Pyramids of Giza: Engineering Techniques and Theories Behind Their Construction

It's truly amazing that the ancient Egyptians could construct the Pyramids of Giza without the aid of modern machinery or even the wheel. Although they relied solely on human ingenuity and sheer manpower, these Egyptians created monuments that have lasted more than 4,500 years. In fact, the Great Pyramid is the only remaining structure out of the Seven Wonders of the Ancient World.

The three Pyramids of Giza are located on the Giza Plateau, about 13 km (8 miles) west of Cairo and 5 km (3 miles) from the west bank of the Nile River. The pyramids were built between 2600 BCE and 2500 BCE during the Fourth Dynasty of the Old Kingdom of Egypt. They served as huge tombs that protected the pharaohs during their afterlife.

True to their name, the pyramids have a pyramidal structure, meaning they have a square base and four triangular sides. They are made of heavy stone blocks with limited use of mortar created from gypsum (calcium sulfate) and water. The construction of the pyramids must have required extensive planning and engineering skills since the ancient Egyptians lacked modern machinery.

Each pyramid took about 20 years and around 20,000 to 30,000 workers to build. The Great Pyramid of Khufu was the largest and first to be built. It is estimated that the Great Pyramid was originally 146.7 meters (481 feet) tall, with each side of its base measuring 230.4 meters (756 feet) in length. Building a pyramid this large required over 2 million stones weighing 2.5 to 15 tons on average. The Pyramid of Khafre was built next. It appears taller than the Great Pyramid because it sits higher on the plateau. However, it is smaller, with an original height of about 143.5 meters (471 feet). The smallest and last one to be built is The Pyramid of Menkaure. Its original height was about 65.5 meters (215 feet). All three pyramids are now smaller due to the loss of their capstones and outer casings from theft and erosion.

I visited the Great Pyramid of Khufu in 2021. I walked across the wide stone base and climbed up the giant blocks on the outside. The entrance sat partway up the side of the pyramid, and I had to step carefully to reach it.

Once inside the Great Pyramid, I climbed through a narrow passage and walked up steep ramps. The air felt hot and heavy, and the walls were smooth stone. I followed the ramp up to the Grand Gallery, then entered the King's Chamber. The room was dark and quiet, with high ceilings and a stone box at the center. It felt amazing to stand inside one of the oldest structures in the world.

The core structures of the pyramids were built using yellow limestone from local quarries, and their outer casings were made of finer quality white limestone from the nearby town of Tura. However, the granite used in their inner chambers was quarried from Aswan, which is over 800 kilometers away. It is not known for certain how the massive stones were moved from the quarries to the pyramid construction sites, but several theories have been proposed. Some researchers believe that the Egyptians loaded the stones onto large flat-bottomed boats and then shipped them to the construction site via the Nile River. In addition, the Egyptians may have dug canals that would allow the boats to take the stones very close to the pyramid's base. Interestingly, the Egyptians may have used their knowledge of the annual flooding and subsequent receding of the Nile River to load and unload the stones. During the flood season, the boats could float close to loading points at the quarries. Once loaded, the boats could make the most of the high-water levels to navigate the canals near the construction site. As the floodwaters receded, the boats would gradually be lowered in the water, which would make unloading the heavy stones easier.

Once the stones were unloaded, they needed to be moved overland to the construction site. Evidence suggests that the Egyptians used wooden sleds to haul the heavy blocks over the sand. In addition, the tracks over which these sleds moved were lubricated with water to reduce friction with the sand, making it much easier to drag the heavy stones. This process is depicted in wall paintings found in the tomb of Djehutihotep. These paintings show large statues being moved on sleds, with workers pulling and others pouring liquid (likely water) in front of the sled.

A-wall-painting-from-1880-BC-on-the-tomb-of-Djehutihotep-9-A-sledge-with-a-big.png

Wall painting from the tomb of Djehutihotep (c. 1880 BCE), showing workers transporting a statue on a sled. Reproduced from the Griffith Institute, University of Oxford.

It is also not known how the massive stones were lifted and positioned as the pyramids were being built. Several theories suggest that ramps played a role. The straight ramp theory proposes that a straight ramp was built from the ground up to the construction level. However, the immense size and length required for such a ramp to reach the top of a pyramid make this theory questionable. As an alternative, the zigzag ramp theory proposes that a ramp zigzagged up one side of the pyramid. A zigzag ramp would allow workers to haul stones upwards without needing a very long ramp. Another concept is that a spiral ramp was constructed around the exterior of the pyramid while it was being built. More recently, French architect Jean-Pierre Houdin introduced a theory suggesting that the Egyptians used an external ramp to build the lower levels of a pyramid, followed by a spiraling ramp within the pyramid to transport stones to the top of the structure. This theory is supported by 3D simulations and some physical evidence found within the Great Pyramid.

Researchers present an updated version of the internal ramp theory to explain how the Great Pyramid may have been constructed
History for GRANITE. (2022, November 23). Updating the Great Pyramid internal ramp theory [Video]. https://www.youtube.com/watch?v=_JlnMs616Z0

In addition to ramps, some theories propose that the Egyptians may have used mechanical devices like levers, counterweights, or lifting machines to help move the massive stones. One of the oldest ideas comes from the Greek historian Herodotus, who described a machine made of short wooden beams that may have worked like a cradle or lever. He believed the Egyptians used several of these machines to lift each block step by step as the pyramid rose. Other ideas suggest workers used seesaw-like levers to raise stones, or counterweights to make lifting easier and reduce the amount of human labor needed. These approaches would have helped move the stones more efficiently, especially as the pyramid got taller.

An exploration of the physics behind the construction of the Great Pyramid, focusing on the Herodotus machine and lever systems.
Dr John. (2023, November 18). Physics Reveals How the Pyramids were Actually Built [Video]. YouTube. https://www.youtube.com/watch?v=5amZC1RteA4

One of the most significant engineering aspects of pyramid construction is the level of precision required in the cutting and placement of the stones. The ancient Egyptians had a limited tool set, which included dolerite pounders, copper saws and chisels, wooden wedges, rope, and stone plumb bobs. To extract the limestones from the quarries, the Egyptians used dolerite pounders. Dolerite, a hard stone, was pounded against the softer limestones. Eventually, deep trenches were created, which caused the limestones to detach. The granite, much harder than limestone, was extracted from quarries using a method where wooden wedges were inserted into saw-cut slots. The wedges were then soaked with water, causing the wood to swell and split the stone. To shape the stones, the Egyptians used copper chisels and saws. Although copper is softer than stone, it is effective when used with sand because sand, made predominantly of quartz, is abrasive. The sand was placed between the cutting tool and the stone. The sand particles helped grind down the stone as the tool was worked back and forth in a sawing motion.

Diagram of Egyptian Tool Set

by Warren Volles

Additional Insights

The Egyptians' understanding of astronomy enabled them to align the pyramids with the cardinal directions. By observing the rising and setting points of the sun and stars, they could determine the north-south and east-west lines. Rope stretchers made certain that the square base of the pyramid formed precise right angles. They were workers who specialized in using ropes to measure and layout accurate right angles. They used a method known as the "rope stretching technique," which involved a length of rope tied into a loop and divided into 12 equal sections (units). By forming a triangle with sides measuring 3, 4, and 5 units, they could create a perfect right angle between the sides of 3 and 4. This technique is based on the properties of a 3-4-5 Pythagorean triangle. To achieve the precision seen in the tight joints, which often are not wide enough to fit a credit card, it's likely that the Egyptians used leveling and aligning tools made from wood, as well as plumb bobs made of stone.

A math-based explanation of the design precision behind the Great Pyramid
Cuemath Studio. (2023, February 14). The Egyptians knew it! [Video]. YouTube. https://www.youtube.com/shorts/tGtz5d_ASCI

References

Brier, B., & Houdin, J-P. (2008). The secret of the great pyramid. Smithsonian Books. https://archive.org/details/secretofgreatpyr00brie/mode/2up

Cuemath Studio. (2023, February 14). The Egyptians knew it! [Video]. YouTube. https://www.youtube.com/shorts/tGtz5d_ASCI

Dr John. (2023, November 18). Physics Reveals How the Pyramids were Actually Built [Video]. YouTube. https://www.youtube.com/watch?v=5amZC1RteA4

Fall, A., Weber, B., Pakpour, M., Lenoir, N., Shahidzadeh, N., Fiscina, J., Wagner, C., & Bonn, D. (2014). Sliding friction on wet and dry sand. Physical Review Letters 112, 175502. https://doi.org/10.1103/PhysRevLett.112.175502

Handwerk, B. (2023, December 20). The Pyramids at Giza were built to endure an eternity—but how? National Geographic. https://www.nationalgeographic.com/history/article/giza-pyramids

History for Granite. (2022, November 23). Updating the Great Pyramid internal ramp theory [Video]. YouTube. https://www.youtube.com/watch?v=_JlnMs616Z0

Houdin, J.-P. (2023, March 12). The big void. https://www.academia.edu/98453619/The_BIG_VOID_En_Updated_on_03_12_2023

McCoy, T. (2014, May 2). The surprisingly simple way Egyptians moved massive pyramid stones without modern technology. The Washington Post. https://www.washingtonpost.com/news/morning-mix/wp/2014/05/02/the-surprisingly-simple-way-egyptians-moved-massive-pyramid-stones-without-modern-technology/

Sheisha, H., Kaniewski, D., Marriner, N., Djamali, M., Younes, G., Chen, Z., El-Qady, G., Saleem, A., Véron, A., & Morhange, C. (2022). Nile waterscapes facilitated the construction of the Giza pyramids during the 3rd millennium BCE. Proceedings of the National Academy of Sciences of the United States of America, 119(37), e2202530119. https://doi.org/10.1073/pnas.2202530119 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9477388/

Smithsonian. (n.d.). The Egyptian Pyramid. https://www.si.edu/spotlight/ancient-egypt/pyramid

Tasellari, A., & Erjon Kaiku, E. (2012, May 10-11). How the Great Pyramid of Giza was built: An engineering view [Paper presentation]. International Students’ Conference of Civil Engineering, ISCCE 2012, Epoka University, Tirana, Albania. https://www.researchgate.net/publication/362620058_How_the_great_Pyramid_of_Giza_was_biult_An_engineering_view

Tomb of Djehutihotep. (c. 1880 BCE). Workers transporting a statue on a sled [Wall painting]. Tomb of Djehutihotep, Dayr al-Barsha, Egypt. Reproduced from Griffith Institute, University of Oxford. https://www.researchgate.net/figure/A-wall-painting-from-1880-BC-on-the-tomb-of-Djehutihotep-9-A-sledge-with-a-big_fig2_341599449