Cheops Pyramid: Engineering scientists from Kassel provide surprising insights into the closure of the burial chamber

With the demonstration, Dorka provided important insights into the locking mechanism in the so-called dropstone chamber in the heart of the pyramid. In this single entrance to the burial chamber of Cheops, three granite blocks weighing several tons were lowered one after the other after the burial of the pharaoh around 2500 BC to seal the chamber for all eternity. "The sealing of the burial chamber was a significant ritual act that demanded an appropriate procedure. For the godlike Cheops, a mechanism was specially redeveloped for this purpose, which must have made a magical impression at the time. They didn't just close the door," Dorka explained.

But how were the stones lowered after burial - in a confined space and without machines? According to the findings of the Kassel-based engineering scientist, the secret lies in clever guidance of the hemp ropes that loop around the blocks and keep them suspended: As a result, the friction between the rope and the blocks is so high and the cuboids are slowed down so much that two people are enough to lower them in a controlled manner. Rollers or other moving parts were not necessary.

For his investigations, Dorka faithfully reconstructed the falling stone chamber, i.e. the passage between the burial chamber of Cheops and the so-called "Great Gallery" of the pyramid - including grooves and other important details of the closure device. The closure blocks themselves and their suspension have been lost over the millennia, but can be easily reconstructed: The three granite blocks, each weighing 2.5 tons, were suspended from four ropes running over round timbers. Such round timbers are found in the older pyramid at Meidum, where they are stored immovably and copper sheets protected the wood from damage by the ropes. That's exactly how Dorka and his team used them here, exploring a variety of possible rope guides. "The technical solutions we present build conclusively on archaeological findings," Dorka says. 

According to the findings, contrary to what is often assumed, no great forces were needed to lower the stones. The measurements revealed only a few 100 newtons at the ends of the rope, as Dorka and his team demonstrated this Friday at the University of Kassel. This is due to the friction between the rope and the block. "We have shown that you practically only have to trigger the mechanism. The rest is taken care of by the  ingenious design of the writers at the time. They obviously knew how to use their key technologies excellently,"  says the Kassel scientist. According to Dorka, moving rollers were not one of them: "They would have needed high-performance bearings with these weights. And there is no archaeological evidence for that at all from that time."

Dorka heads the steel and composite construction department at the University of Kassel's Institute of Structural Engineering. His research focuses on securing ancient structures. For example, he has already developed a securing system against earthquakes for Greek temples. "Engineering can make extremely valuable contributions to archaeology by testing technical hypotheses with its methods," explains Dorka. "So far, this is still done far too rarely."

Incidentally, the elaborate sealing devised by the pyramid's builders did not have the desired effect: Cheops' burial chamber was looted thousands of years ago.

Contact:

Prof. Dr.-Ing Uwe Dorka
University of Kassel
Department of Steel and Composite Construction
E-mail: uwe.dorka@uni-kassel.de

Sebastian Mense
University of Kassel
Communication, Press and Public Relations
Tel.: +49 561 804-1961
E-Mail: presse[at]uni-kassel[dot]de
www.uni-kassel.de