FLORENCE CATHEDRAL ITALY ( 14 – 17 century )Brunelleschi’s dome / Duomo.Presentation by Ketki Darp B.V.D.U.COA ,Pune fourth year B.arch semester VII

( 1377 – 1446 )

Principal architect apart from Arnalfo di cambio .Brunelleschi’s dome is the largest masonary dome ever built, tallest untill St.peter’s church was built and is the coverage of florence. (structure of the dome is very imposing )

Total length of cathedral 153mHeight 114.5mMaterials used - marble , brick

The dome is 45m wideThe impost rising to a height of 35.50m which is about 54 m above ground level.

Architectural style Gothic - Renaissance .Exedrae / blind tribunes added around the outside of the dome look very classical compared to the gothic church .Also refers back to the Tuscan Romanesque tradition in terms of polychromy , the colored marbles , which he also carries up into the The barrel just below the dome itself.

Filippo Brunelleschi

Influenced from the Pantheon of rome which is equal in width to the cathedral’s dome. But the technology used in ancient world had been lost, so the dome is only the result of the amazing engineering of Brunelleschi.

The dome of Pantheon is a single shell of concrete and is hemispherical unlike the cathedral’s dome.

Brunelleschi’s dome was a challenge to build a dome without centering . A dome is really just an arch which is supported by the wooden frame work until l it can be locked in place by the keystone.The problem with the cathedral ‘s dome was that they could’nt get enough lumber , that was strong enough to hold the structure. So, they could’nt do wooden scaffolding or centering to hold it up. A dome exerts pressure not only down but down and out, so the biggest challenge was to deal with downward and outward pressure not cracking the walls underneath. In old times, in case Pantheon they dealt with it by just creating sheer bulk that is 10 feet thick walls but it could not be done in case of cathedral due to less thickness of walls.

Direction of thrust

10 Feet thick walls.

Pantheon of rome

Cathedral’s dome

Skeletal Structure Of The Dome

•First decision was to make the dome as light as possible ( double shell structure ).•It had ribs which are doing a lot of weight bearing. Besides the major rib visible from out side there are two within which can’t be seen from outside and those are actually locked in place by a series of horizontal ribs as well.•A system was developed as the dome was being raised up, each course of stone and brick added actually locked itself in place.•Thus creating a self sustaining dome.

Main rib

•In order to deal with downward and outward thrust - creation of chains inside the dome made out of stone and wood locked together with iron to hold the dome. Eg- An old fashioned wooden barrel that has iron rings around it to keep the wood together.

Wooden barrels

•The revolutionary method improvised using herringbone masonary by which bricks were laid sloping inward and was accomplished by the team of masons moving around the perimeter in succcessive rings.

•About 4 million bricks were used in its construction and estimated weight of the dome is 37000 tons.

Herring bone masonary used in the dome

Stages Of Construction Of Dome

Inner view of the dome

A tall , pointed dome soaring high in the sky.Morover what Brunelleschi did , he did without having an example to lean

on , an utter invention.

“The abiding memory will be the way the rhythmn of tiled roofs culminates triumphantly in the great dome”.

Thankyou….