Colosseum Part 1 - Stealing from the Greeks

Pablo Picasso said that “good artists borrow, great artists steal.” I saw first hand how great Christians and Roman architects stole heavily from the Greeks. 

In Siracusa, I entered the Duomo di Siracusa and saw first hand the tripartite origins of the Christian church. The doric columns of the temple of Athena were incorporated into the church structure and left exposed. 

In the outskirts of towns, the Greeks built large semi-circular open auditoria by excavating the stepped seating into hillsides. I saw how the Taormina, Siracusa, Segesta Greek auditoria were sited such that they were rotated away from the axes of distant mountains to create a dynamic tension between the built form and the site. 

Siracusa

Siracusa embedded in hill

Taormina

Segesta

The Romans took the Greek form of auditoria, but modified it to suit their urban life and penchant for munera (gladiatorial contests). Instead of building auditoria into the outlying hillsides and integrating its siting and relationship to the surrounding landscape, the Romans built their auditoria in the heart of their cities from the ground up. Furthermore, the internal north south east west axis of the Colosseum aligns with the ancient cardo decomanus of Rome’s urban plan.

To build up their auditoria, the Romans used brick, stone, and concrete vaults like master builders. The site for the Colosseum was initially a lake in a river valley. To drain the lake, the romans installed 3000 meters of piping and drains 26 feet below the base of the valley to take the water to the Tiber River. Lead piping was used to 20 fountains and toilets inside the Colosseum structure. 220,000 tons of soil were removed from the site. On top of the drained lake, the Romans constructed a 40 foot deep concrete foundation to support the 100,000 cubic meters of travertine stone arches which were used to support the tiered seating. To execute their vaults and spans and foundations, the Romans used opus caementicum, Roman concrete. Unlike modern concrete, roman concrete does not use steel reinforcing, and it uses larger aggregate pieces bound together with cement. As a result, it was laid rather than poured.

Non-stop flow of cartloads of marble, wood, sand, and ingredients for concrete shipped from Carrara, North Africa and Greece were transported to Rome over a 10 year construction period.

Whereas columns in Greece were structural, for Romans, the doric, ionic, and Corinthian columns that line their facades of the Colosseum are half sunk into their walls and thereby decorational. 

Colosseum Part 2 - Roman City Operating System v1.0

Embedded in many European towns, remnants of the Roman City Operating System. At first, Roman planners developed castrum or fortified military camps in their conquest of the world. Later, to efficiently rule the world, Roman planners evolved their castra (off topic trivial fact- any English town name that ends with 'chester' like Manchester used to be a Roman castra) to develop an urban planning strategy that followed these principles: 

(1) The city is composed of standardized parts.
(2) The city is organized according to social, cultural, political principles.
(3) The city accommodates constantly changing flows
(4) The city can be customized to local topographic, climactic, and cultural conditions.

Within the operating system, the following hardware is deployed to sustain the inhabitant and communicate with other cities in the empire:

(1) Basilica is a flexible building used for gatherings and commerce
(2) Capitolium is a temple of state religion
(3) Templa are religious building dedicated to god worship. Usually in the middle of the city
(4) Theatrum is used for games and performances
(5) Thermae are baths that provide city with hygiene service, socialization
(6) Arcus are monuments to commemorate military achievements. Usually located in prominent locations.
(7) Columna has similar function to arcus, used for commemorative purposes.
(8) Aquae ductus is the infrastructure system to transport water.
(9) Limites are the fortifications at the edges of cities like walls and ditches to repel invaders.
(10) Viae are the network of stone paved roads which connect the cities of the empire to each other. Usually 4-6 meters wide.

Cardo et decumanus are the primary perpendicular axes which define center of city. Cardo means hinge in Latin. The magistrate was responsible for determining the center of the new city. Based off the orthogonal axes, centuratio is the process of gridding the land for residential and agricultural purposes.

After the Forum is a centrally located outdoor space (usually situated at the intersection of the cardo et decumanus) for commerce and public social space. Many public buildings like the capitolium, basilica, and templa are adjacent to the forum thereby linking commerce and government. The forum is the place where trading for vases, animals, silver, gold, marble, olive oil, fish, spices, wheat and wine takes place.

Cosa Italy

Pompeii

Timgad Algeria

Valencia, Spain

Barcelona, Spain

Colosseum Part 3 - Sketches

When I first stepped into the Colosseum 16 years ago, I sensed an underlying order. Given the crumbled state of the ruins, however, it was up to visitors like me to piece together the amphitheater and imagine how it once was. Inside the 'arena', which means 'sand' in Latin, which denoted the material that could soak up blood efficiently, 400,000 gladiators and slaves fought to their death to entertain the masses. Their last views on this fair earth were probably the blue sky and thousands of bloodthirsty raucous Romans packed into stands rooting on their warriors. Within the stands, walls and columns laid out in a perfect elliptical grid, and a multitude of stairs fitting within pie shaped wedges of space. As an architect, the real drama of the Colosseum was not in the arena, but under the stairs. As I sketched out spatial order and impressions of habitation, I could imagine concession stands selling grilled Italian sausages, throngs of Romans peeing in the bathrooms, and merchants selling souvenirs to the masses. Strip away the masonry and the walls, and you get a Heatherwick Vessel like hive of circulation.

Now as I revisit the Colosseum from afar, feverishly probing its plans, models, and sections and constructing 3 dimensional computer models trying to piece together its ideal state, I see the Colosseum Operating System more and more clearly. The Colosseum is modular Roman construction pushed to its logical extreme. Radial walls and columns define 80 bays within an elliptical grid. Within the grid, 4 typical pie shaped sections are deployed: (1) straight run stairs, switchback stairs, main north south west east entries, and radial passages. The spatial complexity of the Colosseum is surprisingly derived from only 4 typical sections for (color coded within the video) that are deployed within the bays and interconnected.

Colosseum Part 4 - Drawings

To write about how Lou Kahn's experience in Rome impacted his designs in terms of geometry, organization, column spacing, and structure,  (i.e., Salk Institute), I've dived into drawing the Colosseum. Online, there is surprisingly scant information about the famous amphitheater. Complicating matters is that the plans, and sections that are available conflict. The contradictory nature of drawings is probably due to the fact that the structure lies in ruins... it is up to the architects and artists to hypothesize and fill in the blanks to what was once there.

sangallo sketch

I found 2 clues to start my drawing: first, the Colosseum has 80 arches on the exterior ground floor. the clear opening between the arches is 13'-9", second, the outer ellipse is 617' by 513', and the interior ellipse is  283' by 178'. Within each of the 80 sections of the Colosseum there are 5 bay types: (1) horizontal passage (2) stairs up to 2nd level (3) switchback stairs up to 2nd level (4) switchback stairs down from 2nd level (5) stairs up to ring side seats. (marked in yellow below) That is the beauty of Roman architecture, within a 'simple' geometric order is variation that provides spatial complexity and function. It's said, the Colosseum could be cleared out in 12 minutes due to its vertical circulation design.

ground floor plan

top floor plan in progress

Surprisingly, my efforts in understanding and drawing the upper mezzanine levels of the Colosseum (which no one has done before) is riding on Vicenzo Lunardi, the man who pioneered hydrogen balloon flight.  He drew crowds of 200,000 to watch him take flight in London in 1786.

In 1788, Carlo Lucangeli, architect and cabinet maker from Rome (1747-1812) took part in the test flights of Lunardi near the Mausoleum of Augustus, Rome. After several unsuccessful attempts to take off, the balloon took of with Lucangeli unintentionally aboard. He became the first person to fly over the city of Rome, including the Colosseum. The aerial perspective of the Colosseum inspired Lucangeli to devote the next 22 years of his life 1790 to 1812 to study the Colosseum. He carried out excavations of the hypogea (underground gladiator chambers) and paintstakingly made a wood model of the Colosseum at 1:60 scale is 8' by 10' by 3' high and is comprised of 70' annular pieces which fit can be disassembled to show interior circulation and sculptural details. It shows the Colosseum in it's ideal completed form, with 22 years of surveys and knowledge of the site embedded in its proposed configuration. Lucangeli's brother-in-law finished the model, Mussolini painted it over in white paint... today the model sits in the Colosseum museum. Currently, teams of Italian researchers have been photographing it, digitizing it in 3 dimensions, and writing about it for the past 10 years to gain an understanding of the Colosseum structure.