1 ARCH 121 – INTRODUCTION TO ARCHITECTURE I WEEK 12

ARCH 121 – INTRODUCTION TO ARCHITECTURE I
WEEK 12:
Structure in Architecture
From: Roth, L., Understanding Architecture: Its Elements, History and Meaning
1. Structure in Architecture
What makes the building stand up is its structure. As we have discussed in the first class,
structure is one of three fundamentals of architecture that Vitruvius listed, next to function
and aesthetics. Up until now, we have discussed the principles and concepts that could be
grouped under the subject of aesthetics. Starting with this class we will talk about the other
fundamentals of architecture, which are structure and function.
We can distinguish between two types of structure:
a. Physical structure: which is the real structure, or the literal bones of the building that
carries the weight of that building, and,
b. Perceptual structure: which is what we see and feel when we look at a structure. For
example, a building could be structurally very solid and its structure could be very
adequate for carrying the load of that building. However, its columns may look so thin
and slender to us that it seems to us very delicate as if to be in danger of a collapse.
Or a column may be much larger than structurally necessary just to give us the feeling
that it is indeed big enough for the job. Such is the case with the thick columns of the
Temple of Poseidon in Italy.
Physical structure: steel frame structure and reinforced concrete frame structure
Physical structure: timber frame structure
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Perceptual structure: Temple of Poseidon at Paestum in Italy (550 BC): The stone columns
larger than structurally necessary, try to convey the impression of strength.
Perceptual structure could also be exemplified by the comparison of two buildings: Lever
House in New York (by Skidmore, Owings and Merrill) and the neighboring New York
Racquet and Tennis Club (by McKim, Mead and White).
We see the contrast in these two buildings between the heaviness of massive masonry wall
that expresses structure and the lightness of the wall of glass that hides the structure. The wall
of New York Racquet and Tennis Club looks stronger than need be and gives us the assurance
of structural excess, whereas the actual physical columns of Lever House are covered by a
suspended skin of green glass and there is no perceptual clue as to what holds the building up.
Perceptual structure: New York Racquet and Tennis Club (by McKim, Mead and White)
shows the heaviness of massive masonry wall (right) and Lever House in New York (by
Skidmore, Owings and Merrill) shows the lightness of the wall of glass that hides the
structure (left).
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We grow up with a good sense of gravity and how it affects objects around us. As babies, we
must figure out how to raise our bodies and move on two legs. So we have a clear concept
that objects not supported will fall straight down. And that is the essence of architectural
structure – making sure that objects (buildings) do not fall to earth, despite the pull of
gravity.
Therefore we develop an early ability about how gravity works on objects. For example when
we see pyramids in Egypt, we sense that they are naturally stable objects, whereas when we
see something like Shapero Hall of Pharmacy (Wayne State University, Detroit), we feel a
sense of instability.
Sense of stability: Pyramids in Egypt
Sense of Instability: Shapero Hall of Pharmacy (Wayne State University, Detroit)
The sense of weight was consciously tried to be expressed by some architects in some
buildings. One example to it is Frank Furness’ Provident Life and Trust Company Building in
Philadelphia (now demolished), which expressed the immense sense of weight.
Sense of weight: Frank Furness’ Provident Life and Trust Company Building
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How forces are handled in buildings also appear in different ways. There could be a careful
balance between the vertical and horizontal structural elements in which neither dominates there is an equilibrium of forces, as in Parthenon, Athens. Or, there could be the dominance of
thin vertical supports and a multiplicity of vertical lines, as in Gothic churches (example:
Beauvais Cathedral, France). In Gothic churches, this verticality conveys the image of
weightlessness, the reach towards God and the visual denial of the actual heavy weight of the
building.
A careful balance between the vertical and horizontal structural elements in which neither
dominates - there is an equilibrium of forces: Parthenon, Athens.
The dominance of thin vertical supports and a multiplicity of vertical lines, as in Gothic
churches: Beauvais Cathedral, France, 42.7 m above the ground.
There are various structural elements and systems (taşıyıcı eleman ve sistemler) that carry the
loads in different ways. As the two most basic systems, we can talk about:
a. The masonry systems in which the walls are carrying the loads, and
b. The frame systems in which the building has a structural system (built out of
reinforced concrete, steel or timber) that carries all the weight.
However, there are also other systems, such as cable structures, shell roofs, pneumatic
structures, space frames etc.
In the following paragraphs we shall talk about the most basic structural elements and systems
in detail:
A. Main structural systems:
a. Masonry (load bearing) systems (yığma taşıyıcı sistem)
b. Frames - Post and Lintel (or the column and beam) systems
B. Structural elements and some other structural systems:
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a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
Post and Lintel (or the column and beam)
Arch
Vault
Dome
Trusses
Space Frames
Geodesic Domes
Shells
Suspension Structures
Membrane (Tent) and Inflated Structures
A. Main structural systems:
A.a. Masonry (load bearing) wall (yığma taşıyıcı duvar):
The most primitive way of carrying the load of the building and the roof is using the walls as
load bearing elements. In this structural system, which is called masonry system, the walls
carry all the weight of the building and the roof.
Basically, masonry is the building of structures from individual units laid in and bound
together by mortar. The common materials of masonry construction are brick, stone, marble,
granite, travertine, limestone, concrete block, glass block, stucco, and tile.
When we want to open door and window openings in load bearing masonry walls, we place a
small beam over the door or window opening (that is made out of wood or metal), which is
called a lintel (lento in Turkish), or an arch that covers the top of the opening.
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Stone masonry and brick masonry buildings
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A.b. Frame Systems
In frame systems, the building has a structural system (built out of reinforced concrete, steel
or timber) that carries all the weight. The basic unit of a frame system is post and lintel
(column and beam). Now before talking about frame systems, we shall talk about post and
lintel in detail:
B.a. Post and Lintel (or the column and beam)
Instead of carrying the load of the building and roof with load bearing walls, we can use posts
(or columns) and lintels (or beams). The column and beam, or post and lintel system is as old
as the history of human construction. Such a system is called a trabeated system (which
comes from the Latin word trabs that means beam).
Two of the most straightforward examples of post and lintel construction is the Stonehenge in
England and the Valley Temple, at the east of the pyramid of Khafre, Giza, Egypt (2570 and
2500 BC). Here square lintels of red granite rest on square posts of same material.
Stonehenge, England
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Valley Temple, at the east of the pyramid of Khafre, Giza, Egypt (2570 and 2500 BC).
Valley Temple, at the east of the pyramid of Khafre, Giza, Egypt (2570 and 2500 BC).
All beams are pulled down by the force of gravity. Since all materials are flexible to some
degree, beams tend to sag of their own weight, and sag even more, when the loads are applied
on it. This means that the upper part of the beam is compressed along the top surface, while
the lower part is stretched and is said to be in tension. In cantilevers the situation is exactly
reversed (extending the beam over the end of the column, results in a cantilever): as the
extended beam sags due to the pull of gravity, the upper part is stretched (put in tension) and
the lower portion is compressed.
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Wood, iron and steel resist tensile stresses well. For this reason, beams of these materials
could span long distances. When the span distance and the load they are carrying are too
much, then the beams crack at the bottom, deform at the top and collapse.
Stone and concrete have less tensile strength then wood, iron and steel, so they cannot span
long distances as wood, iron and steel beams. A wooden beam over a certain span can carry a
load that would crack a stone beam carrying the same load.
The solution that is developed for concrete beams is to place something within the concrete
that will take the tensile forces. This was done by the Romans as well as in modern times, by
placing iron (and now steel) rods in the formwork into which the liquid concrete is then
poured. The result is reinforced concrete. As the dotted lines show in the figure below, the
steel is placed where the tensile forces accumulate: on the bottoms of beams and on the top of
the cantilevers.
The classical column types, or classical orders of Greeks and Romans, work by way of post
and lintel system. As we have talked in the previous classes, the Greeks developed three
column types, which are the Doric, Ionic, and Corinthian. To these the Romans added the
Tuscan, which they made simpler than Doric, and the Composite, which was more ornamental
than the Corinthian.
Each order, or column type, has three basic parts: the base, the shaft and the entablature. The
column rises from the three stepped temple base, which is composed of the one layer of
stylobate (stulos means column and bate means base), and two layers of stereobate.
In all the column types, the basic unit of dimension was the diameter of the column. From the
diameter of column, the dimension of the shaft was derived, as well as the dimensions of the
capital, the pedestal below and the entablature above. The spaces between the columns were
also based on the diameter of the column.
Doric columns (or doric order), the most massive of all the columns, are 6-7 times as tall as
their diameters. Doric entablature is 2 and 1/2 times as tall as the diameter. Generally, the
shaft of the doric order rises directly from the stylobate and has no base. The shaft has 20
flutes. The capital has a necking, an outward swelling echinus and a square abacus slab.
Each order has its distinctive entablature formed of three parts. The Doric order is made up of
(1) the lower architrave, (2) the middle part that is called frieze, which consists of decorated
triglyphs and the metopes between them, and (3) the uppermost cornice.
Ionic columns are more slender than Doric columns. They are 8 and 1/3 times as tall as their
diameters. They rise from a base and have 24 flutes. The capital has curved volutes. The
entablature has again an architrave, a frieze that is generally filled with sculptural reliefs, and
the cornice.
Slightly more slender Corinthian columns are 8 to 10 times as tall as their diameters. They
rise from a base and have 24 flutes. The capital is very tall and has two or three bands of
acanthus leaves decorations. The entablature is similar to Ionic order.
The Romans also used the three Greek orders and added them the Tuscan order (by modifying
the Doric order) and the Composite order (by modifying the Corinthian order). The romans
also introduced a decorative adaptation of columns: merging the column with the wall to
create half columns, which is called the engaged column. They have also created a flat
column like projection on walls, which is called as pilaster.
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Doric order: Parthenon, in Athens, Greece, 432 BC (left), and
Doric order: The Temple of Hephaestus and Athena Ergane. It is the best preserved
ancient Greek temple. Located at the north-west side of the Agora of Athens.
Ionic order: The Temple of Athena Nike in Athens. One of the most famous Ionic
buildings in the world. It is located on the Acropolis, very close to the Parthenon.
Ionic order: The Temple of Athena Nike in Athens. One of the most famous Ionic
buildings in the world. It is located on the Acropolis, very close to the Parthenon.
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Corinthian order: The Temple of Olympian Zeus in Athens
Corinthian order: The Temple of the Sybil in Rome is a good example of the
Corinthian order: The Romans used the Corinthian order much more than did the Greeks.
Corinthian order: Maison Carrée, Nîmes, southern France (Roman building)
Tuscan order: John Wood the Younger’s Hot Bath (1776-1778)
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Tuscan order: Bernini’s St Peter’s Basilica (left)
Composite order: Baths of Diocletian, Rome
Engaged Column
Engaged Column
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Pilaster
A.b. Frames
As we had seen, the most basic unit of a frame system is the post and lintel. If posts and
lintels are extended in three dimensions (continued in x and y axes), the result is a frame
(cerceve). Frame systems could be built out of stone ( The Valley Temple in Egypt above),
reinforced concrete, steel or timber.
Reinforced concrete frame
Reinforced concrete frame
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Reinforced concrete frame: Rue Franklin Apartment- First reinforced concrete apartment by
Auguste Perret in France
Reinforced concrete frame: Le Corbusier’s Domino House drawing
Reinforced concrete frame: Le Corbusier’s Villa Savoye
Steel frame
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Steel frame
Steel frame: Mies van der Rohe’s Seagram building, New York
Timber frame
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Timber balloon frame
Timber frame: Safranbolu houses
B. Structural elements and some other structural systems:
a. Post and Lintel (or the column and beam) (We had already discussed this)
b. The Arch
Arch is another method of spanning an opening. Like a lintel, the arch (kemer) can be made of
stone but it has two great advantages: (1) the masonry arch is made up of many smaller parts,
which are the wedge shaped voussoirs, so the necessity of finding a large stone lintel is
eliminated, and (2) the arch can span much greater distances than a lintel, because of its
geometry. The gravitational forces are transferred from the voussoirs to wall below. The
uppermost voussoir is called the keystone.
The arch is made by placing the voussoirs above a wooden framework, when all the voussoirs
(both on left and right) are placed, the keystone is put in place and that instance the arch
becomes self-supportive. Then the wooden framework can be removed. The base of the arch
tends to spread outwards if it is not supported by wall or other supportive elements, such as
other arches. There are several arch types.
Arches and vaults (information below) were first used systematically by the Ancient Romans.
Romans were the first to apply the technique to a wide range of structures.
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If several arches are placed end to end, the resulting form is called an arcade. Arcade is a
strong structure because every arch supports each other and prevents each other to spread
outwards. When this is done the arches can be placed on piers or individual columns, since
the lateral forces that make the bases of the arches spread out are cancelled. The lateral forces
are eliminated at the ends of the arcade by building thicker piers at the end or placing the
structure in a canyon. The Romans used arcades very much (especially in building aqueducts).
One example is Pont du Gard, in Nimes, France, a combination of bridge and aqueducts. The
arches in this structure span 19.5 m and the total length of the bridge is 274.3 m.
Triumphal Arch in Tyre, Lebanon (left), and Arc de Triomphe in Paris, France
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Arcade
Pont du Gard, in Nimes, France
Pont du Gard, in Nimes, France
c. Vault
If the arch is extended in one direction, the result is a vault (tonoz). If a semicircular arch is
extended the result is a tunnel or barrel vault (besik tonoz).
Solid barrel vaults produce dark interiors. To overcome this, the Romans developed the groin
vault (capraz tonoz) by adding two barrel vaults to the main vault at right angles, so that they
are intersected.
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But groin vault also had a distadvantage that it worked well only over square plans. To
overcome this, in 1100 in England, the architects have developed the ribbed vault, which
consisted free standing diagonal arches (the ribs) that were placed at the intersection of
separate vaults. They were increasing the strength of the intersection and for this reason the
architects were able to cross rectangular plans with ease.
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Ribbed vault
Barrel vault: Basilica of Saint-Sernin, Toulouse, France
The painted barrel vault at the Abbey Church of Saint-Savin-sur-Gartempe
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A reconstruction of the interior of the Baslica of Maxentius, Rome is a demonstration how
Romans could cover vast public spaces with concrete vaults
A reconstruction of the interior of the Baslica of Maxentius, Rome is a demonstration how
Romans could cover vast public spaces with concrete vaults
Groin vault: Palladio's Palazzo della Ragione, Vicenza (left) and Abbaye Saint-Philibert,
Tournus
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The aisle of the Abbey Church at Mozac has a groin vault supported on transverse arches
(left); Groin vault of the nave, 12th century. Gourdon Church, Burgundy, France.
The ribbed vaults at the Saint-Etienne, Caen (left) and the aisles at Peterborough Cathedral
with quadripartite ribbed vaults.
Rib vault: Cathedral of Reims, France (left), and Notre dame de Amiens in France (right)
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d. Dome
If an arch is rotated in three dimensions, we get a dome. The dome too was much used by the
Romans.
The largest and most impressive dome created in Roman times was the Pantheon in Rome
(AD 120-27). Originally it was a pagan temple (before Christianity). The clear span under the
dome of Pantheon is 43.4 m. The dome is made up of concrete and its thickness is 1.2 m at the
top. The thickness of the dome is increased at its base for preventing the spreading outwards
and it is 6.4 m thick. On top of the dome there is a big opening, called the eye (or the oculus),
which is 9.1 m in diameter. The wall under the wall (drum wall) is also 6.4 m thick and
supports the 5000 tons of weight of the dome. The wall is hollowed by niches that are 4.3 m’s
deep.
The weight of the concrete in Pantheon was varied by the Roman architects by means of the
materials used to make up the concrete. As we had seen before, the concrete in our time is a
soft material when it is first prepared, which is a mixture of water, broken rocks and sand
(aggregate) and cement. It is placed into a formwork until it is dry. In the concrete of the
Pantheon, the rock aggregate was varied from the heaviest at the base of the dome to the
lightest at the top.
Pantheon in Rome (AD 120-27)
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Floor plan and Cross-section of the Pantheon in Rome showing how a 43.3 m-diameter sphere
fits under its dome.
The interior of the Pantheon in the 18th century, painted by Giovanni Paolo Panini
Pantheon in Rome (AD 120-27)
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Of course there is a difference between the Roman concrete and the concrete we use today.
The Romans used pozzuolana instead of cement, which is a volcanic ash that underwent a
chemical reaction and turned into an artificial stone when mixed with water. Therefore the
Roman concrete was made up of water, broken rocks and sand (aggregate) and pozzuolana.
The concrete we used today was developed in 1824 in England by Joseph Aspdin and consists
of water, sand (aggregate) and cement. When it was first made, the dried out concrete
resembled the natural limestone of Portland, England and the inventor Aspdin called the
cement he developed as Portland cement. Cement is still called with this name today.
As it has been mentioned before, concrete is very strong for compression (pressure) but very
week for tension (pulling out). For this reason, both the Romans and us in our time, add
tensile membranes into concrete when it is soft. Romans added iron bars and we add iron or
steel bars within the formworks of concrete since mid-19th century. The steel or iron bars are
placed where the tensile forces are much greater (at the top of the cantilever and at the bottom
of the beams).
The domes naturally require circular plans underneath them. Any building with a circular
ground plan, which is covered by a dome, is called a rotunda. The Pantheon is a famous
rotunda. But circular plans are generally disadvantageous for adding adjacent spaces next to
the domed space. For this reason in 4th century AD, the Byzantine architects have developed a
way of placing a dome over a square plan. They have achieved this by using curved triangle
shaped elements which are called as pendentives (singular: pendentive. Turkish: pandantif).
(The four curved segments that make the transition from the square plan below to the circular
plan above are the pendentives.) By this way they were able to put a circular dome over a
cubical space. An excellent example to the use of pendentives is Hagia Sophia Church (Aya
Sofya) in Istanbul, designed by Isidoros of Miletos and Anthemios of Tralles. The space
enclosed in Hagia Sophia is huge: it is 32.6 meters across, but with the extended domes it
reaches to 76.2 m’s. the base of the dome is 40.2 m’s high from the ground.
The weight of the dome spreaded the dome outwards when it was first constructed (and after
the earthquakes) and it was collapsed two times. It was built again and this time to prevent
spreading, very big buttresses (destek payandalari in Turkish) have been built against the
pendentives.
If there is a square plan and it is connected to an octagonal or spherical base of the dome, the
dome is connected to the square plan by squinches. A squinch (tromp in Turkish) is a
construction filling in the upper angles of a square room so as to form a base to receive an
octagonal or spherical dome.
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Pendentives: Hagia Sophia (Church of Divine Wisdom) in Istanbul (532-537 AD)
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Pendentives: Hagia Sophia (Church of Divine Wisdom) in Istanbul (532-537 AD) designed
by Isidoros of Miletos and Anthemios of Tralles.
Squinches
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Squinches supporting a dome in Odzun Basilica, Armenia, early 8th century (left)
e. Trusses
The Romans also used another structural element, which is the truss. The traditional truss was
made up of timbers arranged in triangular shapes or cells. The triangle, by way of its
geometry, cannot be changed in shape without distorting or bending one of its sides. Because
of this the trusses, which are formed by triangles, are very strong and durable against loads.
One good example of a wooden truss in medieval times is the roof of Westminster Hall,
London, built in 1394-99, which spans 20.7 m’s. It has the hammer-beam type of truss. Today
trusses are generally made by using steel.
Westminster Hall, London, built in 1394-99, which spans 20.7 m’s
Westminster Hall, London, built in 1394-99, which spans 20.7 m’s
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There are different types of trusses, developed in different times (in 19th century, they were
often named by the name of the engineer who developed them):
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Wooden truss and steel truss
When built up of steel members, truss can span huge distances and cover big areas. One of the
first examples to such a use of steel truss is Gallery des Machines, which was built for the
international exhibition held in Paris in 1889. It spanned a 114.9 m’s of distance.
Steel truss: Gallery des Machines, which was built for the international exhibition held
in Paris in 1889
Steel truss: Gallery des Machines, which was built for the international exhibition held
in Paris in 1889
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Butterfly truss in Saynatsalo Town Hall by Alvar Aalto
Trusses are also used extensively in bridges
A three dimensionally trussed structure is called a pylon
The HSBC Main Building, Hong Kong has an externally visible truss structure (architect:
Norman Foster) (left); The Hong Kong Bank of China Tower has an externally visible truss
structure. (right)
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f. Space Frames
If truss is extended in three dimensions, we attain a new structure called the space frame. It is
being used since 1945 to span very big distances. It can also cantilever big distances. One
early example to it is McCormick Place, Chicago, by C. F. Murphy and Associates in 1968.
Space frame
Space frame: McCormick Place on the Lake, Chicago, C. F. Murphy and Associates, 1968
(spans 45.7 m’s)
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Space frame: McCormick Place on the Lake, Chicago, C. F. Murphy and Associates, 1968
(spans 45.7 m’s)
The use of three dimensional trusses that carry the roof: R. Kemper Memorial Arena by
Murphy and Associates, Kansas City, Missouri, 1975. Designed by Helmut Jahn (spans 104.2
m’s)
The use of three dimensional trusses that carry the roof: R. Kemper Memorial Arena by
Murphy and Associates, Kansas City, Missouri, 1975. Designed by Helmut Jahn (spans 104.2
m’s)
g. Geodesic Domes
A truss can be curved in three dimensions to form a geodesic dome. It was invented by the
architect Buckminster Fuller in 1945. Like the steel truss it is formed by triangular steel
elements. One of the first geodesic domes of Fuller is in United States Pavilion for the
international exhibition in Montreal, Canada, built in 1967.
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Geodesic dome
Geodesic dome: Montreal Biosphere or United States Pavilion for the international exhibition
in Montreal, Canada, built in 1967 by Buckminster Fuller.
Geodesic dome: Montreal Biosphere or United States Pavilion for the international exhibition
in Montreal, Canada, built in 1967 by Buckminster Fuller.
Geodesic dome: The Climatron greenhouse at Missouri Botanical Gardens, built in 1960 and
designed by Thomas C. Howard
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h. Shells
Another structural type is the shell. Generally constructed of concrete, shells are durable and
strong because of their curved geometry. With their curved shapes, shells are naturally strong
structures, allowing wide areas to be spanned without the use of internal supports, giving an
open, unobstructed interior. They can be very strong and safe. And they can be very thick and
heavy or extremely thin and light. Shells can be curved or folded in one direction (folded
plate).
Shell structure: Oceanografic Valencia (left) and Heinz Isler Concrete Shell
Shell structure: Chapel Lomas de Cuernavaca. Designer: Felix Candela
Shell structure: Kresge Auditorium, Massachusetts Institute of Technology, by architect Eero
Saarinen, in 1953.
Shell structure: Kresge Auditorium, Massachusetts Institute of Technology, by architect Eero
Saarinen, in 1953.
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Shell structure: TWA Flight Center Building by Eero Saarinen, John F. Kennedy International
Airport, New York (spans 64.6*88.7 m’s). The cantilevers are very big: 24.9 m’s.
Shell structure: TWA Flight Center Building by Eero Saarinen, John F. Kennedy International
Airport, New York
Shell structure: : Oceanografic Valencia (left); Los Manantiales Restaurant at Xochimilco by
architect-engineer Félix Candela, 1958 (the concrete applied by hand over steel wire mesh.
The concrete thickness is only 10 cm.)
Shell structure: Los Manantiales Restaurant at Xochimilco by architect-engineer Félix
Candela
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Shell structure curved in one direction (folded plate): Minneapolis International Airport, 1962
Shell Structure: Assembly Hall, University of Illinoi, Urbana, 1961. The dome consists of a
folded plate that spans 120 m’s. The lateral forces at the end of the shell are taken by a huge
steel belt at its end.
i. Suspension Structures
Beginning from 19th century the suspension bridges are began to be built of iron chains or
steel cables. The classic example of a modern suspension bridge is the Brooklyn Bridge, built
in 1867-83, by John Augustus Roebling, in New York. In this bridge steel wire was used in
the cables.
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Suspension bridge: Brooklyn Bridge, built in 1867-83, by John Augustus Roebling, in New
York. In this bridge steel wire was used in the cables.
Suspension bridge: Bogazici Bridge (1970-73) spans 1.560 m.
Suspension bridge: Bogazici Bridge (1970-73) spans 1.560 m.
Suspension bridges could also be cable-stayed:
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The Millau Viaduct , France
Firth of Forth Bridge in Scotland (left), Campo Volantín footbridge, Bilbao, Spain, Santiago
Calatrava (right)
El Alamillo Bridge, Spain, by Santiago Calatrava
Since 1955, the principles of cables in tension have started to be used in buildings too. A
suspended cable is in the form of a curve, just like a parabola, and it is an ideal structural
form, because it is entirely in tension. Its geometrical reverse, which is a parabolic arch is in
full compression, and it is also an ideal structural form. The architect has attained the shape of
his vaults in La Sagrada Familia Church in Spain, by holding the cables downwards.
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Look at this experiment with strings upside down and you will see La Sagrada Familia
Church in Spain by Gaudi
Look at this experiment with strings upside down and you will see La Sagrada Familia
Church in Spain by Gaudi
La Sagrada Familia Church in Spain by Gaudi
Tension is used by way of using cables in buildings that carry the roof. The cables are
supported by way of beams or columns at the ends. One such example is Eero Saarinen’s
Washington Dulles Airport Building, 1958. He created two rows of outward leaning
coulumns that carry two parallel beams on the two long sides of the building. Between these
parallel beams, the cables are suspended. Concrete slabs were placed on these suspended
cables to form the roof.
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Eero Saarinen’s Washington Dulles Airport Building, 1958
Eero Saarinen’s Washington Dulles Airport Building, 1958
Another example is Federal Reserve Bank in Minneapolis by Gunnar Birkerts, in 1971. This
building was required to have an uninterrupted space in the ground floor, therefore architect
was not allowed to put any columns in the area below. For this reason he has developed the
idea to carry the entire building on cables suspended form the tops of two towers at the ends,
just like a suspension bridge. At the roof, a huge truss is used to keep the towers apart.
Federal Reserve Bank in Minneapolis by Gunnar Birkerts, in 1971
Buildings could also be suspended by cables from a single column support. An example is
Westcoast Transmission Building, Vancouver, Canada, 1968-69.
Westcoast Transmission Building, Vancouver, Canada, 1968-69.
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Cable tensile structure: Renault Distribution Centre, Wilshire, UK (Norman Foster and
Partners)
j. Membrane (Tent) and Inflated Structures
Since early 1960’s, tent membrane structures and inflated (pneumonic) structures have started
to be built. The German architect Frei Otto created membrane structures in which the tent is
supported by masts carrying a net of interwoven cables stretched and anchored in the earth.
To this net, the membrane was attached. Good examples to this are Otto’s German Pavilion
for the international exhibition in Montreal Canada, 1967; and 1972 Munich Olympic
Stadium.
Tent-membrane structures
Otto’s German Pavilion for the international exhibition in Montreal Canada, 1967
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Otto’s German Pavilion for the international exhibition in Montreal Canada, 1967
1972 Munich Olympic Stadium
Millenium Dome, 2000, London
Another new building type is inflated (pneumatic) structures. They are generally made for
covering the spaces (like swimming pools or fair spaces) temporarily. There are two types of
inflated (pneumonic) structures according to their method of working: (1) the structures which
are kept inflated by keeping the air pressure within the structure high by pressurized fans, and
(2) the structures that have a double wall inflated tubes, which do not require constant
pressure arrangement.
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Inflated (pneumatic) structures – type 1: the structure is kept inflated by keeping the air
pressure within it high by pressurized fans
Inflated (pneumatic) structures – type 1: the structure is kept inflated by keeping the air
pressure within it high by pressurized fans
Inflated (pneumatic) structures – type 2: the structure has a double wall with inflated tubes,
which does not require constant pressure arrangement (Yukata Murata’s Fuji Pavillion, 1970,
World’s Fair, Japan)
Therefore designing is also the selection of the structural system. The selection of
structure defines your architectural design. It defines your spaces and sugggests either
massiveness or lightness.
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