Architecture: from Karnak to Florence

chris cambré, Feb 8, 2017

Around the year 1000 florishing abbeys and pilgrim routes to Rome and Compostella gave western building activities a strong boost. The history of medieval architecture can be read as one long search for an answer to the question 'how to build nice and large churches?' Local teams of stone workers and wood carvers haven't got a theoretical knowledge of the basic principles of stability. A church that falls down is built again in another way. A solution that's not nice isn't repeated. Arised by experiece regional schools devellop their own forms and technical solutions. Starting with examples from Classical Antiquity we will illustrate the basic principles of stability and spanning in this GeoGebrabook. Then we will follow the medieval story from the earlier romanesque experiments to the spactacular gotic cathedrals. 400 year later Filippo Brunelleschi is a new game changer. In the dome of the Florence cathedral he still uses the pescribed gotic forms. But the common knowledge of a group of craftsmen is no longer the dominating factor in the building proces. This common knowledge is replaced by the geniality of the artist. So Brunelleschi marks as well the end of the gotic area as the beginning of renaissance. Follow the story of bending joists, circular and pointed arcs in an architectural journey through time.

Table of Contents

  1. Classical Antiquity
    1. Greek architraves
    2. Karnak: a forest of colums
    3. Roman circular arcs
    4. horizontal forces
    5. from a circular arc to a barrel vault
    6. from a barrel vault to a groined vault
    7. from a circular arc to a dome
    8. domes and half domes in the Aya Sofia
    9. how to support a spherical dome?
    10. dome with cantilever construction
    11. dome with pendentives
  2. romanesque architecture
    1. stone vaults
    2. thick walls with little openings
    3. from a circular to a pointed arc
    4. pointed barrel vault
    5. elevating the nave
    6. groined vault
    7. adjacent groined vaults
  3. alternative solutions
    1. building domes
    2. crosswise placed barrel vaults in Tournus
  4. gotic architecture
    1. the gotic pointed arc
    2. the problem of the diagonal
    3. a circular diagonal
    4. circular diagonal, pointed barrel vault
    5. leaving the square base
    6. from supporting walls to a skeleton
  5. the dome of Brunelleschi
    1. a new church
    2. a pointed dome
    3. a pointed dome (2)
    4. ingenious solutions
    5. the brickwork of the dome

1.

Classical Antiquity

How did Egyptians and Greek construct theis builings and what was the revolutionary aspect of the Roman vaults?

  • 1. Greek architraves
  • 2. Karnak: a forest of colums
  • 3. Roman circular arcs
  • 4. horizontal forces
  • 5. from a circular arc to a barrel vault
  • 6. from a barrel vault to a groined vault
  • 7. from a circular arc to a dome
  • 8. domes and half domes in the Aya Sofia
  • 9. how to support a spherical dome?
  • 10. dome with cantilever construction
  • 11. dome with pendentives

1.1.

Greek architraves

architraves
In constructing their temples Greeks used [b]architraved[/b]: horizontal joistsare supported by colums.
pressure and traction
When loaded a joist, supported in two points, will bend. The upper part will come under pressure, the lower part will come under traction. Stone can support very high pressure, but when it comes to traction resistance is reduced to 1/10th.[br]To reduce traction in a joist you just have two options:[br][list][*]You can use a larger joist.[/*][*]You can reduce the span.[/*][/list]
Parthenon
Het Parthenon is 30,9 m breed. Deze afmeting kan je onmogelijk overbruggen met één marmeren balk. De Grieken konden niet anders dan bijkomende zuilen plaatsen en de tempelbreedte verdelen in kleinere overspanningen.
– chris cambré

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2.

romanesque architecture

  • 1. stone vaults
  • 2. thick walls with little openings
  • 3. from a circular to a pointed arc
  • 4. pointed barrel vault
  • 5. elevating the nave
  • 6. groined vault
  • 7. adjacent groined vaults

2.1.

stone vaults

stone vaults
Around 1000 florishinf abbeys and pelgrimroutes to Rome and Compostella gave Western architecture a boost. Especially the French region of Bourgondy became a lab for innovations in the evolution of what was to be called the romanesuqe style later on.[br]One of the prominent characteristics is the use of stone vaults. These vaults were a step forward compared to wooden ceilings. They offered a better protection against rain, snow, wind and fire, often caused by a bolt of lightning.
construction
The barrel vault is derived from the circular arc. The stone vaults were constructed upon a wooden folding. When finished this folding could be removed since a circular arc and a barrel vaults are self supporting.
– chris cambré

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3.

alternative solutions

The evolution of romanesque architecture is not a straight line. Alternative solutions were raised, but did not survive.

  • 1. building domes
  • 2. crosswise placed barrel vaults in Tournus

3.1.

building domes

In the beginning of the 12th century churches with domes were built in western France (Angoulême, Périgueux, Fontevraud and Poitiers). These may be influenced by trading relations with Venice. Building spherical domes on cubical bases is a way to create large spaces.[br]In the evolution of medieval architecture this solution wasn't to be followed.
interior and plan of the Angoulême cathedral (1120-1130)
exterieor and plan of the Périgueux cathedral (from 1120)
– chris cambré

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4.

gotic architecture

  • 1. the gotic pointed arc
  • 2. the problem of the diagonal
  • 3. a circular diagonal
  • 4. circular diagonal, pointed barrel vault
  • 5. leaving the square base
  • 6. from supporting walls to a skeleton

4.1.

the gotic pointed arc

The pointed arc appeared even in romanesque architecture, but it's a main feature in gotic style. In a [i]normal gotic pointed arc[/i] the midpoints of the two circular arcs are replaced from the centre of the window unto the corners of it. In the pointed arc you can draw a equilateral triangle.[br][b]Drag the green point in the applet to the left[/b].
width of the wall
By verticalizing the vault, one could economise on the width of the wall.
– chris cambré

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5.

the dome of Brunelleschi

  • 1. a new church
  • 2. a pointed dome
  • 3. a pointed dome (2)
  • 4. ingenious solutions
  • 5. the brickwork of the dome

5.1.

a new church

an ambitious plan
By the end of the 13th century the ambitious republic of the town of Florence thought about a new church with much more prestige than the current Santa Reparata. Arnolfo di Cambio got appointd for the job.[br]The government approved a typical gotic plan with nave, side aisles, transept and crossing, but with gigantic dimensions as e.g. a lenght of 153 m. It's just while standing high above the nave at the foot of the dome you get the right experience of the dimesion of the chruch.
the dome
But the most ambitious part of the plan was of course the octogonal dome that was planned above the crossing.
How to continue?
In the midst of the 14th century the building proes stopped. The form and the dimensions of the dome were fixed, but nobody had just an idea how to realise such a great dome. Between 1410 and 1413 the drum was built (the octogonal prisma to support the dome), but again no-one could think of a solution for the dome.
– chris cambré

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Information