A Paper from Monika Michutë on architectural aspects
Echoes from the Colosseum: Building today on yesterday
DTCCApril 20, 2004
Dear Cel Brant:
The following is my term paper about the Roman Colosseum. During my research, I have gathered a lot of wonderful information and facts about the ancient engineering and architecture. In addition, the information broadened my knowledge about certain building materials, methods and terminology.
I found it surprising that not many architects or engineers know about old-fashioned building techniques. It was very difficult to find a qualified interviewee on the topic, but Andrea Pepe gave me a very detailed discussion about the Colosseum. Even though he is not a professional archeologist or architect, she is one of the creators of the Web Page www.the-colosseum.net which was as the main source for this research.
I believe that I will be able to incorporate the knowledge I gained in my architectural work in the future. In addition, programs in the colleges should include classes on ancient structural design to broaden everyone’s view. Romans’ passion, precision, and skill reflects in every their building, even after 2000 years. Today’s structures deserve long lasting life and appreciation as well, which can be achieved by combining both modern discoveries and ancient secrets of engineering.
I enjoyed working on this research paper, and I hope you will enjoy reading it just as much. If there are any further questions that you might have, I will be more than happy to answer them.
Table of content
Site and foundation
Shape and basic dimensions
Entrances and corridors
|Over the time
To improve modern structures, knowledge about the ancient engineering methods is important. Roman Colosseum, which was built in less than 10 years and stood for nearly two millennia, is one of the examples to learn from. It was built next to the lake, so drains were installed 8 to 10 m below the arena. When engineers reached the clay bed, they filled a doughnut shape foundation with concrete. Because the first tier of arches was built with travertine stone, construction was carried out at the top and bottom of structure at the same time. Architect is unknown, but his careful details of the design entitle the Colosseum to be “perfect”.
In approximately ten years, ancient Romans managed to erect and complete an enormous structure of the Roman Colosseum, which is also called the Amphitheatrum Flavium. Emperor Vespasian started the building in 72 A.D., while his son, emperor Titus, dedicated it in 80 A.D.. Today, after nearly two millenniums, the Amphitheatrum Flavium still remains one of the oldest, most perfect, and most important examples of architecture and engineering. The unknown architect of the Colosseum considered every detail so carefully and precisely, that building conquered the biggest two enemies: a destructive nature of a human and time.
An unsuccessful search for qualified interviewees about the Colosseum showed that there is only a fraction of architects who would know about the ancient engineering methods. In addition, many of today’s modern buildings fail ‘young’ or while being built. For example, the 5-story garage belonging to the Tropicana Casino in Atlantic City, NJ collapsed during the construction.
The idea of combining modern achievements in engineering and architecture with the ancient world’s secrets is reasonable. It is impossible to uncover every detail of the Colosseum’s design and construction because it was built so long ago. However, learning the major discoveries that the archeologists have found over the centuries is crucial.
After numerous uprisings and disasters in Rome, Vespasian was loosing his fame as an emperor. To regain Romans favor back, he decided to give his nation a public building as a “present” to them. The Colosseum was to be built on the land previously taken away from the Roman people, where emperor Nero had his palace (“Colosseum: Gladiator’s Story”, 2004). As the Professor Andrew Wallace-Hadrill said to the BBC News correspondent B. Baron (2004), “emperors depended crucially on the Colosseum for their fame.”
The Colosseum served its political and public purpose well. “Munera” (gladiator fights), “venationes” (wild animal hunts), and “naumachiae” (naval battles) were the major “games” that attracted approximately 55,000 people each time for bloody entertainment . Thumbs up from the emperor meant life for the looser gladiator, while thumbs down meant death. About 90% of the gladiators were granted the thumbs up sign (“Colosseum: Gladiator’s Story”, 2004).
On the present location of the Colosseum, emperor Nero had his “Domus Aurea” (Golden Palace) with huge gardens around it. After Nero’s death, Vespasian decided to give this land back to the Roman people in a shape of public building. The site was surrounded by four hills: Palatine, Velia, Esquiline, and Celio. It was on the shore of a little Nero’s lake, which during certain seasons caused the site to become a wetland.
Drainage and foundation had to be engineered very carefully because of the heavy superstructure for this type of land. To prevent the future settlement of a building, Romans reached a clay bed at the bottom of the lake, which was the major support for the foundation. Enormous drains were located the way, that no matter what “…the bottom of the arena remains 10 meters above that of the drain”. Below is Keith’s Hopkins’s (2003) description of the foundation:
… drains were built 8m (26ft) underneath the structure, to take away the streams that flow from the surrounding valleys and hills. Then foundations, roughly in the shape of a doughnut, made of concrete: under the outer walls and seating, they are 12-13m (39-42ft) deep, while under the inner ellipse of the arena, they are only 4m (13ft) deep, and designed in strips beneath each of the concentric walls. (See Figure A)
The excavation area had a perimeter of 530 meters (1739 ft). It was filled up with Roman cement, mortar, and limestone. For additional firmness and strength, Romans hammered all three materials. “The entire base of the Colosseum was equivalent to 6 acres” (“Communication,” 2004).
To make the excavation less labor intense, Romans used the excess soil and “waist materials” from the previously existing houses. By adding all this spoil around the excavation, Romans lifted the level of the site and deepened the foundation by approximately 11 meters (36 ft) (Hopkins, 2003).
Engineers reinforced the foundation by two 6 meters (20 ft) deep and 3 meters (10 ft) wide brick walls. While one of the walls follows the outer layout of an ellipse shape of the foundation, the second wall follows the inner ellipse, directly under the arena.
It is known, that during dedication of the Colosseum in 80 A.D., Titus staged a ship-battle scene in the amphitheatre. The arena was filled with water, about one meter deep, therefore, basement could not exist jet (Hopkins, 2003).
Within a year or two, emperor Titus built so called “subterranean area”, which laid directly on the foundation. It contained everything that was necessary to make the preparations comfortable and the performances satisfying the spectators: rooms for gladiators, cages for wild animals, stage scenery equipment, and decorations, special machinery for animal control, elevators, etc. (Velius, 2001).
The top elevation of the basement is like a maze. Numerous narrow passages were utilized to lead animals to their cages or elevators, so that the main corridors remained safe and free for circulation. Most of the substructure walls follow the elliptical shape of the Colosseum, while others, however, “are parallel to the major axis.” Standing on the brick pavement base and holding wooden floor of the arena from the top, these walls reach up to 6 meters (20 ft) height (Platner, 2003).
The Colosseum has its own original shape of an ellipse. It was designed by combining two semicircular theatres facing each other (see Figure B) (Velius, 2001). Jones M. W. (2000, p.88) suggests the way of drawing the shape of the amphitheatre using a “Pythagorean-triangle-and-inscribed circle” scheme:
- Locate the major (x-x’) and minor axis, similar to the coordinate system. Then, draw a right triangle with 3:4:5 ratio, so that the 90° angle occurs on the origin (0;0)
2. Continue drawing triangles as in step one for the remaining quadrants. The sides of the triangles should be extended at the points A and A’ each way. It will set the boundaries for the ellipse.
3. Distance A-A’ is set to be equal to the width of the arena, which is centered on the minor axis and indicated with points C and C’. Then, draw an arc so that it crosses points C and C’ while the center of an arc is B’ and B respectively. Close the end of an ellipse by drawing an arc from point d1 and d2 with the center being A’. Repeat it for the opposite side as well.
4. For the rest of the structure, the width of the cavea has to be determined (in this case the width of the cavea is equal to the width of the arena). Follow similar method as for drawing arena (step 3).
The major axis of the Colosseum measures 188 m (617 ft) and it is oriented WSW-ESE, while the minor axis is 156 m (512 ft) long. The height of the Colosseum reaches 48.5 m (159 ft)(Pepe A., Pepe D., and McElwee, 2003).
The first (ground) floor contains of 80 arch entrances divided evenly along the perimeter, which is build in Doric style (Hopkins, 2003). Arcs are 4.20 m (14 ft) wide and 7 m (23 ft) high. The pillars in between the arches are 2.40 m (7.87 ft) wide and 2.70 m (8.85 ft) deep with a column of them (Platner, 2003).
Arches of all three floors differ in order. Second and third floors are built Ionic and Corinthian styles respectively. They also are smaller than those on the ground floor, reaching the height of only 6.45 m (21 ft). Between each pillar is a half column. The fourth floor has no arches, but rectangular windows instead; a window above every other arch of the third story.
Romans covered the foundation by 90 cm thick travertine layer. “The base blocks of the pillars were anchored to the floor by pivot and melted metal” in previously marked locations. Builders could perform construction on the first and second floors at the same time. They raised the “skeleton of pillars” to the second floor and cemented them with 2 ft long brick arches for firmness. While still working on the ground floor, construction of the “rampant vaults” for the cavea and seat support could be carried out on the upper levels as well.
According to the interviewee Andrea Pepe, this original construction method is the greatest structural detail of the Roman Colosseum:
In my opinion, the most outstanding factor is the building technique, i.e. doing the first rounds of arches in travertine so that the completion of the construction could take place at the same time above and under this first structure. It took only 10 years to build! (For full interview see Figure E)(Personal communication, March, 2004)
So that arches would be able to carry heavy loads (especially the ones on the first tier), Romans used the keystone technique, which allowed transmit forces from the top of an arch to its footing. Because of its shape, the keystone transmits forces to the “voussoir blocks”, which during construction are temporarily supported by a wooden frame. From the Voussoirs forces travel through the impost to the pier until it finally reaches the foundation of an arch (Crystal, 2004).
Pillars on the first floor were filled up with tufa, while the ones on the second floor received “cement aggregate” with “brick facing”. A lot of stone at the higher levels of the Colosseum was recycled from other buildings; for a firm block connection, Romans used metal clamps.
While the first tier of arches rests on the base of two steps, second and third floor columns lay on the pedestals (Smith, 2004). The unknown architect calculated the biggest pressure to fall on the first and second stories. For that reason the largest blocks of travertine make the exterior of an amphitheatre, while smaller ones are in the interior. The rest of the building Romans finished with “blocks of peperino and concrete” (Platner, 2003).
Next to the overall structure, fourth story looks modest. It looked like an attic, without corridors, and with Corinthian pillars resting against the walls (Smith, 2004). Three consoles were placed between each pair of pillars, right above the windows. Consoles contained sockets for the wooden posts holding velarium (awning) (see Figure D) (Platner, 2003).
Each arch of the second and third floors held a statue of either emperor or god, while bronze shields decorated exterior walls. White marble covered the seats and walls; sealing were ornamented with painted stucco. Higher floors, however, were less decorative, because it was dedicated to the lower class spectators (Hopkins, 2003).
According to the archeologists’ discoveries, Vespasian was responsible for the first two rows of the arcades to be built. He dedicated the Amphitheatrum Flavium right before his death, in 79 A.D. His son Titus added third and fourth stories. He expanded seating for lower class Romans and dedicated it with 100 day games in 80 A.D. Vespasian’s other son Domitian finished clipea and decorated the exterior of the building with bronze shields (Platner, 2003).
Some sources claim, that slave labor was used for the most of the construction, because the amphitheatre was erected so fast. Others, however, say that the Colosseum is too perfect to be built by slaves. For the interview, Andrea Pepe said that workers were skilled, and slaves only did rough stone cutting (personal communication, March, 2004), when Mark (marq78, personal communication, March 10, 2004) claims, that slaves did the majority of work, just like for any other building in Roman empire (for a full interviews see Figures E and F).
Romans used a variety of materials, most of which were different species of stone. The actual stone was determined by the loads to be carried:
They are used based on how much of a load they can support. Travertine is at the lower levels, as it can support the most, and tufa and brick are found in areas that require less loading. (Personal communications, March 10, 2004)
Some travertine blocks were cut into pieces of 5/10 feet. Each one of them was marked to indicate its exact location (Smith, P., 2004). Tufa was used to fill in the gaps, while cement was perfect for vaults because of its light nature (personal communication, March, 2004). Romans consumed about 300 tons of metal for the clamps connecting the blocks (“The Roman Colosseum”, 2001). Most of the stone was quarried in the lands of the Roman Empire. For convenience, a direct road was build from the travertine excavation site to the building area.
80 arch entrances let the spectators and performers into the Colosseum. 76 public entrances were marked from I to LXXVI (1-76) counter-clock wise, while the four at each axis were unnumbered (Hopkins, 2003). Emperors and other nobles utilized the unnumbered entrances at the short axis of the amphitheatre. One of the entrances led directly to the imperial box, and another to a similar seat for the emperor’s guests. Entrances at the long axis of the Colosseum were dedicated to the gladiators, their teachers and owners (Platner, 2003). The western arch was called “Libitinarian Gate.” To honor deceased gladiators and killed animals, they were carried out through this gate (Crystal, 2004). The opposite entrance leads directly to the arena and subterranean area (Platner, 2003).
There is a pattern of 5 different entrances to the amphitheatre, which is repeated all around the perimeter. The 12 “b type” paths led to the lower senators’ seats, and 16 “d” corridors led to the upper senators’ seats. 20 “a” paths led to the “maenianum primum” and to the upper sections. 16 “c” and 16 “e” paths led to the same corridor of the “a type”.
Corridors were “running uninterruptedly round the building, behind which again is another precisely similar corridor” (see Figure C) (Smith, 2004). About 5.8 m (19 ft) towards the inside from the outer wall of the Colosseum, there is another similar wall, and about 4.5 m (15 ft) further, there is one more, creating two main passageways of the ground floor in between. Almost directly above, on the second and third floors, similar corridors are located (Platner, 2003).
The first corridor, at the outer rim of the amphitheater controlled main circulation. Eighty walls dividing the space behind the second corridor served multiple purposes. It supported the structure, then, part of it was a direct path to the upper floors of the Colosseum, and second part of it took to a similar third hallway. Fourth corridor is slightly smaller, because one of its walls is the same as podium, which is thicker than the rest of the walls. The entire space under the cavea was dedicated to the easy and quick circulation of the spectators (Smith, 2004).
A long axis of the arena is about 80 m (258 ft), and short one is about 46 m (150 ft). The wall surrounding it is called “podium”. It is about 4.5 m (15 ft) high and on the top holds first few rows of the spectator seats as well as the imperial box (Velius, 2001). For additional protection from wild animals, a further fence was erected inside the arena (Hopkins, 2003).
The wooden floor was covered with about 15 cm of “harena” (sand) to absorb gladiator and animal blood. Sometimes the sand would be already painted in red to cover the natural color of blood (Hopkins, 2003). It also was hiding numerous trap doors for the animals to appear in the middle of the fight scene (Scott [director], 2000). So that animals would not jump over the podium, trained archers sat in the niches placed in the service tunnel between the podium and arena.
During the first year after dedication, naval battles were performed in the Colosseum. Before the games, wooden floor would be removed and the arena would be filled up with water. Since it required long and careful preparation, naval battles were removed to another site (“The Coliseum of ancient Rome,” 1997).
About 10,000 slaves, war prisoners, and volunteers were killed in the arena of the Colosseum. The last gladiator fight was in 404 A.D., but animal hunt shows were held until the 6th century (“The Coliseum of ancient Rome,” 1997).
A clear distinction between the classes of the citizens was very important in ancient Roman society. The seating arrangement in the Colosseum reflected this culture.
The first two to three rows on the podium were dedicated to the senators with their personal chairs. Emperor sat on the podium as well, in his personal imperial box.
High-class citizens, such as knights and other rich Romans sat at the second level called “maenianum primum.” Third level was divided into tree more parts. “Maenianum secundum imum” was for the middle class citizens and military men. Low-class Romans had their seats assigned at the “maenianum secundum summum”, while very poor and women were not allowed lower than to the forth story to the standing area only, “maenianum summum in ligneis”.
Noble ones enjoyed white marble seats; some of them were with cushions. Lower class Romans watched the games sitting on the wooden benches (“The Coliseum of ancient Rome,” 1997). Architect designed the building to hold about 55,000 spectators, which was possible. But “except for the front rows on the podium, spectators were packed like sardines in the tin” left with about 40 cm of space per person (Hopkins, 2003).
Above the “maenianum summum in ligneis” a platform was built. Archeologists predict it to be a space for sailors, who maneuvered velariums (awnings). 240 wooden posts supported velarium at the top of the Colosseum while stones in the ground held the ropes to assist the sailors. Although it has not been proven, that stones around the building were necessarily used for the awnings (personal communication, March, 2004).
Velarium protected the spectators from the burning summer sun. It also provided cool air for the cavea. Because of the hole in the middle, it “sloped down towards the center to catch the wind and provide the breeze for the audience” (Communication, 2004). Awnings covered about one third of the inside because of the limited length of the post supporting it (Hopkins, 2003).
The Amphitheatrum Flavium lived through multiple disasters. In 217 the upper floor caught on fire. Three earthquakes in 442, 470, and 847 weakened the structure. It served as a living are and a fortress in the middle ages. During the Renaissance, part of the stone from the Colosseum was recycled for other buildings. Because of the drainage failure, passages of under the arena filled up with dirt. Earthquake in 1231 destroyed a big part of the wall from the Southwest side.
At the beginning of the nineteenth century, restoration works began. Firstly, remains of the outer wall were reinforced. In 1840’s more arches were restored, and in 1870, half the debris was removed from under arena. A lot of restoration jobs were performed since WW2 with the major project in 1978. Then more arches were rebuilt. Small works on the Colosseum continued up until the year 2000.
Travertine pavement around the Colosseum in the shape of square is the only spot, which remains at the same level as in the antiquity.
Only 32 arches on the northern side (XXIII to LIV) still exist. The original arena floor is long gone, but a wooden stage was built a couple years ago, where modern performances are being held (Barron, 2004). Marble no longer covers amphitheatre’s walls or seats. Archeologists have only found 65 capitals of columns, 9 bases of columns, pieces of cornices and consoles, and fragments of the barriers.
Recently, the mayor of Rome, Valter Veltroni, and architect Aymonino considered the reconstruction of the Colosseum. To redesign the area around the arena, rebuild the missing wall with red brick is in their plans (for more comments about the article see figure C, question 8) (Willey, 2004).
In the eyes of Gibbon, the Colosseum is perfect: “Nothing was omitted, which in any respect could be subservient to the convenience and pleasure of the spectators” (Smith, 2004). It also is perfect structurally. Not many buildings across the world can carry that label of “perfect,” especially today. Ancient engineering methods seem to be ignored by many builders. A closer look, however, could improve and provide more structural, as well as visual, flexibility to their creations.
Anonymous. (1997). “The Coliseum of ancient Rome.” Retrieved February 6, 2004, from http://www.eliki.com/ancient/civilizations/roman/
Anonymous. (2001). “The Roman Colosseum.” Retrieved February 11, 2004, from http://www.allsands.com/Travel/Places/theromancolos_ytg_gn.htm
Barron, B. (2004 Jun 19). BBC news. “Glory returns to Coliseum.” Retrieved March 2, 2004, from http://news.bbc.co.uk/1/hi/world/europe/797277.stm
Communication. (2004). “Roman architecture”. The history of western architecture: Roman and early Christian: republic and empire. Retrieved March 17, 2004, from http://lilt.ilstu.edu/bekurtz/roman_architecture.htm
Communication. (2004, Jan 31). The free encyclopedia. “Roman Colosseum.” Retrieved February 11, 2004, from http://en.wikipedia.org/wiki/Roman_Colosseum
Crystal, E. (2004, Mar 16). Ancient Rome. “Ancient Roman architecture”. Retrieved March 17, 2004, from http://www.crystalinks.com/romearchitecture.html
Discovery Channel (2004). Colosseum: a gladiator’s story [Television series]. United States: Discovery Communications Inc.
Hopkins, K. (2003, Sep 25). BBC history. “The Colosseum: emblem of Rome.” Retrieved February 7, 2004, from http://www.bbc.co.uk/history/ancient/romans/colosseum_01.shtml
Jones, M. W. (2000). Principles of Roman architecture. New Haven and London: Yale University Press.
Payne, R. (2004). “Architects of empire.” In Hale, W. H. & editors of Horizon Magazine (Eds.), The horizon book of ancient Rome (242-243). New York: American heritage publishing co.
Pepe, A., Pepe, D., and McElwee, C. (2003). The Colosseum. Retrieved February 11, 2004, from http://www.the-colosseum.net/idx-en.htm
Platner, B S. (2003, Dec 17). “Amphitheatrum Flavium.” Retrieved March 8, 2004 from http://www.ukans.edu/history/index/europe/ancient_rome/E/Gazetteer/Places/Europe/Italy/Lazio/Roma/Rome/.Texts/PLATOP*/Amphitheatrum_Flavium.html
Scott, R. [director]. (2000). Gladiator [Motion Picture]. United States: Universal Pictures and Dream Works.
Smith, P. (2004, Jan 13). “Amphitheatrum”. Retrieved March 3, 2004, from http://www.ukans.edu/history/index/europe/ancient_rome/E/Roman/Texts/secondary/SMIGRA*/Amphitheatrum.html
Velius G. (2001, Aug 22). “The Colosseum.” Retrieved March 2, 2004, from http://www.legionxxiv.org/colosseum/
Willey, D. (2004, Feb 20). BBC news. “Plans to restore ancient Rome spur dissent.” Retrieved March 2 2004, from http://news.bbc.co.uk/1/hi/world/europe/3506867.stm
Zoch, P. A. (1998). “The Flavian emperors”. Ancient Roma: An introductory history (259-264). Norman: University of Oklahoma press.�
Figure A: foundation of the Colosseum is doughnut shape. Inner ellipse and major axis are thinner then the remainder of the foundation.
Figure B: the shape of the Colosseum derived from combination of two theatres facing each other. It provided larger arena and more space for spectators.
Figure C: Section and top views provide assistance to clearly visualize numerous corridors running around the Colosseum.
Source: Smith, P. (2004, Jan 13). “Amphitheatrum”. Retrieved March 3, 2004, from http://www.ukans.edu/history/index/europe/ancient_rome/E/Roman/Texts/secondary/SMIGRA*/Amphitheatrum.htmlFigure D: Sockets that held post for the velarium.
Source: Pepe A., Pepe D., and McElwee C. (2003). The Colosseum. Retrieved February 11, 2004, from http://www.the-colosseum.net/idx-en.htm
Andrea Pepe is one of the creators of the Web Page www.the-colosseum.net, which provided the majority of the information for the document. He gave an interview via e-mail to assist in writing this research paper
.Q: According to you, what is the most outstanding structural detail of the Roman Colosseum?
A: There are many: the formal elegance, the solidity of the construction, the organization of the spaces (entrance/exit system, underground spaces for machines and beasts). In my opinion the most outstanding factor is the building technique, i.e. doing the first rounds of arches in travertine so that the completion of the construction could take place at the same time above and under this first structure. It took only 10 years to build it!
Q: Please explain, how did the Romans make the awnings (velarium) effective? What kind of machinery, if any, did they use to assist the sailors?
A: There are many theories about the Velarium, but I find most of them unsatisfactory. We don’t even know for sure if the ropes were attached to the stones placed around the base of the amphitheatre and how they were utilized (see the velarium page). I am ignorant of sailing matters, but I imagine that the vele must have been very very thin, so as to save weight, and that sailors used devices that reduced the effort to pull the ropes (these contraptions then were already known to builders).
Q: From my ancient history classes I recall the fact that there were big pitchers under the spectator seats in the amphitheatres. At first the researchers thought it served as a bathroom, but later it was discovered that the pitchers were used for the acoustical purposes. Could you comment this statement? How did it serve its purpose and it was placed in the structure?
A: I didn’t know at all about this story of the pitchers. Imagine the smell… In the Colosseum they could not have been stored under the seats because there is no “under seat” room. The seats were like steps. For the Colosseum, recent studies have hypotheses that there may have been toilets (which are very reasonable, considering that the games lasted all day long). Maybe for the pitchers the acoustical purpose makes sense (an enormous jug band!).
Q: Someone told me that one of the Colosseum’s mysteries is the bathroom. What would be your theory about the placement of the bathrooms in the Amphitheatrum Flavium?
A: I leave the theories to the experts. They have identified certain places as probable toilets. The fact is that the Colosseum was used for centuries afterwards for different purposes, and many traces of the old fittings have been lost.
Q: Some sources also state that slavery was used to build the Colosseum; other sources however, state that the amphitheatre is too perfect and it was built by the experts. Which theory do you support and why?
A: Slaves may have been used for the menial jobs (manpower, brickmaking, rough cutting of the stones etc.) but the quality of the final construction suggests that the workers were skilled. We understand from little details of the construction that it was subcontracted to 4 different builders, one for each quadrant. Keep in mind that building in general was an art in which ancient Romans were experts. They really built things to last for centuries, as it is witnessed by innumerable remains all around the Mediterranean.
Q: During my research I found that the reason the Colosseum is structurally strong and still remains is the different materials used such as tufa, travertine, brick, and cement. How do all these different materials work together?
– Travertine is extremely solid and can stand a very heavy weight.
– Tufa is a good rock for filling spaces and some types of it are very resistant.
-Bricks are adaptable and light.
– Cement was used for the vaults since it is very light if mixed – as they did – with pumix stone, and is fast to cast.
Q: Isn’t it important to take into account the different expansion factors, resistance, etc., of the different materials while designing the building?
A: Yes of course. Especially resistance, in the case of the C… That is why the main structure is made of very resistant travertine, and the other structures were built afterwards. In any case they are all “stone” materials. I imagine that with modern materials like concrete, steel and glass the expansion factor is much more critical.
Q: Right by the Colosseum there is one of the main roads. Constant traffic moves around the foundation of the Colosseum. What kind of the major damage does the traffic do to the Roman Colosseum and how can it be prevented?
A: In my opinion the biggest damage to the foundations may be caused by the underground railway line that passes very near the Colosseum with very heavy coaches. The motor traffic may shake the foundation a little, but great damage is caused by the smog, that attacks the travertine and corrodes it. There have always been projects to isolate the Colosseum from the traffic (the latest one re-emerged a few weeks ago), but to no avail.
Q: BBC News just released the article about the restoration of the Roman Colosseum with the red brick? Have you heard anything about it, and what would be your position in this issue?
A: I did not really follow this story then (we have heard so many during the years!!), but I found the article and these are my comments:”Plans to restore ancient Rome spur dissent By David Willey
BBC correspondent in Rome”
“Controversial plans are afoot to revamp Rome’s historic center – to give visitors a better insight into how the ancient city looked.
A 78-year-old Italian professor of architecture, Carlo Aymonino, has been entrusted by the city’s mayor with redesigning the area around the Roman forum – once dominated by a soaring, white marble temple.”The proposal to isolate the Forums, the Colosseum and a big sector of the city from modernity was first advanced by the French around 1810 and since then it resurfaced many times. In my opinion the “Parco Archeologico” would be a good thing for tourists and Romans, but then public transport around and beneath it should be greatly improved, so as to substitute the roads that we use now. My motto is: respect the dead but think about the living! I would substitute the road with an underground line beneath the Forums, under the archaeological stratum, or a kind of tramway, or some innovative mean of transport (like in theme parks). I am strongly convinced that many more underground lines are badly needed in Rome. Road traffic is literally chocking the city, and it also looks lousy.
In any case there is no major consensus in Rome about this proposal, which is one of the many that appear every now and then.
As for the soaring, white temples, there were many of them…”His plan is to do away with the modern road leading to the Colosseum, the ancient Roman amphitheatre where gladiators once fought wild animals – and each other – to entertain the crowds. The modern road, built by Mussolini, covers many important ruins.”It is true that the modern road built by Mussolini covers ruins, but the news are that the recent right wing government has had it declared “monumento nazionale”, so that it got the same status of the most important ancient monuments and it seems that it cannot be touched anymore (at least until there is a right wing government that loves Mussolini and his memories!). In the past few years the spaces right and left of the road (there were gardens) were excavated, but they stopped at the level of 17th century cellars, which is not at all interesting (all you see is a maze of small rooms and walls) and there is no continuity with the rest of the Forums around.”Professor Aymonino also proposes to fill in the missing part of the outer wall of the Colosseum with red brick.”This already happened: the whole inner southern circles were reconstructed in the 19th century with red bricks and nobody notices it! Reconstructing the whole thing would be very expensive!”He wants to clean out the weeds and the rubble nearby and to reconstruct part of the temple of Jupiter – which formed the heart of ancient Rome – adding a transparent dome amid the ruins.”Hmmm, interesting! I think of the Louvre Pyramid! But Italian archaeologists have a very conservative approach about monuments.”Many classical scholars say they are aghast at the idea of turning Rome’s center into what they fear would become an archaeological theme park.”You see? I told you. They are aghast. What’s wrong with teaching Roman culture to tourists by modern means? A theme park gives a service to the customers. In my opinion tourists bring money and should be rewarded. It would be much better if in the big archaeological area there were boards showing how the thing was before, reconstructions, models, a film showing the old Forum and Roman life and customs etc. so that one could understand something instead of watching a sea of crumbled stones. And of course also bars, restaurants, toilets.
Until the 70s in the Forum, amidst the ancient columns, there used to be a Sound and Light shows with music and stories of ancient Rome. Tourists literally loved it. Ruins are much more interesting if you understand how they were when new.”In modern times, Romans have hotly debated how – and whether – to restore ancient monuments.For many centuries they simply ripped apart the ruins of imperial Rome and recycled the building materials for new palaces and churches. Most modern archaeologists prefer minimalist restoration.” (Story from BBC NEWS)
A: My position in general is that restorations should appear as such (I think that this is has been for long the trend in archaeology) and should not try to be concealed. In any case one should not try to reconstruct structures when the original appearance is unknown (I think of Knossos, in Crete, a Hollywoodian reconstruction).
Q: Is it possible to restore the Colosseum so that structurally it would look and serve as it did in the ancient times? Why? (How?)
A: Yes, it would be possible to restore the monument in this way, but it would be very very expensive and time consuming. As to the why, it would be to produce shows. As to the how, it would not be at all impossible with modern means.
Q: Currently, there is a new wooden stage being built on the ruins of the old one, which will be used for modern plays. Is it safe?
A: It is a reconstruction of half of the arena, rather solid and safe. There have already been plays, but very serious ones (a Greek tragedy in Persian!!!), apart from Paul McCartney’s little concert inside (2-300 people). I told you about the “sacred” attitude. And there is still the halo of the legend of Christian martyrs. Remember that the Pope has revamped the ancient tradition of the Via Crucis (a religious ceremony about the Death of Christ) just outside the Colosseum, so there is the danger of appearing sacrilegious.
Q: Will the Colosseum’s basement ruins be able to hold the loads?
A: Noooo problem. The basement is not in ruins. Look at the page on foundations.
I posted interview questions on discussion board groups.yahoo.com/group/talkinaboutarchitecture for additional primary sources. A grad student at UC Berkeley Mark (marq78) answered a few of the questions. Because he is taking a class on Roman Colosseum, his answers are considered trustworthy.
Q: Some sources state, that there were the slavery was
used to build the Colosseum, other sources, however, state that the amphitheatre is too perfect and it was built by the experts. Which theory do you support and why?
A: The Colosseum was most definitely built with slave labor, as all Roman Buildings were. There is no other way they could have finished a building this large in such a short amount of time (5-8 years).
Most of the labor did not have to be skilled, it was hard labor that
only required people to lift or pull ropes.
Q: During my research I found that the reason the Colosseum is structurally strong and still remains is the different materials used such as tufa, travertine, brick, and cement. How do all these different materials work together? Isn’t it important to take into account the different expansion factors, resistance, etc., of the different materials while designing the building?
A: They are used based on how much of a load they can support.
Travertine is at the lower levels, as it can support the most and
tufs and brick are found in areas the require less loading.
Aggregate: The mineral materials, such as sand or stone, used in making concrete.Amphitheatrum: “Amphi” means round in Greek. Amphitheatre is a combination of two theatres, so it is bigger, and it is used for action games instead of the plays.
Anchored: A rigid point of support, as for securing a rope.
Awning: A roof like structure often made of canvas or plastic that serves as a shelter, as over a storefront, window, door, or deck. For the Colosseum it also was called Velarium.
Brick: Were produced with clay mixed with water and often with sand, straw and finely ground pozzolana.
Cavea: The sloping floor and the seating area (almost the entire space in the interior of the superstructure: above the subterranean area and besides the arena).
Clipea: A series of decorative bronze shields around the top stories of the Colosseum that were added by Domitian.
Concrete: A hard, strong construction material consisting of sand, conglomerate gravel, pebbles, broken stone, or slag in a mortar or cement matrix.
Consoles: An often scroll-shaped bracket used for decoration or for supporting a projecting member, such as a cornice or shelf.
Corinthian: The most ornate of the three main orders of classical Greek architecture, characterized by a slender fluted column having an ornate bell-shaped capital decorated with acanthus leaves.
Cornice: The molding at the top of the walls of a room, between the walls and ceiling.
Domitian: Second Vespasian’s son who was in power of Roman Empire from 81 A.D. to 96 A.D.
Domus Aurea: Emperor Nero established his palace called Domus Aurea (Golden Palace) by the lake, at the present location of the Colosseum.
Doric: The oldest and simplest of the three main orders of classical Roman architecture, characterized by heavy fluted columns with plain, saucer-shaped capitals and base.
Excess soil: All the soil that was dug out during the excavation of the foundation.
Flavium (Flavian Emperors): After Nero’s death, emperor Vespasian came to the power, who started the Flavian dynasty. It was short dynasty of him, and two his sons Titus and Domitian.
Harena: It means sand in Latin, which covered the floor of the arena. From this, the word arena was derived.
Ionic: One of the three main orders of classical Greek architecture, characterized by two opposed volutes in the capital.
Limestone: A common sedimentary rock consisting mostly of calcium carbonate, CaCO3, used as a building stone and in the manufacture of lime, carbon dioxide, and cement.
Maenianum primum: A sitting space in the Colosseum above the first rows on the podium, which was dedicated to wealthy citizens and aristocrats.
Maenianum secundum imum: A sitting space in the Colosseum at the lower (second) tier for middle-class citizens.
Maenianum secundum summum: A sitting space in the Colosseum at the higher (third) tier for poor citizens.
Maenianum summum in ligneis: A sitting space in the Colosseum at the highest story. It was standing room only and very poor citizens and women were assigned to these seats.
Mayor of Rome: Walter Veltroni
Mortar: Any of various bonding materials used in masonry, surfacing, and plastering, especially a plastic mixture of cement or lime, sand, and water that hardens in place and is used to bind together bricks or stones.
Munera: A combat between two gladiators. The emperor decides weather gladiator that looses the fight lives or dies.
Naumachiae: Naval battles held in the Colosseum during the first year after its dedication. Mostly, it was and imitation of some actual sea battle that Romans have won.
Nero: An emperor, who ruled the Rome before Vespasian. He had built an enormous mansion right in the center of Rome, were the Colosseum now is located.
Pavement: A hard smooth surface, especially of a public area or thoroughfare that will bear travel.
Peperino: A stone that formed from a mixture of volcanic ash, gravel and sand, harder than tufa and more fireproof.
Pivot: A short rod or shaft on which a related part rotates or swings.
Podium: a 4.5 m (15 ft) high wall around the arena. The first few rows of seats also are called podium.
Pozzolana: A siliceous volcanic ash used to produce hydraulic cement.
Vault: An arched structure, usually of masonry or concrete, serving to cover a space.
Renaissance: The humanistic revival of classical art, architecture, literature, and learning that originated in Italy in the 14th and lasted through 16th century, which spread throughout Europe.
Cement: A building material with a binding agent usually produced by mixing finely ground limestone and clay.
Settlement: An action, when a building is sinking in to the soil until it adjusts to it. It is measured in millimeters or fractions of inches.
Socket: An opening or a cavity into which an inserted part is designed to fit.
Stucco: A durable finish for exterior walls, usually composed of cement, sand, and lime, and applied while wet.
Substructure: The supporting part of a structure; the foundation or basement.
Subterranean area: A space under the in the basement of the Colosseum, which contained all the necessary equipment and decorations for games. Gladiators and animal were placed in the rooms and cages there before the game.
Superstructure: The part of a building or other structure above the foundation.
Titus: Vespasian’s son, who took Rome over after his father’s death. He finished the Colosseum by adding third and fourth stories and dedicated it in 80 A.D.
Travertine: A sedimentary stone made essentially of calcite, deposited by calcareous waters. The stone can stand a pressure of 226/298 Kg/cmq, depending on its quality.
Tropicana Casino: On October 31, 2003 a 5-story garage belonging to Tropicana casino in NJ collapsed during the construction. The reason of the disaster was a failure of the concrete, which cased a death of tree construction workers.
Tufa: A rock composed of compacted volcanic ash varying in size from fine sand to coarse gravel.
Unknown architect: Architect of the Colosseum is unknown. It is believed, though, that building was assigned to four different contractors for each quadrant of an amphitheatre.
Velarium: Awnings that were supported by wooden beams at the top of the Colosseum. It was a scarlet, blue, and yellow colored, with a hole in the middle to provide air circulation. Sailors maneuvered Velarium.
Venationes: An imitation of the wild animal hunts in the arena of the Colosseum.
Vespasian: After Nero’s suicide in 68 A.D., Vespasian came to the power and started a new Flavian dynasty. He started the Colosseum in order to regain a favor of the Romans.
Waist materials: After a big fire in the city of Rome, a lot of houses built by the lake in Nero’s gardens burned down. All the debris was used to lift the site of the Colosseum and deepen the foundation.
WSW-ESE: Longer axis if the amphitheatre was oriented West-South-West and East-South-East.
WW2: A war fought from 1939 to 1945, in which Great Britain, France, the Soviet Union, the United States, China, and other allies defeated Germany, Italy, and Japan.