Transcript Historic Building Survey, Inspection and Recording. Design, relief

EPOKA UNIVERSITY
Tirana, ALBANIA
2011
Faculty of Engineering and Architecture
Department of Architecture
Arch 322
Historical Environment and Conservation
Lida MIRAJ
Lesson 6
• Historic Building Survey, Inspection and
Recording. Design, relief, environment.
Diagnosis of Building Failures.
Architectural Restoration
History of Architectural Techniques. The informative
and methodological aspect, the traditional
architectural cultures, their language system and the
technique-constructive aspects. Architectural relief
and the critical reading of specific examples.
Vitruvius, writing around 25 BC in his Ten Books
on Architecture, distinguished types of aggregate
appropriate for the preparation of lime mortars.
For structural mortars, he recommended
pozzolana, which were volcanic sands from the
sandlike beds of Puteoli brownish-yellow-gray in
color near Naples and reddish-brown at Rome.
Vitruvius specifies a ratio of 1 part lime to 3 parts
pozzolana for cements used in buildings and a 1:2
ratio of lime to pulvis Puteolanus for underwater
work, essentially the same ratio mixed today for
concrete used at sea
• By the middle of the 1st century, the principles of
underwater construction in concrete were well known
to Roman builders. The City of Caesarea was the
earliest known example to have made use of
underwater Roman concrete technology on such a
large scale.
• Rebuilding Rome after the fire in 64 AD, which
destroyed large portions of the city, the new building
code by Nero consisted of largely brick-faced concrete.
This appears to have encouraged the development of
the brick and concrete industries.
In most usage, the raw concrete surface was considered unsightly and
some sort of facing was applied. Different techniques were
characteristic of different periods and included:
• Opus incertum: small irregular stones.
• Opus reticulatum: small squared tuff blocks laid in a
diamond pattern.
• Opus quadratum: regularly laid courses of ashlars.
• Opus latericium: regularly laid courses of brick.
• Opus spicatum: brick laid in a herringbone pattern.
• Opus vittatum: square tuff blocks intersected by brick
bands at regular and irregular distances.
• Opus africanum: vertical chains of upright blocks with
alternating horizontal blocks.
• Opus testaceum: thick horizontal brick work.
Roman concrete (also called Opus caementicium)
was a material used in construction during the
late Roman Republic through the whole history
of the Roman Empire. Roman concrete was
based on a hydraulic-setting cement with many
material qualities similar to modern Portland
cement. By the middle of the 1st century, the
material was used frequently as brick-faced
concrete, although variations in aggregate
allowed different arrangements of materials.
Further innovative developments in the material,
coined the Concrete Revolution, contributed to
structurally complicated forms, such as the
Pantheon dome.
Concrete, and in particular, the hydraulic mortar
responsible for its cohesion, was a type of structural
ceramic whose utility derived largely from its
rheological plasticity in the paste state. The setting
and hardening of hydraulic cements derived from
hydration of materials and the subsequent chemical
and physical interaction of these hydration products.
This differed from the setting of slaked lime mortars,
the most common cements of the pre-Roman world.
Once set, Roman concrete exhibited little plasticity,
although it retained some resistance to tensile
stresses.
The setting of pozzolanic cements has much in
common with setting of their modern counterpart,
Portland cement. The high silica composition of
Roman pozzolana cements is very close to that of
modern cement to which blast furnace slag, fly ash,
or silica fume have been added.
Italy, Rome, via Appia antica, tomb. The remains show the
internal core of the building, made in roman concrete
(cementizio: opus caementicium).
Opus Caementicium was the core of every Roman wall after
the 2nd century BC.
Mostly walls made in opus
caementicium were covered with other materials to make a
more robust and workable surface. Opus caementicium is a
construction technique using an aggregate, water and a
binding agent. The aggragate functioned as a filler like
gravel, chunks of bricks or stones and rubble. The binding
agent is usually called mortar like lime, gypsum or
pozzolana (nowadays (Portland) cement is used).
Most Roman buildings are made up of opus caementicium,
a sort of concrete which was laid into timber structures
until it hardened. The resulting walls were very solid, but
not nice to see, so very often some sort of facing was
applied.
The Romans developed a very effective kind of mortar by mixing pozzolana, a volcanic
ash of the region around Naples, with lime; they obtained a cement which was
resistant to water. In his work De Architectura (a treatise on architecture dedicated to
Emperor Augustus) Vitruvius so described pozzolana:
There is a species of sand which, naturally, possesses extraordinary qualities. It is
found about Baiæ and the territory in the neighbourhood of Mount Vesuvius; if mixed
with lime and rubble, it hardens as well under water as in ordinary buildings. This
seems to arise from the hotness of the earth under these mountains, and the
abundance of springs under their bases, which are heated either with sulphur,
bitumen, or alum, and indicate very intense fire. The inward fire and heat of the flame
which escapes and burns through the chinks, makes this earth light; the sand-stone
(tophus), therefore, which is gathered in the neighbourhood, is dry and free from
moisture. Since, then, three circumstances of a similar nature, arising from the
intensity of the fire, combine in one mixture, as soon as moisture supervenes, they
cohere and quickly harden through dampness; so that neither the waves nor the force
of the water can disunite them.
• Opus incertum was an ancient Roman
construction technique, using irregular shaped
and random placed uncut stones or fist-sized
tuff blocks inserted in a core of Opus
caementicium.
Terracina (provincia di Latina, Lazio, Italia), tempio di Giove Anxur,
fianco della terrazza su cui sorgeva il tempio, in Opus incertum.
• Opus incertum was the most common facing for ordinary
concrete walls of the 2nd and 1st centuries BC. The face of
the concrete was studded with 3- to 4-inch (8- to 10-cm)
irregularly.
• Initially it consisted of more careful placement of the
coementa (rock fragments and small stones mixed with
concrete), making the external surface as plain as possible.
Later the external surface became further plain by reducing
usage of concrete and choosing more regular small stones.
When the use of concrete between stones is particularly
reduced, it is defined opus (quasi) reticulatum.
• Used from the beginning of the 2nd century BC until the
mid-1st century BC, it was later largely superseded by Opus
reticulatum.
Opus incertum
Using irregualar shaped and random placed uncut stones or fist-sized tufa blocks inserted in a
core of opus caementicium, used from the beginning of the 2nd century BC, later superceded by
opus (quasi) reticulatum
Opus reticulatum
used on the exterior wall of Hadrian's Villa used as a retreat for the Roman Emperor
Hadrian in the early 2nd century.
Opus Reticulatum
• Opus reticulatum (also called Opus certum and known as reticulated work)
is a form of brickwork used in ancient Roman architecture. It consists of
diamond-shaped bricks of tuff which are placed around a core of opus
caementicium. The diamond-shaped tufa blocks were placed with the
pointed ends into the cement core at an angle of roughly 45 degrees, so
the square bases formed a diagonal pattern, and the pattern of mortar
lines resembled a net. Reticulatum is the Latin term for net, and opus, the
term for a work of art, thus the term literally translates to "net work".
• This construction technique was used from the beginning of the 1st
century BC, and remained very common until opus latericium, a different
form of brickwork, became more common.
• Opus reticulatum was used as a technique in the Renaissance Palazzo
Rucellai in Florence, the skill having been lost with the end of the Roman
Empire, and rediscovered by means of archeology by Leon Battista Alberti.
• The initial, rough form of opus reticulatum, an advancement from opus
incertum is called opus quasi reticulatum.
Detail of Opus Reticulatum
Opus (quasi) reticulatum
Small square tufa blocks placed diagonally to form a diamond-shaped mesh pattern,
often supllemented by other materials at frames of windows and doors or at
reinforments at corners of buildings with oblong tufa blocks
Opus Latericium and Opus Testaceum
• Opus latericium (also called opus testaceum) was a
construction technique using bricks. It was first used in the
first century BC, and it was the dominant construction
technique throughout the imperial period. Many of the
large imperial structures, such as the imperial baths of
Rome, were built in opus latericium.
• Structures in opus latericium are often easily datable,
because they are stamped by the producer. These brick
stamps were common from the first century BC until 164 AD.
At this time all the brick producing plants had passed into
imperial hands and the brick stamps disappeared, to
reappear only in the reign of Diocletian in the late
3rd century.
Opus testaceum / latericium
Brickfaced masonry - kiln-backed bricks; the dominant technique throughout the
imperial period
Ostia
Herculaneum Gate, Pompei
Baths of Caracalla
Baths of Durres
Roman Bath Durres
Prefurnium
Sewage
Opus Quadratum
• Opus quadratum is an ancient Roman construction
technique, in which squared blocks of stone of the
same height were set in parallel courses, often without
the use of mortar.
• This technique was used by the Romans from about
the 6th century BC and over time, the precision and
accuracy of the block cutting improved. The technique
continued to be used throughout the age of the Roman
Empire, even after the introduction of mortar, and was
often used in addition to other techniques. The type of
stone, the size of the blocks, and the way the blocks
were put together can all be used to help archeologists
date structures that display the technique.
Opus quadratum
Walls of cutstone, recangular in form
"Opus quadratum" at Mura Serviane (left)
and at Foro di Augusto (right).
Opus Quadratum
• Etruscan way
In early usage (often called the "Etruscan way"), the joints between
the blocks introduce discontinuities, making the blocks uneven.
Examples of such construction can be found in reservoirs,
basements, terrace walls, and temple podiums in Etruscan cities
and Rome.
• Greek way
Subsequently (the "Greek way"), the blocks would be placed in one
of two rotations. "Stretchers" would be placed so the longer side
was on the face of the wall, and "headers" would be placed so the
shorter side was on the face of the wall, and would thus extend
further back into the wall thickness. Various patterns could be
produced by changing how the blocks were placed, and it was
common to strengthen the wall by ensuring that the joints between
blocks were centered over the blocks in the row below.
The earliest walls built in Europe were constructed placing
stones one upon the other without any mortar to bind them
together (dry-stone walls). Near Rome examples of such walls
can be seen at Alatri, Segni and at other locations south of the
city: they are called cyclopean, because archaeologists felt
that only the mythical Cyclopes could have moved the
enormous boulders which made up these walls.
Improvements in the tecnique used for cutting stones led to
the construction of walls with stones having the same size
(Isodomum - Vitruvius - De Architectura). In order to
strengthen the wall, blocks were placed alternately with the
longer side (stretchers) or the shorter side (headers) on the
face
of
the
wall
(opus
quadratum).
Romans were so fond of the texture effect of opus quadratum
that they continued to use this technique even after having
developed more effective kinds of masonry. The wall built at
Foro di Augusto with the blocks projecting from the surface
inspired Renaissance
Influence of Roman arches
on Renaissance (left: Palazzo Lancellotti)
and Neoclassic (right: Palazzo Braschi) architecture.
Opus Vittatum
Opus vittatum was a ancient Roman
construction technique, sometimes square
with tuff blocks intersected by one or more
brick-bands at regular or irregular distances,
and Opus caementicium.
This technique was mostly used to erect high
walls, as in the Baths of Caracalla and the
Aurelian Walls in Rome.
Opus vittatum
Oblong (or occasionally square) tufa blocks intersected by one or
more brickbands at (ir-)regular distances
Roman concrete
With the introduction of Roman concrete,
continuous outer walls were often
constructed, with some blocks laid as headers
in order to attach to the inner wall. Tile or
marble can be found cemented to such walls,
but this was less common for those structures
that were particularly load-bearing, such as
arches and pillars used for bridges and
aqueducts.
Opus vittatum mixtum
(wall facing)
Oblong or occasionally
square
tufa
blocks
intersected by one or more
brick bands, at regular or
irregular distances. Square
blocks (re-used reticulate
blocks) appear mainly in
third century masonry.
After that they disappear
as building material. Opus
vittatum mixtum has two
subgroups: A and B. The
distinction is made purely
for chronological reasons.
From the Severan period
throughout late antiquity.
Opus vittatum mixtum A (wall facing)
Alternating oblong tufa courses and brick bands, 1:1. Tufa blocks usually rather well cut.
From the early third century throughout late antiquity. Main appearance in the third and fourth
century.
Opus vittatum mixtum B (wall facing)
Alternating oblong tufa courses and brick bands, in all other combinations than 1:1. Oblong, often rather eggshaped tufa blocks appearing in an irregular number of courses, and alternated at irregular distances with one
or more courses of brick.
Main appearance in later fourth century. Continuing until the Mediaeval period.
Opus vittatum simplex (wall facing)
Oblong tufa blocks without any other interference. Blocks very well cut during the Republic and early
Principate. From the last decades of the Republic mostly found in combination with opus reticulatum. In late
antiquity an increasing tendency to egg-shaped blocks, which appear in the fourth century.
From the Republic until Nero. Re-appears in the third century.
Opus reticulatum mixtum or Opus mixtum (wall
facing)
Masonry of reticulate
(small tufa blocks placed
diagonally) reinforced
and/or intersected by
brick bands (normally five
to six courses). The
reticulate and the bricks
are sometimes
interlocking. The
reticulate fields are rather
large.
Opus (reticulatum) mixtum
Masonry of reticulated material reinforced and/or intersected by
brickbands or interlocked with bricks
Opus Mixtum, Incertum e Testaceum
Amphitheater of Durres
Roman Wall in Ostia: Opus Mixtum of Reticulatum and Testaceum
Opus spicatum (floors)
A floor (or wall) made of quite small, elongated tiles, laid in a
herringbone pattern or in a fishbone pattern.
Opus sectile (floors and walls)
Decoration of walls or floors with marble slabs laid in a regular pattern.
Opus sectile
Decoration patterns and figures at walls (and floors) with precisely cut
pieces of polychrome stone, usually marble
Opus craticium
Term both used for wattlework and walls of half-timer construction,
filled in with stones and/or staw and plastered with mortar
Opus signinum (floors and walls)
Waterproof floor- and wall-revetment consisting of mortar mixed with
terracotta sherds and crushed tiles or bricks.
Opus signinum
Waterproof floor- and wall-revetment of mortar mixed with terracotta sherds and crushed tiles
or bricks
Structure of an arch (Porta Asinaria).
The Romans learned from the Etruscans the use of
arches to make large openings in a wall; the gates of
the Etruscan towns (see for example Arco Etrusco at
Perugia) show the first examples of arch. The laws
of Physics explaining the conditions required for an
arch not to collapse were not fully understood until
the XIXth century; yet the Etruscans, and after them
the Romans, developed empirical methods for
designing arches which still stand more than 2,000
years later.
Etruscan Arch, IIIrd cen AD
Arch included in an "opus quadratum" structure at Arco dei
Pantani
Travertine arches forming
the supporting structure of
Colosseo.
An important aspect the
Romans paid attention to
was the choice of
materials: travertine
proved to resist stress
with limited strain and
was widely employed to
build arches. Roman
architects found also a
way to link the arch to the
wall which was both
effective from a structural
viewpoint and decorative
from an aesthetic one.
Bibliography:
• Jean-Pierre Adam, Anthony Mathews, Roman Building,
1994.
• Lynne C. Lancaster, Concrete Vaulted Construction in
Imperial Rome, Cambridge University Press, 2005.
• Heather N. Lechtman & Linn W. Hobbs, “Roman Concrete
and the Roman Architectural Revolution,” Ceramics and
Civilization Volume 3: High Technology Ceramics: Past,
Present, Future, edited by W.D. Kingery and published by
the American Ceramics Society, 1986.
• W. L. MacDonald, The Architecture of the Roman Empire,
rev. ed. Yale University Press, New Haven, 1982.