Download The Milvian Bridge in Rome

CONTENTS
 Vitruvian Architecture
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Key Elements of Roman Architecture
o Columns
o Arches
o Building Materials
Infrastructure
Roads
o Roadworks
o Via Appia
o Via Flamina
o Via Sacra
Bridges
o Milvian Bridge, Rome
o Bridge over the Tagus river at Alacantra, Spain
Aqueducts & Sewers
o Punic quanats
o Cloaca Maxima, Rome, Italy
o Hadrian’s Aqueduct, Carthage, Tunisia
o Aqueduct at Segovia, Spain
o Pont du Gard, Nimes, France
Public Buildings
Temples
o Greek Temple orders and styles
o The Tuscan temple
Rectangular Temples
o Temples of Rome & Augustus at Lepcis Magna, The Capitolium of Rome & Thuburbo Majus,
Tunisia
o Maison Caree, Nimes, France
o Temple of Bacchus at Baalbek, Lebanon
 Exterior
 Interior
Round Temples
o Temple of Venus at Baalbek, Lebanon,
o Temples of Vesta in Tivoli and Rome, Italy
o The Pantheon, Rome
 Exterior
 Interior
Basilicas
o Greek influences: the basiliké stoa
o Vitruvian utilitarian model: Basilica at Cosa, Etruria
o Pompeian Model: Pompeian basilica
o Basilica Nova Maxentius
Baths
o A day at the thermae
o Stabian Baths, Pompeii
o Hadrianic Baths, Lepcis Magna
o Baths of Caracalla, Rome
o Baths of Diocletian, Rome
o Hunting Baths, Lepcis Magna
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Circuses
o What is a circus?
o Circus Maximus, Rome
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Theatres
o Greek influences
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The Roman theatre
Theatre at Timgad
Theatre at Lepcis Magna
Theatre at Aspendos
Theatre at Sabratha
Theatre at Orange
Reconstruction of the theatre of Marcellus, Rome
Amphitheatres
o Gladiators
o Amphitheatre at Pompeii
o Amphitheatre at Nimes
o The Flavian Amphitheatre, Rome
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Vitruvian architecture
Vitruvius was a Roman architect active in the late 1st century BC. He was heavily influenced by Greek geometry
and philosophy particularly Pythagorean aesthetics (the philosophy of Beauty) and was especially interested in
the ratio of proportionality known as the Golden Mean and signified today by the Greek letter (phi).
According to Vitruvius, buildings should mimic nature, which in turn mimics the ideal forms of mathematics.
Vitruvius studied Pythaorean philosophy and found that geometry abounds in all natural things from inanimate
rocks to the humming hives of bees. He wrote a series of treatises entitled De Architectura (On Architecture) in
which he said that architecture should resemble life and to this end he described the ideal proportions of a man.
Leonardo Da Vinci famously sketched this Vitruvian Man and showed how he fitted perfectly into a square and
an equilateral triangle according to the dictates of the Golden Mean.
Vitrvius also outlined 3 principals upon which buildings, to his way of thinking, should be built.
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firmitas – it must be built of strong and durable material
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utilitas – it must be functional and usable
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venustas – it must be beautiful.
This last one is very complicated. Simply put it must look beautiful but beyond boasting exquisite
decoration it must conform to the mathematical laws of proportionality
If all these principals are adhered to, then the resultant building will, through its proportional symmetry,
convey a sense of eurythmia: an intrinsic harmonous beauty.
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The arch was known to the Egyptians and the Greeks but never used to its potential until Roman times. The
Greeks favoured the post and pillar format of the temples for their public buildings but this limited them in
terms of space they could leave in a building. They made fine use of triangular roofs however but again the
structures suffered from great stresses and strains, which limited the Greeks to using very strong, hard and
expensive marble. The arch could be constructed with anything from cheap brick to polished marble and
allowed the Romans to play with space.
Roman arches were constructed from unmortared (no cement) voussoirs (wedge shaped blocks) which were
held in position by a central keystone and set upon flat slabs called imposts.
Thrust is the term given to the downward and outward force exerted by the combined mass of the blocks of a
structure.
In many arched buildings, strong thick supporting walls known as buttresses has to be built. These stopped the
arch from collapsing due to the thrust of its load.
When several concentric arches are combined and juxtaposed they formed a tunnel known as a barrel-vault. When
two barrel-vaults intersected at right angles they formed a cross-vault and an arch constructed in three dimensions
forms a dome.
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Building materials
Stone
Tufa
Travertine
Pentelic Marble
Porphyry
Alabaster
Tufa is an igneous rock like pumice, which ranges in its strength and hardness. It is distinctive due its pockmarked appearance; caused by trapped air bubbles in the cooling lava.
Travertine is a sedimentary limestone (sometimes mistakenly identified as marble) that comes from a large
quarry in Tivoli near Rome. It is typically pock marked and porous and can be polished to a fine finish. The
Colosseum is constructed almost entirely from travertine. Its actual name in Latin was lapis tiburtinus - stone
from Tibur (ancient Tivoli). It comes in a variety of colours ranging from light brown to mottled red.
Pentelic marble is a fine white marble imported from the Athenian quarry in Greece. A similar Italian
marble was quarried at Luna.
Porphyry was a highly prized redish-purple granite that was imported from Egypt at huge expense.
Alabaster (sometimes known as gypsum) is a soft whitish chalk quarried in Tuscany, north of Rome. It was
used for carving decorations. When heated in boiling water it acquires a translucent quality resembling true
marble. Albaster is properly a natural mineral compound rather than an actual rock.
Compounds
Stucco is a durable cement-like plaster made simply from lime, sand, marble dust and water. It was used in
varying consistencies (ratios of contents to water) as a dressing for exteriors and interiors alike.
Concrete is a compound material made by mixing cement (lime, sand and water) with an aggregate: usually gravel or
shingle. It was originally discovered by the Egyptians but they failed to realise its potential. In the 1 st century BC
however the Romans became masters in the uses of concrete. Concrete suffers from thrust and often cracks along
faults in walls. This is due to the fact that concrete is porous and so it swells and shrinks depending upon its water
content. The Romans however discovered that when mixed with pozzolanic ash (a volcanic ash of varying colours
found around Mt. Vesuvius near Naples) at a ratio of 2:1 with lime before being added to the mixture of sand,
aggregate and water the resultant concrete was slow drying, water proof once dry and very hard wearing. Roman
water channels and sewers were coated in this type of concrete and sections of the original aqueduct in Rome are still
in use today. The Roman harbour at Cosa in Tuscany was built with Roman concrete and also remains in use today.
Concrete was often faced with slabs of marble to make the walls look more appealing but the Romans were very fond
of building walls with concrete because it was so strong, moldable and cheap.
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Roman Roads
Although there is now archaeological evidence in France and Ireland that contradicts
the saying that All roads lead to Rome, one cannot compare the crude timber
causeways of the Celts to the geometrically surveyed, well built and beautifully
flagged Roman roads. Wherever they went the Legions of Rome brought their roads
with them creating a vast infrastructural network leading back to the Forum from
whence they came.
Roman legions supplemented by slave labour built the roads. Surveyors using a basic
knowledge of trigonometry and a simple cross-staff of plumb lines known as a groma first
plotted the line of the road. The Romans preferred straight roads with precious few turns. The
surveyors would deliberately off-set the line of the road gradually to avoid having to put a
noticeable bend in it and where possible they would even cut through hills rather than go over
them. Mountains were unavoidable but the straightness of Roman roads is a testament to the
engineers’ commitment to the right angle and evidence of the technology they used to build
their roads.
3 Famous Roads of Rome
Via Sacra
 The oldest and consequently most sacred street of Rome.
 It begins on the Capitoline Hill, passed through the Forum Romanum and ended at the
site where the Colosseum stands today.
 It passed some of the most sacred sites in Rome (hence the name) and formed part of the
Via Triumphalis – a route rather than a road used by victorious consuls during Republican
times and later by Emperors on their triumphal parades.
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Via Flamina – most important road to the north.
 Built by Gaius Flaminus (censor) 220BC.
 Length: 311km
 It begins just inside the northern gate of Rome in the Aurellian walls at Porta Flaminia
(now Piazza del Popolo – the square of the poplars) and ends in the ancient city of
Ariminum (Rimini) on the Adriatic.
 Under Vespasian in AD69 the tunnel through the mountain at Furlo was enlarged. It is
still used today along the modern highway known as the SS 3 Flaminia.
Via Appia “the queen of the long roads (Statius)” and main road to the south.
 Length: 200km south from Rome to Capua – the original road.
 Built by Appius Claudius Caecus (censor) 312BC.
 It was the first long road built specifically for troops to march to and from Rome.
 It crossed the Pontine Marshes to the south which had up until that point formed a
geographic obstacle (and a high risk of malaria) to the Romans in their skirmishes with
the nearby Oscan tribes.
 71BC 6000 defeated slaves of Spartacus’ slave revolt were crucified along the Via Appia
between Rome and Capua.
 It was extended several times afterwards by a further 375km and finally by Emperor
Trajan in the 1st century AD to Barium (modern Bari) and Brundisium (Brindisi); ports on
the heel of Italy.
All road distances were calculated from the same starting point: the so-called Golden
Milestone: a rock coated in gold-leaf that stood in the Roman Forum. It was said to be the
heart of Rome. If all roads led to Rome, they led to the Milliarium Aurium (Golden
Milestone).
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Bridges
A bridge is a continuation of a road where no road can be built. Roman bridges are a
testament to Roman stone masonry as much as they are to the use of the arch. Roman bridges
were constructed with unmortared masonry (no cement). Dry rectangular stone blocks were
put together in stretcher and header courses: one layer of blocks was laid lengthwise, whilst
the next was laid perpendicular. The blocks were then dovetailed together (held by pressure
caused by small wedge shaped blocks hammered between them) or else held together by
means of metal pins. And in true Virtruvian style bridges often featured graded arches, the
largest being at the centre and grading down in size symmetrically to the sides.
The Milvian Bridge in Rome
Wheeler, p.152, il.135
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Built by Consul Marcus Aemillius Scaurus in 109BC to replace the original wooden
bridge built by Consul Gaius Claudius Nero (not the famous Emperor Nero) in 206BC.
Built primarily of unmortared tufa but faced with travertine
Bridge is slightly hump-backed but the hump is located between the 3rd and 4th arches to
meet the slightly higher bank on one side.
Two barrel-vaults flank the 4th arch forming flood-passages to relieve the bridge when the
Tiber is in flood.
Similarly the imposts (feet of the piers) are wedge shaped on the up-river side. These act
as breakwaters that direct the force of water through the arches and off of the piers.
The viaduct on top is 8m wide and enclosed by two parapet walls on either side.
6 arches. The widest spanning almost 60ft/18.55m
The bridge carried the Via Flaminia across the Tiber. It would have been used as a main
thoroughfare for the movement of people and goods.
Incidentally
It was the scene of a famous battle (The Battle of the Milvian Bridge) during the civil war
between Emperors Constantine I and Maxentius in AD312; a battle in which Constantine
was victorious.
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The bridge across the Tagus valley at Alacantara in Spain
Wheeler, p.153, il.136
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Located at the city of Alacantara near the border between Spain and Portugal.
Built of unmortared granite
There is a dedication to Trajan on the triumphal arch at the centre
IMPeratori. CAESARI DIVI NERVA Filio. NERVAE
TRAIANO AVGVSTO GERMANICO DACICO PONTIFici. MAXimo. This is the
official title of Trajan as Emperor. The inclusion of Dacico means that the inscription was
carved after Trajan’s triumph on return from Dacia (AD102).
Bridge built by AD106
The piers are buttressed to withstand the thrust of the arches and held together by
means of metal clamps to withstand the pull of the river. The up-river sides are
rounded so as to act as breakwaters, which direct the flow of water through the arches
and stop the water from exerting full pressure on the piers themselves.
The widest arches at the centre measure 94ft/28.8m
The length of the bridge is almost 200m (194m).
The viaduct is 8m wide
At the highest point, the bridge is more than 50m above the river.
6 arches in total hold up the viaduct linking the two sides of the Tagus ravine.
There is a little Roman temple on the city side, bearing a dedication to the bridge
builder: Gaius Julius Lacer.
Incidentally
The bridge was damaged several times in the medieval period by the Moors, Spanish and
the Portuguese. Less than masterful repairs were made using cement, which serves to
prove the mastery of the Roman stone masons.
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Waterworks: Aqueducts & Sewers
Past influences and precedents
The Greeks
Polycrates of Samos (a Greek island) famously cut a water channel that stretched some
1,100ft long linking a water source with the city. It was in essence an aqueduct as it was
covered. It was however crudely constructed, being simply hewn through the rock.
Persians & Etruscans
The Persians had used qanats to irrigate the arid landscape of Iran long before Rome was
even founded. The Phoenicians acquired this technology and it quickly spread throughout the
various Punic colonies scattered throughout the Mediterranean, including Etruria
(Tuscany).The Romans therefore perfected an earlier Etruscan method of irrigation and
drainage.
A qanat – which is a Persian word – was a purpose built underground water channel that
sloped very gradually downward from higher ground, from an aquifer - a subterranean water
rich layer of permeable rock. This was tapped. Vertical shafts were then dropped at regular
intervals along the channel from which water could be drawn. The channel would eventually
come out into the open in the foothills where it would become a canal that would irrigate the
surrounding landscape.
Illustration not in Wheeler
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Aqueducts
illustration not in Wheeler
Aqueducts were purpose built Roman water channels in which the gentle flow of water was
carried by the force of gravity. The ducts themselves (like the one pictured above) were lined
with fine concrete mixed with pozzolanic ash. This formed a waterproof seal that prevented
leakage. The duct was then covered with stone slabs to protect the water from animal and
fecal contamination. The duct was then buried underground.
What we refer to as an aqueduct today is usually only a tiny portion of the original aqueduct.
Of all the aqueducts in Rome, only 10% are visible above ground. The aqueduct bridges,
which we mistakenly call aqueducts, were brought into use to carry aqueducts across
irregular terrain like valleys and ravines.
The aqueduct bridges that survive are as much a testament to Roman surveying as they are to
engineering and architecture. The line and levels of aqueducts had to be exact. Aqueducts do
not tolerate many twists and turns. The flow of water has to be gentle and very slight (think
how violently water behaves when swirled in a glass) so the straighter and more gradual the
gradient the less likely the water is to erode the channel from the inside. For example, the
Pont du Gard outside Nimes in France drops only 34cm per kilometre and drops only 17m
vertically in its entire length of 51km.
Vitruvius was the first to describe how water finds its own level and therefore aqueducts work
by the power of gravity. He went on to describe in great mathematical detail the problems
facing any aqueduct. The fragility of the watercourse was the main one. The flow of water
had to be gentle to prevent erosion of the channel and blow outs and despite the precision of
Roman engineering, aqueducts had to be constantly maintained so as to guard the purity of
the water, which they carried.
Incidentally
In AD95 Emperor Nerva appointed Frontinus, one of his generals, to the position of curator
aquarum charged with carrying out a full survey of all 11 aqueducts that served Rome. At the
end of the first century he published “De Aquaeducto”, which counts as the first published
survey of public works. Thanks in part to Vetruvius’ original calculations he was able to
detect discrepancies between the in-take and out-fall volumes and to uncover illegal tapping
of the aqueducts by individuals and local industries.
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Single Tiered Aqueduct of Hadrian in Carthage
Wheeler, p.150, il.133
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Built AD131
Original length 90km/55 miles from Zaghoun mountains to Carthage, modern Tunis.
Built primarily of local sandstone and reinforced with brick
Double Tiered Aqueduct of Segovia in Spain
Wheeler, p.151, il.134
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Wheeler says it was built c.AD10 but recent research suggests that it was probably later:
between the late 1st and early 2nd centuries AD during the reigns of Emperors Vespasian
or Nerva.
Built of unmortared granite blocks
36 arches on each tier
The upper arches are smaller but wider: 5.1m/16.1ft.
The lower arches are taller but narrower: 4.5m/14.8ft
Combined height including the water channel is 34m at the centre
The total length of the aqueduct bridge is approximately 900m
Simple moulded imposts break the monotony of the piers: 2 on each pier of the upper
level and 4 on most piers of the lower level except towards the sides where it is the lower
piers that grade away gradually.
At the top the water channel is lined with concrete and which forms a U shaped duct
0.55 by 0.46 meters (1.8 by 1.5 feet) and was once covered with granite slabs.
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Three Tiered “Pont Du Gard” in Nimes, France
Wheeler, p.150-51, il.132
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Built c.AD14
Total length of aqueduct was 50km/31miles from Fontaines d’Eure near the modern town
of Uzes to the Roman city of Nemausus (Nimes).
Total length of aqueduct bridge at highest level: 275m across the small Gardon river
Combined height of all the tiers was 49m/180ft above the river
Lower tier: 6 arches, 142 m long, 6 m thick, 22 m high
Middle tier: 11 arches, 242 m long, 4 m thick, 20 m high
Upper tier: 35 arches, 275 m long, 3 m thick, 7 m high
Water channel: 1.8m/(6ft) high, 1.2m/(4ft) wide and has a gradient of 0.4%
The whole aqueduct delivered 6 million gallons of water daily to Nemausus
Breakwaters and wide span of 6 lowest tiers eliminate water erosion from river
Moulded imposts break the monotony: 2 on uppermost tier of piers & 3 on the middle.
The aqueduct bridge doubles as a viaduct on the first level, though the modern road is
actually a newer bridge built in the 18th century to safeguard the Roman aqueduct.
Some of the granite blocks weigh as much as 6 tons bear the original Roman mason
marks indicating their exact place and number right or left.
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Cloaca Maxima (Great Sewer) of Rome
Wheeler, p.148, il.131
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Built by the Etruscan kings prior to the foundation of the Republic by Tarquinius
Priscius c.600BC.
It was originally fed by three streams from the hills around the forum and was for the
most part an open drain, though certainly some of the lower parts must have been
tunneled below ground.
The technology is basically a reverse qanat. Instead of drawing water from the main
channel, waste was added through drains.
In 33BC Marcus Agrippa an accomplished general and then an elected aedile
(responsible for public works) as well as a close personal friend of Caesar Augustus
carried out extensive and badly needed maintenance of the sewers. He perfected the
Etruscan drains and turned them into a fully functional city sewage network. The
barrel vaulted tunnels were probably added at this time.
There were six other sewers in Rome that ran into the Cloaca Maxima just before it
reached the outfall into the Tiber (pictured above) near the ancient bridge nicknamed the
Ponte Rotto (broken bridge). Actually the outfall is to the left of the modern Ponte
Palatino as one crosses the Tiber from the Forum Boarium to Trastevere. The Ponte
Rotto is on the right.
By the 1st century AD the 11 aqueducts that supplied Rome with fresh water
ultimately ended in the Cloaca Maxima so the water pressure in the sewer was kept
constant. This flushed out blockages.
The sewer had its own goddess, Cloacina – an aspect of Venus. A shrine to Venus
Cloacina was erected in the Forum Romanum directly over a drain to the sewer. Janus
was also somehow connected to the sewer, as Constantine I erected an arch to Janus
Quadrifrons (4 headed Janus) again over a drain to the Cloaca in the Forum Boarium (the
cattle market). The specific meanings of these cults have been lost over time but the
Romans must have felt that these deities were as important as their sewers; else they
would not have built shrines to them.
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