FREE ESSAY ON PANTHEON

PANTHEON

Introduction I chose to report on the pantheon because I've seen pictures and I am also
very fascinated by all the Roman monuments. I looked all around the internet and
libraries. The Pantheon was very hard to find information about. It was very challenging
but I found enough information to complete this report. This famous building stands in
the business district of Romemuch as it was built some 18 centuries ago. Amazingly, it
has withstood the ravages of both the elements and war permitting a firsthand view of a
unique product constructed by Roman hands. Now, it is exposed to acid rain and fumes from
passing automobiles and overshadowed by buildings of inferior taste; but, with trust in
the future, the Pantheon will survive. Unrecognized, the design of this ancient concrete
building reveals unparalleled features not encountered in modern design standards. Recent
studies reveal several major cracks in the dome, but it still functions unimpaired. This
condition will surely excite the curiosity of our structural engineers. The building was
built entirely without steel reinforcing rods to resist tensile cracking, so necessary in
concrete members, and for this concrete dome with a long span to last centuries is
incredible. Today, no engineer would dare build this structure without steel rods! Modern
codes of engineering practice would not permit such mischief. No investor with knowledge
of concrete design would provide the funding. Additional constraints when attempting to
build a structure as large as the Pantheon will be discussed later, but briefly they
include the use of inadequate hand tools and unsafe lifting devices. I believe we can
learn from this activity. Workers can build from a plan and can successfully use their
proven practices only if construction quality controls are maintained. History tells us
that the Pantheon is a Greek word meaning to honor all Gods (particularly the Olympian
divinities). It is ironic that our building has existed throughout many wars while being
dedicated to all Gods; one can readily perceive this to be a temple for our one God. And,
the Church has claimed this holy structure as a resting place for its most famous Popes,
so we continue to honor its magnificent divinity. The first incarnation of this ancient
temple was built by Agrippa, the son-in-law of the Roman Emperor Augustus, about 27 B.C.
Today, above the entrance carved in stone are the words M. AGRIPPA L. F. COS. TERTIUM
FECIT which is translated, Marcus Agrippa, son of Lucius, in his third consulate, made
it. Indeed, it is worth mentioning that Agrippa's engineering talents were used in
building the famous Pont de Gard aqueduct in France. As with many cities, tragedy in the
form of large fires such as those of 60, 64, 79, 100 and 110 A.D. seemed to strike Rome.
Originally, many Roman buildings contained travertine (limestone rock) which easily
cracked in fires. The first Pantheon was severely damaged and required replacement except
for some parts of the lower porch section and foundation. The Pantheon was rebuilt by the
Emperor Hadrian during the period 118 to 128 A.D. (a time given by Ward-Perkins).2 But
the Ward-Perkins's period is disputed by, Lugli who said the building was started
sometime after 123 A.D. and was finished by Emperor Pius about 140 A.D.3 However, most of
the bricks were made and placed in the Pantheon in 123 A.D., a date that the maker
stamped on his bricks. This was discovered in 1892 by the French archaeologist, George
Chedanne. It appears the construction of the rotunda walls took a period of 4 to 5 years,
and the dome required a like period because of its height and the meager tools the Romans
used. This long construction period was fortunate as it gave this pozzolan concrete ample
time to cure and gain strength. Was the second temple like the first? Yes, the
fundamental principle of the old Roman religion required that the temples be rebuilt
without changes in original form. Tradition required that the main entrance face north,
and thus the whole building was oriented on the north-south axis of the building. A
description of its structural features is separated into the configuration, foundation
ring, circular walls, and dome to more clearly define various components. How these
pieces are unique in view of today's design requirements will be discussed shortly. Body
The Pantheon is one of the great spiritual buildings of the world. It was built as a
Roman temple and later consecrated as a Catholic Church. Its monumental porch originally
faced a rectangular colonnaded temple courtyard and now enfronts the smaller Piazza della
Rotonda. Through great bronze doors, one enters one great circular room. The interior
volume is a cylinder above which rises the hemispherical dome. Opposite the door is a
recessed semicircular apse, and on each side re three additional recesses, alternately
rectangular and semicircular, separated from the space under the dome by paired
monolithic columns. The only natural light enters through an unglazed oculus at the
center of the dome and through the bronze doors to the portico. As the sun moves,
striking patterns of light illuminate the walls and floors of porphyry, granite and
yellow marbles. Inside the Pantheon The building design is one of a large round shape
very much like a large barrel with a dome covering the top. There is a light-well in the
center of the dome. Layers of beautiful thin brickwork cover the outside, round walls.
Small access holes appear occasionally in the wall which were used during construction to
frame interior voids. The main entrance is thoroughly impressive: double bronze doors 21
feet high (6.4 meters), a lasting and fitting contribution from their metal smiths. These
doors are protected by a high, broad porch, made with 16 well arranged granite columns
supporting a gable styled roof. The beams in the roof structure of the porch are wooden.
They were substituted for bronze members stripped-out by those in later years needing
metal for their canons. Professional Roman surveyors located the inlaid marble floor to
conform with a convex contour which drained away the rain from the oculus for these
hundreds of years. In the following descriptions, some general dimensions are given to
indicate the magnitude of this undertaking by the Romans. The rotunda has a rather
awesome inner diameter of 142.4 feet (43.4 m), made mostly of concrete. Comparatively
speaking, this distance represents about one half the length of our football field. And
from the floor to the top of the opening in the dome is the same distance. As a matter of
fact, we could think of the design of this building as one that could contain a
theoretical ball some 143 feet in diameter. The design is not entirely unusual because
there are other Roman buildings which have a similar configuration, but the size is
unusual. Other buildings such as the Temple of Mercury (71 feet/21.5 m diameter) at Baiae
and Domitian Nympheaum at Albano (51 feet/15.6 m diameter) have domes of this type. The
Pantheon still has the longest span constructed before the 19th Century. To provide
details on this complex configuration, the following figures show the building with its
two-ring foundation, voids in the walls, and the step-ring and coffer arrangement in the
dome. Foundation The Pantheon was built on marshy, unstable earth which gave a serious
supporting problem to its builders. The Jutland Archaeological Society described in
detail various aspects of the ring foundation; they found it rested on a bed of bluish
colored river clay.8 This condition invited disaster, and in the final construction
phase, the foundation cracked at the two ends of the North-South axis. If one section of
a building settles slightly faster and lower than an adjacent section, very large bending
stresses are initiated at a point between these two sections which can crack the
concrete. And uneven settling was the problem given to the builders. The present-day
engineering solution to this type of foundation problem is to drive piles through the
clay to bedrock so the building will be firmly supported all the way around. The Roman
builders chose a different approach. They built a second ring to hold the first ring from
cracking further and to give the clay more area to support the structure. It worked
because the building has lasted over 1800 years. In addition to keeping the crack from
extending, the builders placed buttress walls on the south side opposite the massive
porch. This acted as a clampng device; and although the structural projection appears to
be an additional room, it only serves the purpose of being part of the clamp. These rings
are made of pozzolan concrete consisting of travertine pieces in layers held together by
a mortar of lime and pozzolan. This will be discussed later in this work. Interestingly
enough, the Jutland Society's investigation showed the foundation material had become
rock hard,11 a case we might expect when we study the chemistry of pozzolanic reaction
under these conditions. How It Stands up The challenge of determining stresses within
various sections of the Pantheon has always excited both architects and engineers who are
interested in the building. Technical design people recognized that the long 143 foot
span of the ancient dome could have critical stress concentrations leading to a
catastrophic failure of the structure, but this has not happened. Nothing in life seems
perfect, and this is the case with the Pantheon. The dome and walls have cracked.
Concrete cracks under excessive tensile stress as viewed in a hoop condition. A.
Terenzio, an Italian superintendent of monuments, documented cracking in the walls and
dome duringhis inspection of the Pantheon in 1930. Terenzio identifies fractures
`reaching from the base of the rotunda to the summit of the dome' that he thought were
brought about by differential settlement from uneven loading of the wall, particularly
near the entrance of the rotunda in the principal niche. Rather than finding vertical
differential settlement, we have observed only traces of lateral opening across the
cracks corresponding to the effect of hoop tension. Terenzio believed cracking occurred
shortly after construction because of dated brick repairs. The Mark and Hutchinson study
showed that meridional cracking in the dome was in the lower half extending up to about
57 degrees from the horizontal on the spring line. An earlier stress analysis of this
dome by Cowan theoretically placed this point at 37 degrees 36'. This is the point where
hoop stresses in the dome change from tension to compression presenting a point of
weakness within the unreinforced concrete dome. This theoretical point is in reasonable
agreement with the actual end of meridional cracking. The Mark and Hutchinson study
located the cracks as occurring generally at the openings within the upper cylindrical
wall which increased local tensile hoop stresses. In addition to dome, Terenzio mentioned
that cracks in the walls extended upward from 24.6 feet (7.5 m) above the floor. The
cracking pattern of the concrete in the Pantheon provides an unique stress configuration
acting in the dome and walls. Mark and Hutchinson describe this picture as one in which
the major internal forces in the cracked dome are only in the meridional direction, and
this region serves as a series of arches which bears a common compression keystone in the
form of the uncracked upper dome. The cracked walls serve as a series of independent
piers to support these arches. Perhaps as insurance against som future dislocation,
should we add a steel band around a step-ring? Although the building has survived
centuries, this valuable, cracked landmark of Roman history should be protected against
future earthquakes at a small cost. Conclusion As you can tell the Pantheon was a great
structure created by the Romans. I believe it has played a great role in Greek history.
Even though this building is unpopular to many people, but this report proves that it is
one of the greatest and most historical man made creation. Bibliography Encarta 95
Encyclopedia H. W. Cowan, The Master Builders. John Wiley and Son, New York, 1977
Http://www.broyan/sor/index.pa-pr/Pantheon.html- Programmer: Jack M. Loudel 
Bibliography
Introduction I chose to report on the pantheon because I've seen pictures and I am also
very fascinated by all the Roman monuments. I looked all around the internet and
libraries. The Pantheon was very hard to find information about. It was very challenging
but I found enough information to complete this report. This famous building stands in
the business district of Romemuch as it was built some 18 centuries ago. Amazingly, it
has withstood the ravages of both the elements and war permitting a firsthand view of a
unique product constructed by Roman hands. Now, it is exposed to acid rain and fumes from
passing automobiles and overshadowed by buildings of inferior taste; but, with trust in
the future, the Pantheon will survive. Unrecognized, the design of this ancient concrete
building reveals unparalleled features not encountered in modern design standards. Recent
studies reveal several major cracks in the dome, but it still functions unimpaired. This
condition will surely excite the curiosity of our structural engineers. The building was
built entirely without steel reinforcing rods to resist tensile cracking, so necessary in
concrete members, and for this concrete dome with a long span to last centuries is
incredible. Today, no engineer would dare build this structure without steel rods! Modern
codes of engineering practice would not permit such mischief. No investor with knowledge
of concrete design would provide the funding. Additional constraints when attempting to
build a structure as large as the Pantheon will be discussed later, but briefly they
include the use of inadequate hand tools and unsafe lifting devices. I believe we can
learn from this activity. Workers can build from a plan and can successfully use their
proven practices only if construction quality controls are maintained. History tells us
that the Pantheon is a Greek word meaning to honor all Gods (particularly the Olympian
divinities). It is ironic that our building has existed throughout many wars while being
dedicated to all Gods; one can readily perceive this to be a temple for our one God. And,
the Church has claimed this holy structure as a resting place for its most famous Popes,
so we continue to honor its magnificent divinity. The first incarnation of this ancient
temple was built by Agrippa, the son-in-law of the Roman Emperor Augustus, about 27 B.C.
Today, above the entrance carved in stone are the words M. AGRIPPA L. F. COS. TERTIUM
FECIT which is translated, Marcus Agrippa, son of Lucius, in his third consulate, made
it. Indeed, it is worth mentioning that Agrippa's engineering talents were used in
building the famous Pont de Gard aqueduct in France. As with many cities, tragedy in the
form of large fires such as those of 60, 64, 79, 100 and 110 A.D. seemed to strike Rome.
Originally, many Roman buildings contained travertine (limestone rock) which easily
cracked in fires. The first Pantheon was severely damaged and required replacement except
for some parts of the lower porch section and foundation. The Pantheon was rebuilt by the
Emperor Hadrian during the period 118 to 128 A.D. (a time given by Ward-Perkins).2 But
the Ward-Perkins's period is disputed by, Lugli who said the building was started
sometime after 123 A.D. and was finished by Emperor Pius about 140 A.D.3 However, most of
the bricks were made and placed in the Pantheon in 123 A.D., a date that the maker
stamped on his bricks. This was discovered in 1892 by the French archaeologist, George
Chedanne. It appears the construction of the rotunda walls took a period of 4 to 5 years,
and the dome required a like period because of its height and the meager tools the Romans
used. This long construction period was fortunate as it gave this pozzolan concrete ample
time to cure and gain strength. Was the second temple like the first? Yes, the
fundamental principle of the old Roman religion required that the temples be rebuilt
without changes in original form. Tradition required that the main entrance face north,
and thus the whole building was oriented on the north-south axis of the building. A
description of its structural features is separated into the configuration, foundation
ring, circular walls, and dome to more clearly define various components. How these
pieces are unique in view of today's design requirements will be discussed shortly. Body
The Pantheon is one of the great spiritual buildings of the world. It was built as a
Roman temple and later consecrated as a Catholic Church. Its monumental porch originally
faced a rectangular colonnaded temple courtyard and now enfronts the smaller Piazza della
Rotonda. Through great bronze doors, one enters one great circular room. The interior
volume is a cylinder above which rises the hemispherical dome. Opposite the door is a
recessed semicircular apse, and on each side re three additional recesses, alternately
rectangular and semicircular, separated from the space under the dome by paired
monolithic columns. The only natural light enters through an unglazed oculus at the
center of the dome and through the bronze doors to the portico. As the sun moves,
striking patterns of light illuminate the walls and floors of porphyry, granite and
yellow marbles. Inside the Pantheon The building design is one of a large round shape
very much like a large barrel with a dome covering the top. There is a light-well in the
center of the dome. Layers of beautiful thin brickwork cover the outside, round walls.
Small access holes appear occasionally in the wall which were used during construction to
frame interior voids. The main entrance is thoroughly impressive: double bronze doors 21
feet high (6.4 meters), a lasting and fitting contribution from their metal smiths. These
doors are protected by a high, broad porch, made with 16 well arranged granite columns
supporting a gable styled roof. The beams in the roof structure of the porch are wooden.
They were substituted for bronze members stripped-out by those in later years needing
metal for their canons. Professional Roman surveyors located the inlaid marble floor to
conform with a convex contour which drained away the rain from the oculus for these
hundreds of years. In the following descriptions, some general dimensions are given to
indicate the magnitude of this undertaking by the Romans. The rotunda has a rather
awesome inner diameter of 142.4 feet (43.4 m), made mostly of concrete. Comparatively
speaking, this distance represents about one half the length of our football field. And
from the floor to the top of the opening in the dome is the same distance. As a matter of
fact, we could think of the design of this building as one that could contain a
theoretical ball some 143 feet in diameter. The design is not entirely unusual because
there are other Roman buildings which have a similar configuration, but the size is
unusual. Other buildings such as the Temple of Mercury (71 feet/21.5 m diameter) at Baiae
and Domitian Nympheaum at Albano (51 feet/15.6 m diameter) have domes of this type. The
Pantheon still has the longest span constructed before the 19th Century. To provide
details on this complex configuration, the following figures show the building with its
two-ring foundation, voids in the walls, and the step-ring and coffer arrangement in the
dome. Foundation The Pantheon was built on marshy, unstable earth which gave a serious
supporting problem to its builders. The Jutland Archaeological Society described in
detail various aspects of the ring foundation; they found it rested on a bed of bluish
colored river clay.8 This condition invited disaster, and in the final construction
phase, the foundation cracked at the two ends of the North-South axis. If one section of
a building settles slightly faster and lower than an adjacent section, very large bending
stresses are initiated at a point between these two sections which can crack the
concrete. And uneven settling was the problem given to the builders. The present-day
engineering solution to this type of foundation problem is to drive piles through the
clay to bedrock so the building will be firmly supported all the way around. The Roman
builders chose a different approach. They built a second ring to hold the first ring from
cracking further and to give the clay more area to support the structure. It worked
because the building has lasted over 1800 years. In addition to keeping the crack from
extending, the builders placed buttress walls on the south side opposite the massive
porch. This acted as a clampng device; and although the structural projection appears to
be an additional room, it only serves the purpose of being part of the clamp. These rings
are made of pozzolan concrete consisting of travertine pieces in layers held together by
a mortar of lime and pozzolan. This will be discussed later in this work. Interestingly
enough, the Jutland Society's investigation showed the foundation material had become
rock hard,11 a case we might expect when we study the chemistry of pozzolanic reaction
under these conditions. How It Stands up The challenge of determining stresses within
various sections of the Pantheon has always excited both architects and engineers who are
interested in the building. Technical design people recognized that the long 143 foot
span of the ancient dome could have critical stress concentrations leading to a
catastrophic failure of the structure, but this has not happened. Nothing in life seems
perfect, and this is the case with the Pantheon. The dome and walls have cracked.
Concrete cracks under excessive tensile stress as viewed in a hoop condition. A.
Terenzio, an Italian superintendent of monuments, documented cracking in the walls and
dome duringhis inspection of the Pantheon in 1930. Terenzio identifies fractures
`reaching from the base of the rotunda to the summit of the dome' that he thought were
brought about by differential settlement from uneven loading of the wall, particularly
near the entrance of the rotunda in the principal niche. Rather than finding vertical
differential settlement, we have observed only traces of lateral opening across the
cracks corresponding to the effect of hoop tension. Terenzio believed cracking occurred
shortly after construction because of dated brick repairs. The Mark and Hutchinson study
showed that meridional cracking in the dome was in the lower half extending up to about
57 degrees from the horizontal on the spring line. An earlier stress analysis of this
dome by Cowan theoretically placed this point at 37 degrees 36'. This is the point where
hoop stresses in the dome change from tension to compression presenting a point of
weakness within the unreinforced concrete dome. This theoretical point is in reasonable
agreement with the actual end of meridional cracking. The Mark and Hutchinson study
located the cracks as occurring generally at the openings within the upper cylindrical
wall which increased local tensile hoop stresses. In addition to dome, Terenzio mentioned
that cracks in the walls extended upward from 24.6 feet (7.5 m) above the floor. The
cracking pattern of the concrete in the Pantheon provides an unique stress configuration
acting in the dome and walls. Mark and Hutchinson describe this picture as one in which
the major internal forces in the cracked dome are only in the meridional direction, and
this region serves as a series of arches which bears a common compression keystone in the
form of the uncracked upper dome. The cracked walls serve as a series of independent
piers to support these arches. Perhaps as insurance against som future dislocation,
should we add a steel band around a step-ring? Although the building has survived
centuries, this valuable, cracked landmark of Roman history should be protected against
future earthquakes at a small cost. Conclusion As you can tell the Pantheon was a great
structure created by the Romans. I believe it has played a great role in Greek history.
Even though this building is unpopular to many people, but this report proves that it is
one of the greatest and most historical man made creation. Bibliography Encarta 95
Encyclopedia H. W. Cowan, The Master Builders. John Wiley and Son, New York, 1977
Http://www.broyan/sor/index.pa-pr/Pantheon.html- Programmer: Jack M. Loudel