No history of engineering would be complete without a look at how the Egyptian pyramids were built.
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Key Takeaways
- The Egyptian pyramids are the last remaining of the Seven Wonders of the Ancient World.
- Archaeological evidence shows that the pyramids were built without sophisticated mechanical tools, with builders learning from each monument to refine techniques.
- The pyramids demonstrate the Egyptians' extraordinary skills in mathematics, astronomy, logistics and advanced engineering.
The
Egyptian pyramids, represented most famously by the pyramids at Giza, are perhaps the most enduring and iconic vestige of the ancient Egyptian civilization. How the pyramids were built, however, remains a source of intense speculation among historians, archaeologists and engineers.
The scale and precision of the pyramids demonstrate the Egyptians' extraordinary skills in mathematics, astronomy, logistics and advanced engineering. Unfortunately, the Egyptians did not devote the same level of effort to documenting their planning and construction processes. Much of what we know about how the pyramids were built, therefore, comes from observations made and artifacts unearthed by
archaeologists at Giza and other Egyptian pyramid sites.
Lessons From History
To understand how the pyramids were built is to understand the history of engineering in the Old Kingdom of Egypt, a period spanning 2575 to 2134 B.C.
The three major pyramids at Giza were designed and built to serve as tombs, respectively, for Egyptian pharaohs Khufu, his son Khafre, and Khufu's grandson, Menkaure, between 2540-2460 BC, explains engineer Craig B. Smith in his book "How the Great Pyramid Was Built." These structures represent the pinnacle of Egyptian pyramid building, but their stature as engineering wonders is built on a foundation of lessons learned from the construction of earlier, less famous pyramids.
Advanced Engineering
One of the earliest Egyptian pyramids, for example, is the Step Pyramid begun by Pharaoh Djoser in 2620 B.C. at Saqqara. Its series of stepped, concentric platforms represented the first significant architectural departure from early Egyptian tombs, which featured flat, slightly raised platforms known as mastabas, according to Smith.
Another major step forward in the history of engineering came with the pyramid at Meidum begun by Pharaoh Sneferu in 2570 B.C., Smith details. It was the first pyramid to incorporate corbelled ceilings in underground chambers, an approach that afforded elegant, arched ceilings. Unfortunately, this pyramid, like the Step Pyramid, achieved its sloping exterior shape with courses of inwardly leaning stones, an engineering approach that would prove untenable.
A More Level Approach
The Bent Pyramid, begun by Pharaoh Sneferu in Dahshur in 2565 B.C., added several critical chapters to the history of engineering, Smith recounts. Its site consisted of loose, sandy soil, a foundation that provided inadequate support for the heavy structure. Predictably, the pyramid began to sink as construction proceeded, a result of using inwardly leaning blocks on an unstable foundation. To reduce stress on the structure, the pyramid's architects and builders reduced the slope of its exterior sides by 10 degrees, which created a "bent" appearance for the upper two-thirds of the structure.
Serendipitously, this structural resolution produced the most significant breakthrough in how the pyramids were built: New courses of blocks (for this and all future pyramids) would be laid horizontally to reduce stress on the pyramid's inner core. And the pyramids' smooth, angled sides would be achieved using horizontal courses of stone finished with angled faces.
Rules to Build By
The Red Pyramid, begun in 2560 B.C. by Pharaoh Sneferu, marked the zenith of engineering lessons learned. It would serve as a prototype for the Great Pyramid, the first pyramid at Giza. It also codified the following lessons for pyramid building, as laid out by Smith:
- Build the pyramid on solid rock to ensure adequate support for its structure.
- Use precise measurements (square, plumb) to maintain the pyramid's shape.
- Place the burial chamber within the pyramid, not in the ground under the pyramid.
- Place masonry courses horizontally to better distribute the loads.
- Use large blocks on the lowest levels to create an accurate and stable base. Use smaller blocks on higher levels as they will be easier to place.
- Use corbelled ceilings to create spacious, dramatic rooms, while providing the structural strength required.
- Select a pyramid angle that minimizes labor and maximizes height.
- Finish the pyramid with fine white limestone to make it visible from great distances.