:The side opposite the right angle is called the hypotenuse...
s, and the shadow of the pyramids, measured their height and thus their volume. The first historical accounts of the construction of these monuments came centuries after the era of pyramid construction, by Herodotus
Herodotus
Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...
in the 5th century BC and Diodorus Siculus
Diodorus Siculus
Diodorus Siculus was a Greek historian who flourished between 60 and 30 BC. According to Diodorus' own work, he was born at Agyrium in Sicily . With one exception, antiquity affords no further information about Diodorus' life and doings beyond what is to be found in his own work, Bibliotheca...
in the 1st century BC. Herodotus' account states:
Diodorus Siculus' account 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 incorrect. Since both accounts are known to be unreliable, it is impossible to select either technique from historical documents as correct. However, these documents do give credit to both the levering and ramp methods.
Various kinds of ramps
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...
and other pyramids. The method most accepted for assisting ramps is levering (Lehner 1997: 222). The archaeological record
Archaeological record
The archaeological record is the body of physical evidence about the past. It is one of the most basic concepts in archaeology, the academic discipline concerned with documenting and interpreting 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
Ad hoc
Ad hoc is a Latin phrase meaning "for this". It generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes. Compare A priori....
construction methods were used in pyramid construction (Arnold 1991: 98, 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. 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). 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 are proposed. Mark Lehner
Mark Lehner
Mark Lehner PhD is an American archaeologist with more than 30 years of experience excavating in Egypt. His approach, as director of Ancient Egypt Research Associates , is to conduct interdisciplinary archaeological investigation. Every excavated object is examined by specialists to create an...
speculated that a spiraling ramp, beginning in the stone quarry
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
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. Yet each of these ramps is criticized for its 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.
Lever
Lever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...
ing methods are considered to be the most tenable solution to complement ramping methods, partially due to Herodotus' description; and partially to the Shadoof
Shadoof
A shadoof, shaduf, dhenkli, picottah or counterpoise-lift is an irrigation tool...
; 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 1/3 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 that 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 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 was able to lift a block up one tier in approximately one hour and 30 minutes. Peter Hodges’ and Julian Keable’s 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 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 complementary with Mark Lehner's idea of a combined ramp and levering techniques.
Jean-Pierre Houdin's "internal ramp" hypothesis
Houdin's father was an architect who, in 1999, thought up a construction method that, it seemed to him, made more sense than any existing method proposed for the building of pyramids. To develop this hypothesis, Jean-Pierre Houdin, also an architect, gave up his job and set about drawing the first fully functional CAD architectural model of the Great Pyramid. His/their scheme involves the use of a regular external ramp to build the first 30% of the pyramid, with an "internal ramp" taking stones up beyond that height. The stones of the external ramp are re-cycled into the upper stories, thus explaining the otherwise puzzling lack of evidence for ramps.After 4 years working alone, Houdin was joined by a team of engineers from the French 3D software company Dassault Systemes
Dassault Systemes
Dassault Systèmes S.A. is a leading company specializing in 3D and PLM software.Dassault Systèmes develops and markets PLM application software and services that support industrial processes and provide a 3D vision of the entire lifecycle of products from conception to maintenance to recycling...
, who used the most modern computer-aided design
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...
technology available to further refine and test the hypothesis, making it (according to Houdin) the only one proven to be a viable technique. In 2006 Houdin announced it in a book: Khufu: The Secrets Behind the Building of the Great Pyramid, and in 2008 he and Egyptologist Bob Brier
Bob Brier
Robert Brier , also known as Mr. Mummy, is an American Egyptologist specializing in paleopathology. A Senior Research Fellow at the C.W...
wrote a second one: The Secret of the Great Pyramid
In Houdin's method, each ramp inside the pyramid ended at an open space, a notch temporarily left open in the edge of the construction.(see diagram) This 10m square clear space housed a crane that lifted and rotated each 2.5 ton block, to ready it for eight men to drag up the next internal ramp. There is a notch of sorts in one of the right places, and in 2008 Houdin's co-author Bob Brier, with a National Geographic film crew, entered a previously unremarked chamber that could be the start of one of these internal ramps. In 1986 a member of the French team (see below) saw a desert fox at this notch, rather as if it had ascended internally.
Houdin's thesis remains unproven and as late as 2007, UCL Egyptologist Prof David Jeffreys described the internal spiral hypothesis as "far-fetched and horribly complicated", while Oxford University's Prof John Baines
John Baines
John Baines is the incumbent Professor of Egyptology at the University of Oxford and a fellow of The Queen's College. He is the author of multiple scholarly articles and publications relating to ancient Egyptian civilization....
, declared he was "suspicious of any theory that seeks to explain only how the Great Pyramid was built". However, one piece of evidence for it has surfaced. In 1986 a French survey team did a micro-gravimetric analysis of the structure. Not included in their final report, but clearly visible in some unpublished plottings, is a spiral feature in the right place. Houdin believes his theory will soon be proved or disproved by one of a number of well-understood techniques, even infrared photography of the pyramid cooling in the evening.
Houdin has another hypothesis developed from his architectural model, one that could finally explain the internal "Grand Gallery" chamber that otherwise appears to have little purpose. He believes the gallery acted as a trolley chute/guide for counter-balance weights. It enabled the raising of the five 60 ton granite beams that roof the King's Chamber. Some observers claim to be able to see wear-marks in the right places, and Houdin postulates that other puzzling features are actually fixings for wear-strips. Houdin and Brier and the Dassault team are already credited with proving for the first time that cracks in beams appeared during construction, were examined and tested at the time and declared relatively harmless.
Limestone concrete hypothesis
Materials scientistMaterials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...
Joseph Davidovits
Joseph Davidovits
Joseph Davidovits is a French materials scientist who has posited that the blocks of the Great Pyramid are not carved stone but mostly a form of limestone concrete...
has claimed that the blocks of the pyramid are not carved stone, but mostly a form of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
and that they were "cast" as with modern concrete. According to this hypothesis, soft limestone with a high kaolinite
Kaolinite
Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O54. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra...
content was quarried in the wadi
Wadi
Wadi is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry riverbed that contains water only during times of heavy rain or simply an intermittent stream.-Variant names:...
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
Natron
Natron is a naturally occurring mixture of sodium carbonate decahydrate and about 17% sodium bicarbonate along with small quantities of household salt and sodium sulfate. Natron is white to colourless when pure, varying to gray or yellow with impurities...
(also used by the Egyptians in mummification
Mummy
A mummy is a body, human or animal, whose skin and organs have been preserved by either intentional or incidental exposure to chemicals, extreme coldness , very low humidity, or lack of air when bodies are submerged in bogs, so that the recovered body will not decay further if kept in cool and dry...
) 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 concrete. 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 five to ten, working with simple hand tools, could agglomerate a structure of five, 1.3- to 4.5-ton blocks in a couple of weeks. He also claims that the Famine Stele, along with other hieroglyphic texts, describe the technology of stone agglomeration.
Davidovits' method is not accepted by the academic mainstream. His method does not explain the granite stones, weighing well over 10 tons, above the "King's Chamber", which he agrees were carved. Geologists have carefully scrutinized Davidovits' suggested technique and concluded his came from natural limestone quarried in the Mokattam Formation. However, Davidovits alleges that the bulk of soft limestone came 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.
Davidovits' hypothesis recently gained support from Michel Barsoum, a materials science researcher. Michel Barsoum and his colleagues at Drexel University
Drexel University
Drexel University is a private research university with the main campus located in Philadelphia, Pennsylvania, USA. It was founded in 1891 by Anthony J. Drexel, a noted financier and philanthropist. Drexel offers 70 full-time undergraduate programs and accelerated degrees...
published their findings supporting Davidovits' hypothesis in the Journal of the American Ceramic Society in 2006. Utilizing scanning electron microscopy
Scanning electron microscope
A scanning electron microscope is a type of electron microscope that images a sample by scanning it with a high-energy beam of electrons in a raster scan pattern...
, they discovered mineral compounds and air bubbles in samples of the limestone pyramid blocks that do not occur in natural limestone.
Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 and gave a paper in which he discusses Davidovits' and Barsoum's work and concludes "we are far from accepting even as a remote possibility of a “manmade” origin of pyramid stones."
NOVA pyramid building experiment
In 1997 Mark LehnerMark Lehner
Mark Lehner PhD is an American archaeologist with more than 30 years of experience excavating in Egypt. His approach, as director of Ancient Egypt Research Associates , is to conduct interdisciplinary archaeological investigation. Every excavated object is examined by specialists to create an...
and Roger Hopkins, a stonemason from Sudbury, Massachusetts
Sudbury, Massachusetts
Sudbury is a town in Middlesex County, Massachusetts, United States, population 17,659. The town was incorporated in 1639, with the original boundaries including what is now Wayland. Wayland split from Sudbury in 1780. When first incorporated, it included and parts of Framingham, Marlborough, Stow...
, teamed up to conduct a pyramid building experiment for a NOVA
NOVA (TV series)
Nova is a popular science television series from the U.S. produced by WGBH Boston. It can be seen on the Public Broadcasting Service in the United States, and in more than 100 other countries...
television episode. They built a pyramid 6 metres (19.7 ft) high by 9 metres (29.5 ft) wide. A total of 162 cubic metre, or about 405 tons. It was made out of 186 stones weighing a average of 2.2 ton
Ton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s each. They had a total of just over 3 weeks to build it due to their filming schedule. 12 quarrymen carved 186 stones in 22 days. They were able to erect it using 44 men. They used iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
hammers, chisels and levers (this is a modern short-cut, the ancient Egyptians were limited to using copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
and wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
). But they did experiments with copper tools, noting that they were adequate for the job in hand, only provided that additional manpower was available to constantly re-sharpen the ancient tools. They estimated they would have needed around 20 extra men for this maintenance. Another short-cut taken was the use of a front end loader
Front End Loader
Front End Loader is an Australian rock band consisting of Davis Claymore , Bowden Campbell , Richard Corey , and Peter Kostic . Peter also drums for Regurgitator and The Hard-Ons.-History:...
or fork lift truck. However, modern machinery was not and could not be used to finish the construction. They used levers to lift the capstone to a height of 20 feet (6.1 m). Four or five men were able to use levers on stones less than 1 ton to flip them over and transport them by rolling them. For the larger stones they had to tow them. They found that by putting the stones on wooden sledges and sliding the sledges on wooden tracks they were able to tow a 2 ton stone with 12 to 20 men. The wood for these sledges and tracks would have to have been imported from Lebanon
Lebanon
Lebanon , officially the Republic of LebanonRepublic of Lebanon is the most common term used by Lebanese government agencies. The term Lebanese Republic, a literal translation of the official Arabic and French names that is not used in today's world. Arabic is the most common language spoken among...
at great cost since there was little, if any, wood in ancient Egypt. While the builders failed to duplicate the precise jointing created by the ancient Egyptians, Hopkins was confident this could have been achieved with more practice.
Great Pyramid
Some research suggests alternate estimates to the accepted workforce size. For instance, mathematicianMathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
Kurt Mendelssohn
Kurt Mendelssohn
Kurt Alfred Georg Mendelssohn FRS was a German-born British medical physicist, elected a Fellow of the Royal Society 1951.He was a great-great-grandson of Saul Mendelssohn, the younger brother of philosopher Moses Mendelssohn...
calculated that the workforce may have been 50,000 men at most, while Ludwig Borchardt
Ludwig Borchardt
Ludwig Borchardt was a German Egyptologist who was born in Berlin.-Life:Borchardt initially studied Architecture and later Egyptology under Adolf Erman. In 1895 he journeyed to Cairo and produced, with Gaston Maspero, the Catalogue of the Egyptian Museum...
and Louis Croon placed the number at 36,000. According to Miroslav Verner
Miroslav Verner
Prof. Dr. Miroslav Verner, DrSc. is a Czech Egyptologist, who specializes in the history and archaeology of Ancient Egypt of the Old Kingdom....
, a workforce of no more than 30,000 was needed in the Great Pyramid's construction.
A construction management study (testing) carried out by the firm Daniel, Mann, Johnson, & Mendenhall in association with Mark Lehner
Mark Lehner
Mark Lehner PhD is an American archaeologist with more than 30 years of experience excavating in Egypt. His approach, as director of Ancient Egypt Research Associates , is to conduct interdisciplinary archaeological investigation. Every excavated object is examined by specialists to create an...
and other Egyptologists, estimates that the total project required an average workforce of 14,567 people and a peak workforce of 40,000. Without the use of pulleys, wheels, or iron tools, they used critical path analysis to suggest the Great Pyramid was completed from start to finish in approximately 10 years. Their study estimates that the number of blocks used in construction was between 2 and 2.8 million (an average of 2.4 million), but settles on a reduced finished total of 2 million after subtracting the estimated volume of the hollow spaces of the chambers and galleries. Most sources agree on this number of blocks somewhere above 2.3 million. Their calculations suggest the workforce could have sustained a rate of 180 blocks per hour (3 blocks/minute) with ten hour work days for putting each individual block in place. They derived these estimates from modern third-world construction projects that did not use modern machinery, but conclude it is still unknown exactly how the Great Pyramid was built. As Dr. Craig Smith of the team points out:
The entire Giza Plateau
Giza Plateau
The Giza Plateau is a plateau that is located in Giza, Egypt. The famous Giza Necropolis is located in this geographical area, which is characterized by a sandy, desert climate and terrain with little vegetation....
is believed to have been constructed over the reign of five pharaohs in less than a hundred years, which generally includes: the Great Pyramid, Khafre and Menkuare's pyramids, the Great Sphinx, the Sphinx and Valley Temples, 35 boat pits cut out of solid bedrock, and several causeways, as well as paving nearly the entire plateau with large stones. This does not include Khafre's son Djedefre's northern pyramid, Abu Rawash, which would have also been built during this time frame of 100 years. In the hundred years prior to Giza, beginning with Djoser
Djoser
Netjerikhet or Djoser is the best-known pharaoh of the Third dynasty of Egypt. He commissioned his official, Imhotep, to build the first of the pyramids, a step pyramid for him at Saqqara...
who ruled from 2687–2667 BC, amongst dozens of other temples, smaller pyramids and general construction projects, three other massive pyramids were built – the Step pyramid
Step pyramid
Step pyramids are structures which characterized several cultures throughout history, in several locations throughout the world. These pyramids typically are large and made of several layers of stone...
of Saqqara (believed to be the first Egyptian pyramid), the Bent Pyramid
Bent Pyramid
The Bent Pyramid is an ancient Egyptian pyramid located at the royal necropolis of Dahshur, approximately 40 kilometres south of Cairo, built under the Old Kingdom Pharaoh Sneferu...
, and the Red Pyramid
Red Pyramid
The Red Pyramid, also called the North Pyramid, is the largest of the three major pyramids located at the Dahshur necropolis. Named for the rusty reddish hue of its stones, it is also the third largest Egyptian pyramid, after those of Khufu and Khafra at Giza. At the time of its completion, it was...
. Also during this period (between 2686 and 2498 BC) the Wadi Al-Garawi dam, which used an estimated 100,000 cubic meters of rock and rubble, was built.
External links
- How to Build a Pyramid, Archaeology Magazine, May/June 2007
- Engineering the Pyramids - Materials Science and Engineering @ Drexel University
- Rope pull hypothesis - alternative hypothesis by Heribert Illig and Franz Löhner
- Collection of alternative construction essays
- Did the Great Pyramid Have an Elevator? The Structural Engineer, April 2009
- The main problems / drawbacks of all ramp systems
- 3D Unveils Great Pyramid's Mystery - illustrates hypothesis of Houdin and Brier.