Each building is drawn for one idea it added to how we build: a new way to span a room, carry a load, let in light or lay out a plan. Scroll down through 11,500 years, from carved pillars in Anatolia to the frame that freed the modern wall.
30 buildings, each with its sources listed beside it.
01Neolithic, 9,500 BCE to 3,000 BCEc. 9500 BCEŞanlıurfa, Turkey
Göbekli Tepe
Monuments came before farming.
Fig. 1a Section across Enclosure D, looking past the two central pillars to the far wall. The pillars stand on low pedestals carved from the bedrock. Simplified from published plans; the head and shaft widths are estimates.
Central pillar
Carved arms and hands
Stone wall
Pedestal of bedrock
Bedrock
Earth fill
Rings of carved limestone pillars, the tallest 5.5 metres and eight to ten tonnes, stand on low pedestals carved from the bedrock. They were raised by people who still lived by hunting and gathering, in the centuries when farming was only beginning in the region. Later digs found houses and water cisterns, so it was never the lonely temple first described. It is still among the oldest monumental buildings known.
Fig. 1b Pillar 18 drawn larger. The T is a figure: the crossbar is the head, and arms, hands, a belt and a fox pelt are carved into the shaft.
Head
Arms
Hands meet
Belt
Fox pelt
Pedestal
02Neolithic, 9,500 BCE to 3,000 BCEc. 7100 BCEKonya, Turkey
Çatalhöyük
A town with no streets, entered through the roof.
Fig. 2a Section through six houses built wall against wall. There are no streets or doors at ground level: people walked across the roofs and climbed down ladders. The red line follows the way in.
Roofs were the streets
Hatch and ladder
Each house has its own walls
Platform
Oven below the hatch
Older houses buried below
In a typical year perhaps 600 to 800 people lived here, in mudbrick houses packed so tightly that there were no streets. You crossed the town on its roofs and climbed down a ladder through a hatch, which also let out the smoke from the oven below. When a house wore out it was filled in and a new one built on top, so over more than a thousand years the town rose into a mound 21 metres high. The dead were buried under the floors.
Fig. 2b The roof hatch was both door and chimney. Smoke from the oven rose out past the ladder people climbed in by. The dead were buried under the platforms.
Fig. 3a Section looking west. Almost all of it is solid stone; the passages and chambers are drawn slightly wider than true so they read at this scale. The top 8 metres, above the dashed line, are now missing.
Apex, now missing
Relieving chambers
King's Chamber
Grand Gallery
Queen's Chamber
Entrance
Descending passage
Rock-cut chamber
Built for the pharaoh Khufu from about 2.3 million blocks, it rose 146.6 metres and stayed the tallest structure on Earth for almost 3,900 years. It is nearly solid: the structure is simply its own weight, stacked at a slope of about 52 degrees. The hard part was the few rooms inside. Over the King's Chamber, five low compartments and a roof of leaning blocks steer the weight of the stone above around the room and into its walls.
Fig. 3b Five low compartments and a gabled roof sit over the King's Chamber. The leaning blocks of the gable push the weight above out to the walls, so it goes round the room rather than onto its granite ceiling.
Weight from above
Gabled roof
Relief chambers
Granite beams
Cracked beam
King's Chamber
Load goes round the room
04Indus Valley, 2,600 BCE to 1,900 BCEc. 2500 BCESindh, Pakistan
Mohenjo-daro
The planned grid and the covered drain.
Fig. 4a A representative plan, not a survey. The street widths, lanes and house sizes follow the lower town, but the houses are schematic. Covered drains, in red, run along the streets, with inspection holes and short drains coming in from the houses.
N
Main street
Covered drain
House drain
Inspection hole
Well
Narrow lane
Courtyard house
One of the largest cities of the Indus civilisation, laid out with main streets running north to south and east to west, and narrow lanes between blocks of houses. It was built of fired bricks made to the same proportions. Almost every house had a bathing floor, and many had their own well. Waste water ran down chutes into covered brick drains along the streets, with holes where they could be cleared. Few cities had anything like it for thousands of years.
Fig. 4b Water from an upstairs bathing floor runs down a chute in the wall into a brick sump at the street edge. Silt settles there; the water flows on into the covered drain under the street.
Bathing floor
Chute in wall
Covered street drain
Sump catches silt
Lift bricks to clean it
05Greek, 800 BCE to 146 BCE447–432 BCEAthens, Greece
Parthenon
Post and lintel, bent so it looks straight.
Fig. 5a West front restored to its finished state, without the pediment sculpture. Eight Doric columns; the corner gaps are narrower so the triglyphs can meet at the corners.
Pediment
Frieze
Architrave
Capital
Column
Three steps
Columns carry stone beams, and the beams carry a roof. The system is ancient; the Parthenon perfects it. The floor rises about 11 centimetres towards the middle of each long side, the columns lean slightly inward and swell as they rise, and the corner columns are thicker. A building made only of straight lines can look like it sags. This one was bent on purpose so that it reads as straight.
Fig. 5b Dashed lines are truly level and plumb; the red lines are what was built. The real floor curve is about 11 cm over 70 m, far too small to see as a curve.
Floor rises towards the middle
Columns lean in
Shafts swell slightly
Corner columns thicker
06Mauryan, 322 BCE to 185 BCE3rd century BCESanchi, India
Great Stupa
A building you walk around, not into.
Fig. 6a Elevation from the south, through the south gateway, with the double stair rising behind it. The dome is solid. The red line is the upper path on the drum, walked clockwise like the ground path inside the railing.
Solid dome
Harmika and umbrellas
Gateway (torana)
Upper path
Stone railing
The emperor Ashoka built the first stupa here in the 3rd century BCE over relics of the Buddha. About a century later it was cased in stone and roughly doubled in size, and four carved gateways followed. The dome is solid, with no room inside. The building is the route around it: pilgrims walk clockwise on a paved path inside the railing, then climb to a second path on the drum. The stone gateways copy timber joints, a trace of the wooden railings that came first.
Fig. 6b Plan of the stupa. Pilgrims enter through a gateway, walk clockwise on the ground path inside the railing, then climb the south stair and circle again on the drum. There is no way in.
Walk clockwise
Solid dome
Ground path
Upper path
Gateway
Stair
07Roman, 146 BCE to 476 CEc. 114–126 CERome, Italy
Pantheon
A concrete dome that gets lighter as it rises.
Fig. 7a Cross-section through the rotunda, with the portico left off. The dashed red circle is the sphere the room is built around: 43.3 m wide and 43.3 m from floor to oculus.
Oculus, open to the sky
Shell thins to 1.2 m
Step rings
Wall 6.4 m thick
A sphere fits inside
Niche
The dome is 43.3 metres across, and the floor to the top of the dome is the same, so a perfect sphere would fit inside. Roman builders made it from unreinforced concrete, laid in horizontal layers. The mix changes with height: heavy travertine in the walls, tufa and brick in the lower dome, light volcanic pumice near the top. The shell thins from over 6 metres to 1.2 metres around the open oculus. Nineteen centuries later it is still the largest unreinforced concrete dome in the world.
Fig. 7b Half the wall and dome, drawn larger. The stone mixed into the concrete gets lighter with height. The heights where one mix gives way to the next are estimates.
Travertine and tufa
Tufa and brick
Pumice and tufa
1.2 m at the top
Wall 6.4 m
08Early medieval, 476 CE to 1000532–537Istanbul, Turkey
Hagia Sophia
Pendentives put a round dome on a square.
Fig. 8a Section along the church, looking north, with the dome as rebuilt after it fell in 558. Cut parts are hatched. The red curved triangles are the pendentives that carry the round dome on four arches.
Dome, rebuilt in 562
Ring of 40 windows
Pendentive
Half-dome
Gallery
Narthex
Apse
Justinian's church went up in under six years, designed by Anthemius of Tralles and Isidore of Miletus, both mathematicians. A round dome needs a round base, but four piers make a square. The answer was the pendentive: curved triangles of masonry that turn the square into a circle. Pendentives had been used before, never at this size. A ring of 40 windows at the base makes the dome seem to float. The first dome fell in 558 and was rebuilt steeper; it has stood since.
Sources: Wikipedia, Hagia Sophia. Estimated from drawings and photographs: dome base height, main arch springing.
Fig. 8b Four arches stand on a square. The pendentives, shaded, are curved triangles cut from one sphere; they fill the corners between the arches and finish in a circle. The dome sits on that circle, in red.
Dome
Ring
Arch
Pendentive
Pier
09Asuka, 538 CE to 710 CElate 7th centuryNara, Japan
Hōryū-ji
A timber pagoda that sways and does not fall.
Fig. 9a Elevation of the pagoda. Each storey is smaller than the one below; the top is about half the width of the first. The red dashed line is the central pillar, hidden inside, running from a stone below ground up into the spire.
Tip of the spire
Spire with nine rings
Top storey half as wide
Central pillar, hidden
Deep eaves
Brackets
The temple was founded by Prince Shōtoku in the early 7th century and rebuilt after a fire in 670; its pagoda and main hall are among the oldest timber buildings in the world. The five storeys are stacked rather than fixed together, each smaller than the one below. A tall central pillar runs up the middle without carrying any floor. In an earthquake the storeys sway in turn and the pillar calms them, and Japanese pagodas have very rarely fallen.
Fig. 9b Diagram, movement exaggerated. The storeys rest on each other without rigid joints. In an earthquake they swing in alternate directions, and the free central pillar knocks against them and calms the swing. This is the usual explanation; engineers still argue over how much each part does.
Free pillar
Rest position
Storeys sway
Loose joints
Stone base
10Umayyad, 756 CE to 1031785 onwardsCórdoba, Spain
Great Mosque
Arches stacked on arches to lift a low hall.
Fig. 10a A row of the prayer hall's arcades, from the first building phase. The reused columns were too short for a tall hall, so a pier stands on each one and carries a second tier of arches. The overall height is an estimate.
Upper arch
Brick and stone
Horseshoe brace
Pier on column
Reused Roman column
Abd al-Rahman I began the prayer hall in 785, reusing columns from Roman and Visigothic buildings. They were too short for a tall hall, so the builders stood a pier on each column and set two tiers of arches: horseshoe arches below to brace the supports, round arches above to carry the roof. The arches alternate red brick and white stone. Three later extensions turned the hall into a forest of more than 850 columns.
Fig. 10b The roof's weight comes down the pier and onto the column. The horseshoe arches below tie each pier to the next, so the tall, thin supports cannot buckle sideways.
Weight down
Pier
Braces
Impost block
Column
11Shailendra, 750 CE to 850 CEc. 800Java, Indonesia
Borobudur
A mountain built as a path.
Fig. 11a Elevation of one side. The red dashed lines are the gallery paths behind each balustrade, walked clockwise past the carved reliefs before the stair takes you up a level. The base was later wrapped in a broad foot that hides its first row of reliefs.
Central stupa
72 latticed stupas
Three round terraces
Four galleries of reliefs
Hidden foot
Stair on each side
Built in central Java around 800, Borobudur has no interior. It is a stepped mountain of stone wrapped around a hill, made to be climbed. Pilgrims walk clockwise round four galleries carved with relief panels, rising level by level, until the walls fall away on three open round terraces. There, 72 latticed stupas each hold a seated Buddha around a great central stupa.
Fig. 11b Plan, with the route in red. Pilgrims enter from the east, circle each square gallery clockwise, climb, and circle again, about 5 km in all, before the round terraces lead to the central stupa.
Start at the east stair
Square galleries
Walk clockwise
Round terraces
12Romanesque, 1000 to 11501093–1133Durham, England
Durham Cathedral
The rib vault: a frame of arches under a thin shell.
Fig. 12a Cross-section through a nave bay, looking east. Cut parts are hatched; the round piers, ribs and arches are seen beyond. The ribs of the high vault are in red. Under the gallery roofs, quarter arches brace the nave wall: flying buttresses before they learned to fly. They were enlarged in the 19th century.
Rib vault
Pointed transverse arch
Diagonal rib
Hidden quarter arch
Thick wall
Carved round pier
Gallery
Aisle
Begun in 1093, Durham was planned from the start to be vaulted in stone, and its vaults are among the earliest rib vaults in Europe. Arched ribs went up first across each bay, and thin panels of stone were filled in between. The nave's transverse arches, finished by about 1133, are pointed, decades before Gothic made that normal. Under the gallery roofs, hidden quarter arches brace the walls: an early form of the flying buttress.
Fig. 12b One bay of the vault. The diagonal ribs, in red, are semicircles over the long diagonals, so they rise higher than a round arch over the shorter sides could. Pointing the side arches lets them reach the same height. The ribs went up first; the thin web was filled in between them.
Diagonal ribs
Pointed arch
Thin web
Pier
13Khmer, 802 CE to 1431c. 1113–1150Siem Reap, Cambodia
Angkor Wat
Corbelled galleries around a model of the cosmos.
Fig. 13a Elevation from the west, across the moat causeway. Three rings of galleries step up to the central terrace and its five towers. The plan sizes are surveyed; the heights of the terraces and corner towers are estimates.
Central tower
Corner towers
Upper terrace
Steep stairs
Second gallery
Outer gallery of reliefs
Built for Suryavarman II in the first half of the 12th century, Angkor Wat is a model of the Hindu cosmos in stone. Five towers stand for the peaks of Mount Meru, three rings of galleries for the mountain ranges around it, and the moat for the ocean. Khmer builders never used the true arch. Every gallery is roofed by corbelling, stones stepped in course by course until they meet, which keeps the galleries narrow: the outer one is under 2.5 metres wide inside.
Fig. 13b Section through the outer gallery. There is no true arch and no keystone: each course of stone steps in a little past the one below, held in place by the weight on its tail, until the two sides meet. Corbelling only spans a few metres, so the galleries are long and narrow.
No keystone
Courses step in
Half-vault
Square pillar
Relief wall
14Gothic, 1150 to 14001194–1220Chartres, France
Chartres Cathedral
The flying buttress replaces the wall.
Fig. 14a Cross-section through the middle of a nave bay, looking east. Cut parts are hatched; the piers, ribs and flying buttresses are seen beyond. The red line follows the push of the vault down to the ground.
Stone vault
Flying buttress
Buttress pier
Clerestory window
Thrust reaches the ground
Timber roof
Aisle
A stone vault pushes outward as well as down. Romanesque churches resisted the push with thick walls and small windows. At Chartres, rebuilt after a fire in 1194, the push is caught by arches that fly over the aisle roofs to heavy piers outside. With the walls no longer holding anything up, they could become glass. The vault is 37 metres up, and the church still has most of its 13th-century windows.
Fig. 14b The push of the vault, traced in red. The flyer carries it over the aisle, the weight of the pinnacle bends it downward, and it reaches the ground inside the pier.
Vault pushes out
Flyer carries it across
Pinnacle adds weight
Push turns down
Lands inside the base
15Great Zimbabwe, 1100 to 1450c. 1300Masvingo, Zimbabwe
Great Zimbabwe
Granite walls laid without mortar.
Fig. 15a Section through the outer wall where it runs beside the conical tower. Both faces lean inward, more steeply above about 4 m, which narrows the wall from 5 m at the base to under 2 m at the top; the red dashed lines are plumb. The inner wall and passage are estimates.
Granite blocks, no mortar
Narrow passage
Solid conical tower
The capital of a trading state on the Zimbabwe plateau, built between the 13th and 15th centuries by ancestors of the Shona. The outer wall of the Great Enclosure runs about 250 metres round and rises to about 11 metres, made of dressed granite blocks with no mortar at all. Both faces lean inward, so the wall narrows as it rises and its weight holds it together. Inside stands a solid conical tower, and a band of chevrons runs along the top of the wall.
Fig. 15b The outer face near the top, with its band of chevrons. Every block rests across a joint in the course below, and the wall stands by weight and fit alone.
Double chevron band
Block bridges a joint
Dry courses
16Ming, 1368 to 16441406–1420Beijing, China
Forbidden City
Dougong brackets let a heavy roof flex.
Fig. 16a The hall as rebuilt in 1695, on its three-tier marble terrace. Bracket sets, in red, sit between the columns and both tiers of eaves. The roof and bracket profiles are drawn from photographs and are approximate.
Ridge ornament
Double hipped roof
Dougong brackets
Timber column
Three-tier marble terrace
The palace was built for the Yongle Emperor between 1406 and 1420; the Hall of Supreme Harmony standing today is a rebuilding of 1695. It is a timber frame of 72 columns on a three-tier marble terrace, under a double hipped roof. Between columns and roof sit dougong: interlocking brackets of small blocks and arms, fitted without nails, that gather the weight of the deep eaves onto the columns and let the joints give a little in an earthquake.
Fig. 16b A bracket set drawn larger. Wooden arms and small blocks stack in tiers, each wider than the one below, so the weight of the eaves gathers onto the column. The joints are fitted, not nailed, and can rock a little without coming apart.
Eave purlin
Arms widen
Small blocks
Cap block
Column
17Renaissance, 1400 to 16001420–1436Florence, Italy
Florence Cathedral dome
A dome built without scaffolding from the ground.
Fig. 17a Section across the corners of the octagon. Two shells of brick rise from the drum on the pointed-fifth curve, the thick inner one carrying the thin outer one, with a gap between them for stairs. The red marks are the stone and timber chains that hoop the dome. The drum, piers and lantern are simplified.
Lantern
Thin outer shell
Thick inner shell
Stone and timber chains
Drum
For decades the cathedral had a hole in it: an octagon 45 metres across and 55 metres up, too wide to bridge with wooden centring. Filippo Brunelleschi built the dome from 1420 to 1436 as two shells of brick, a thick inner one carrying a thin outer one, tied by ribs and by chains of stone and timber. The bricks were laid in a herringbone pattern, so each course was locked in place as it went up and the dome held itself while it rose.
Fig. 17b A patch of the inner shell. Upright bricks, in red, are set into the flat courses at intervals and shift along a little in each course, so they climb the dome in spirals. Each upright held the next course in place while its mortar set, which is how the dome rose without wooden centring.
Flat courses
Upright bricks lock it
Spirals up the dome
18Inca, 1438 to 1533c. 1450Cusco, Peru
Machu Picchu
Fitted stone that shakes loose and settles back.
Fig. 18a Elevation of a fine stone wall with three trapezoidal windows, standing on a terrace of rougher stone; on the right, a section through the wall. The wall leans inward by about 4 degrees; the red dashed line is plumb. Wall, window and block sizes are estimates drawn from photographs.
Dry-laid stone
Trapezoidal windows
Single lintel
Leans in
Terrace wall
Built for the Inca ruler Pachacuti around 1450 on a ridge high in the Andes, in a region of frequent earthquakes. Its finest walls are dry-laid: every stone shaped to fit its neighbours so closely that no mortar was needed. Walls lean inward by a few degrees, and doors, windows and niches narrow towards the top. When the ground shakes, the stones can move against each other and settle back into place.
Fig. 18b Close-fitted masonry. Each stone is cut to the shape of its neighbours, with joints too tight for mortar. In an earthquake the stones can shift against each other and settle back into place.
Cut to fit its neighbours
No mortar in the joints
19Ottoman, 1453 to 17001550–1557Istanbul, Turkey
Süleymaniye Mosque
A dome held up by a cascade of half-domes.
Fig. 19a Section along the main axis, with the half-domes in red and one of the tall minarets beyond. The dome rises to twice its width. The pier, window and half-dome sizes are drawn from the dome's dimensions and photographs.
Minaret
Weight tower
Half-dome
Pendentive
Thick end wall
Mimar Sinan built the mosque for Suleiman the Magnificent between 1550 and 1557. He took the plan of Hagia Sophia, a central dome with half-domes on the main axis, and made it his own. The dome is about 26.5 metres across and rises 53 metres, twice its width. Its push passes down through the half-domes into thick walls and buttresses, so from outside the building reads as a stepped hill of domes.
Fig. 19b Diagram of half the building. The push of the dome passes into a half-dome, and from the half-dome into the thick end walls and buttresses, stepping down like water over a weir.
Dome pushes out
Half-dome takes it
Walls carry it down
20Edo, 1603 to 1868c. 1615–1660Kyoto, Japan
Katsura Imperial Villa
A house planned in floor mats.
Fig. 20a Plan of the Old, Middle and New Shoin with their mats laid in. One mat is outlined in red. The room sizes in mats follow the published plans; the outline of the halls, the verandas and the moon-viewing platform are simplified.
15 mats
Old Shoin
Middle Shoin
Music room, 3 mats
New Shoin
Moon-viewing platform
Built in stages from about 1615 by Prince Toshihito and then his son Toshitada, the villa's halls are planned in tatami. Every room is named by the number of mats it holds, from three to fifteen, and every mat is the same size, about 1.91 by 0.955 metres in Kyoto. The halls step back across the garden one behind another, raised on posts, with a bamboo platform for watching the moon over the pond.
Fig. 20b Common room sizes. A Kyoto mat is 1.91 by 0.955 metres, twice as long as it is wide, so rooms are named by their mat count. The mats are laid so that no four corners meet.
3 mats
4½ mats
6 mats
8 mats
10 mats
21Mughal, 1526 to 18571632–1653Agra, India
Taj Mahal
Two domes: one for the room, one for the skyline.
Fig. 21a Section through the mausoleum on its plinth, with two minarets beyond. The two domes are in red. The overall height, width, plinth and arch frame are from published figures; the dome profiles, drum and the void between them are drawn from photographs because the sources disagree.
Finial
Outer dome
Hollow between
Inner dome
Main arch frame
Minaret
Shah Jahan began the tomb for his wife Mumtaz Mahal in 1632; the mausoleum was finished in 1648 and the whole complex in 1653, under the architect Ustad Ahmad Lahori. It has two domes. The inner one is sized to the tomb chamber below it. Above it, an empty space and a tall drum lift the outer dome high enough to rule the skyline, 73 metres to the tip of its finial.
Fig. 21b The two domes drawn larger. The inner dome is sized to the tomb chamber below it. The outer dome stands on a tall drum above an empty space, high enough to read across the river and the garden.
Outer dome
Empty space
Drum
Inner dome
22Industrial, 1750 to 18901851London, England
Crystal Palace
A building made in a factory and bolted together.
Fig. 22a The south end of the building, with the arched transept rising above three tiers. Everything is on a 24 ft grid; one bay is outlined in red. The width, grid and transept height are from published figures; the tier heights are estimates.
Arched transept
Ridge-and-furrow roof
Iron and glass
Joseph Paxton, a gardener who built glasshouses, designed the hall for the Great Exhibition of 1851, and it opened within a year of his first sketch. It was made from a few standard parts, cast-iron columns, iron girders and panes of glass 49 by 10 inches, on a 24-foot grid, made in factories and bolted together in Hyde Park. It was 1,848 feet long, needed about 293,000 panes, and was later taken down and rebuilt at Sydenham.
Fig. 22b Section through one bay of roof. The glass is laid in ridges and furrows. Rain runs off the glass into Paxton's timber gutters in the furrows, along to the girder, and down inside the hollow cast-iron columns, which doubled as drainpipes.
Glass ridge and furrow
Paxton gutter
Iron girder
Hollow column
23Industrial, 1750 to 18901884–1885Chicago, USA
Home Insurance Building
A metal frame carries the walls.
Fig. 23a The 138 ft front as built in 1885, with nine storeys at the floor heights published in 1884. On the left, the brick and stone front; on the right, the same front with its walls removed to show the iron frame, in red, that carried them. The bay spacing is an estimate.
Iron columns
Iron beams
Steel beams above
Brick and stone front
William Le Baron Jenney's office building in Chicago, finished in 1885, is often called the first skyscraper. Its two street fronts were carried on a frame of cast-iron columns and wrought-iron beams, with some of the first steel beams in the upper floors, instead of thick masonry walls carrying everything. The frame was said to weigh a third as much as a masonry building. It was demolished in 1931.
Fig. 23b Section through a pier at one floor. A cast-iron column, in red, runs up inside the brick pier. An iron beam rests on a bracket from the column and carries a floor of hollow clay tile. The details are typical of the time rather than measured from this building.
Cast-iron column
Brick pier
Iron beam
Bracket
Hollow tile floor
24Art Nouveau, 1890 to 19141898–1914Santa Coloma de Cervelló, Spain
Colònia Güell church
Hang chains, turn them over, and you have the arches.
Fig. 24a A reconstruction of the idea behind Gaudí's model, about 4 m deep at a scale of 1 to 10. Strings hang from a board on the ceiling and small bags of lead shot stand for the weight each part would carry. The main arch is in red. The string layout is simplified; the original was lost in the Spanish Civil War.
Board fixed to the ceiling
Strings hang into arches
Bags of lead shot
Leaning strings
For the church of a textile workers' colony, Gaudí spent about ten years on a model hung upside down: strings fixed to a board, weighted with bags of lead shot, at a scale of 1 to 10. A hanging string falls into a shape of pure tension; turned over, the same shape carries pure compression. The model found the arches, vaults and leaning columns for him. Only the crypt was built, from 1908, before work stopped in 1914.
Fig. 24b A hanging chain is pulled into a curve where every link is in pure tension. Turned upside down, the same curve stands as an arch in pure compression, with no bending at all. Gaudí's model found the shapes of his arches, vaults and leaning columns this way.
Hanging: pulled
Turned over: pushed
25Sudano-Sahelian, 1300 to now1907Djenné, Mali
Great Mosque of Djenné
A mud building the whole town replasters every year.
Fig. 25a The qibla wall with its three towers, on a platform 3 m above the market square. The red dots are the ends of the palm-wood toron that bristle from the walls. The platform and the central tower are from published figures; the wall height, side towers and buttress spacing are estimates.
Central tower
Buttress pinnacles
Toron ends
Raised platform
The largest mud-brick building in the world stands on a platform about 75 metres square and 3 metres high in the middle of the town. The present mosque was built in 1906 and 1907 by the masons' guild under Ismaila Traoré, from sun-dried mud brick plastered with mud. Rain washes the surface away, so every year the town replasters it together in a festival, the crépissage. The palm-wood sticks that bristle from the walls are permanent scaffolding.
Fig. 25b A section through the mud wall. The toron, in red, stick out about 60 cm and serve as permanent scaffolding: every year the townspeople climb them to spread a fresh coat of mud over the whole building before the rains.
Palm-wood toron
Fresh coat
Sun-dried mud brick
Palm-log roof
26Modernism, 1914 to 19751928–1931Poissy, France
Villa Savoye
Columns carry the house, so the walls go anywhere.
Fig. 26a Elevation of the main front. The upper floor is a box on five thin columns; the glass ground floor sits back in the shadow, and the curved screens of the roof garden rise above.
Thin columns
Ribbon window
Roof garden
Facade hangs free
Glass ground floor
Le Corbusier and Pierre Jeanneret raised the house on thin concrete columns. The columns and floor slabs carry all the weight, so no wall has to. Walls inside can curve wherever the rooms need them, and the outside skin can open into one long window. Underneath, the curved glass wall of the ground floor follows the turning circle of a car. On top, the roof becomes a garden.
Fig. 26b Le Corbusier's Dom-ino frame of 1914, the idea behind the house. Slabs and thin columns, in red, carry everything, so walls and windows can go wherever the plan needs them.
Slab overhangs
Columns carry it all
Stair
27Modernism, 1914 to 19751936–1939Pennsylvania, USA
Fallingwater
Concrete terraces that hang out over a waterfall.
Fig. 27a The house from downstream, with the living-room terrace cantilevered out over the falls; its cantilever is in red. The 15 ft cantilever is from published figures; the rock, falls and floor levels are drawn from photographs.
Cantilevered terrace
Stone chimney core
Pier on the rock
Waterfall
Glass between slabs
Frank Lloyd Wright built the house for the Kaufmann family between 1936 and 1939, over the waterfall rather than facing it. Reinforced concrete terraces cantilever as much as 15 feet from stone piers set on the rock, stacked and turned against each other above the stream. The cantilevers sagged: by 1995 the main terrace had dropped about 7 inches, and in 2002 steel tendons threaded along the beams were tightened to lift and hold it.
Fig. 27b Section along a main beam. By 1995 the tip had sagged about 7 inches (dashed). In 2002 steel tendons, in red, were threaded along the beams and tightened against anchors, lifting the terrace slightly and holding it.
Stone pier
Sag by 1995
Steel tendon, 2002
Concrete beam
28Modernism, 1914 to 19751959–1973Sydney, Australia
Sydney Opera House
Every shell is cut from one sphere.
Fig. 28a The shells from the west, on their podium above the harbour. Every edge is drawn as an arc of the same 75.2 m radius; the leading edge of the tallest shell is in red. The length and the height of the tallest shell are from published figures; the other shell sizes and the podium height are estimates.
Tallest shell
Precast ribs fan out
Podium
Harbour
Jørn Utzon won the competition in 1957 with sketches of white shells that no one yet knew how to build. The answer, after years of work with the engineers Ove Arup and Partners, was to cut every shell from the surface of one sphere, 75.2 metres in radius. Because each curve was the same, the ribs could be cast in standard concrete pieces and covered in a little over a million tiles. Construction ran from 1959 to 1973; Utzon left in 1966 and never saw it finished.
Fig. 28b The solution Utzon found in 1961: every shell is a curved triangle cut from the surface of one sphere of radius 75.2 m. Because every curve is the same, the ribs could be cast in standard pieces and the tiles laid in repeating panels.
Shells cut from it
One sphere
29Contemporary, 1975 to now1971–1977Paris, France
Centre Pompidou
The pipes and stairs move outside.
Fig. 29a Section across the building. Each 45 m floor truss rests on cast-steel gerberettes that pivot on the columns; the outer ends are tied down. The services, in red, run up the outside: the ducts on the east side and the escalator tube on the west. The truss depth and duct sizes are estimates.
Floor truss
Gerberette on column
Ducts outside
Escalator tube
Tie rod
Renzo Piano and Richard Rogers, with the engineer Peter Rice, won the competition in 1971 with a building turned inside out. The steel frame, the ducts, pipes and wiring, and the escalators all sit on the outside, colour-coded by what they carry, so each floor inside is a clear space 45 metres wide and 166 metres long. Cast-steel brackets called gerberettes balance the floor trusses on the columns. It opened in 1977.
Fig. 29b One gerberette, a cast-steel bracket 8 m long, in red. It pivots on a pin through the column. The floor truss presses down on the short inner arm, and a tie rod pulls down the long outer arm, so the two balance and the column takes the weight straight down.
Truss load
Pin on the column
Cast steel
Tie rod
30Contemporary, 1975 to now1993–1997Bilbao, Spain
Guggenheim Bilbao
Software from aircraft design makes the curves buildable.
Fig. 30a The museum from across the river, with the long gallery running east under the bridge. One curved volume is outlined in red. The 130 m gallery is from published figures; the height and the curves are drawn from photographs, since no measured elevation was found.
Titanium over steel
Long gallery
Bridge
River
Frank Gehry's museum, opened in 1997, is clad in about 33,000 titanium panels, each less than half a millimetre thick, over curves no drawing board could describe. His office used CATIA, software made by Dassault Systèmes for designing aircraft, to model the shapes, check the structure and cut every panel and steel member to fit. Its effect on the city gave a name to culture-led regeneration: the Bilbao effect.
Fig. 30b A patch of curved skin as modelled in CATIA, software first written for aircraft. The computer described every curve exactly, so each titanium panel, in red, could be unfolded into a flat shape and cut to fit before it reached the site.