While thousands of modern buildings have been flattened by the englade over the centuries, its Great Pyramid remains intact.
Researchers have now discovered one of the reasons for its amazing durability: it was designed and built with structural features that have helped it withstand the destructive energy of the since its construction, some 4,600 years ago, as the tomb of the pharaoh Cheops.
Scientists have discovered that above the critical King’s Chamber there are five hidden chambers that act as shock absorbers, dissipating seismic energy.
This find exemplifies the organizational and scientific skills of the ancient builders, who put together a highly complex supply chain to realize a vision that was destined to stand the test of time.
The X-ray of the 37 seismographs
Scientists assessed its structural dynamics by using devices called seismometers to record ambient vibrations, continuous imperceptible background vibrations created by natural forces and human activity, at 37 locations in and around the pyramid. The monument exhibited a remarkably homogeneous and stable structural response to these shocks, despite its size and complexity, the Reuters report said.
The four sides of the pyramid, which is located in Giza, just outside the Egyptian capital Cairo, and is built from huge blocks of limestone, are each about 230 meters long at the base, while the monument covers an area of about 53 hectares.
It was originally about 147 meters high. Natural erosion over time and the removal, centuries ago, of the smooth outer facing stones for use as building materials, left it at its current height of approximately 138.5 meters. It was the tallest building in the world for about 3,800 years.
The secrets of seismic shielding
Scientists identified several features that gave the pyramid earthquake resistance. It features an ultra-wide base with a low center of gravity, highly symmetrical geometry, a gradual reduction in mass towards the top, and a sophisticated internal design, including internal chambers that dampen vibration amplification. It was also built on a strong limestone foundation.
“These elements together create a well-balanced, coherent structure,” said seismologist Mohamed ElGabri of Egypt’s National Research Institute for Astronomy and Geophysics (NRIAG), lead author of the study published Thursday in the journal Scientific Reports.
“Ancient Egyptian builders clearly possessed practical knowledge about stability, foundation behavior, mass distribution and load transfer,” said Asem Salama, NRIAG seismologist and lead author of the study.
Learning through “trial and error”
The researchers found that most of the vibrations recorded inside the pyramid had a frequency that indicated the mechanical stress (stress) was evenly distributed throughout.
“So while I would be hesitant to claim that they deliberately designed the pyramid specifically for earthquake protection, I do believe that they developed architectural and geotechnical solutions that naturally produced structures with exceptional long-term durability,” said Salama.
This was learned over time through trial and error, as evidenced by some of the flawed pyramids that preceded it.
The “hidden” chambers-dampers
The researchers collected seismic data from various passageways and chambers built inside the pyramid, including the main burial chamber called the “King’s Chamber,” as well as the surrounding bedrock and soil.
They found that vibration amplification increased with height inside the pyramid, a normal phenomenon for tall buildings. However, they noticed a decrease in amplification within five special chambers that are built above the King’s Chamber, despite their higher position.
“This suggests that these chambers effectively help dissipate seismic energy and protect the King’s Chamber, one of the most critical areas, from excessive shaking,” ElGabry said.
The most recent major earthquakes in the region include the notable earthquakes of 1847 and 1992, which severely damaged thousands of buildings, with the latter killing more than 560 people. The pyramid suffered minimal damage.
An organizational and administrative saga
It is part of a large complex, along with other pyramids and the Great Sphinx of Giza – all of which have attracted crowds of visitors since ancient times.
“The Great Pyramid is not only an extraordinary engineering achievement, but also a profound work of art and human vision. Its perfect symmetry, monumental scale and elegant proportions create a timeless beauty that continues to awe even after 4,600 years,” said ElGabri.
“Beyond its natural beauty, what impresses me most is the incredible project management and organizational mastery it represents. “Building such a monument took about 20 years and required maintaining a clear, long-term vision, a highly complex supply chain, and coordinating tens of thousands of skilled workers, engineers and administrators,” added ElGabry.
This included managing human resources, training a skilled workforce, ensuring a continuous supply for the workers and logistics for huge quantities of stone.
“It reminds us of what human civilization is capable of when vision, science, organization and determination come together,” ElGabry said. “Indeed they succeeded,” said Salama, “they built a work for eternity.”
