Friday, October 05, 2012

The Pantheon: Crown Jewel of Roman Concrete

The Pantheon: Crown Jewel of Roman Concrete


By David Moore
Constructor Magazine (September 2002)
Pantheon Rome
Pantheon Rome (Photo credit: Wikipedia)
Extract: The entire building was a mystery. As we left, I remarked to my wife, “If we gave the task of designing this building to today’s engineers, they couldn’t do it. There is no steel reinforcing in the dome. It violates our building codes.” But there it was, still standing after almost 2,000 years. With this mystery tucked away in my mind, and with plenty of time in retirement, I returned to the United States, determined to find out more about this marvelous building and its construction. My search led me to realize this building is a window into the past, a near perfect example of the brilliant architectural achievement of the builders of ancient Rome.
In my research on this magnificent structure, I quickly discovered that it is unique in many ways. The architect designed the structure so that it would fully enclose an imaginary sphere, 143 feet (43.3 m) in diameter. It is amazing to think of the mathematics required to locate the construction points on the inside of this ball-like structure. As for size, the clear span of the dome of St. Peter’s Basilica in Vatican City, built some 1,500 years later, fell five feet short of the Pantheon’s. In fact, the clear span of the dome was not substantially surpassed until the adoption of steel and reinforced concrete in the modern era.