The dome of the Florence Cathedral took over 100 years to complete. Filippo Brunelleschi was tasked with finishing the dome in the early 15th century. He designed an octagonal dome without external supports, using advanced structural innovations like horizontal chains and pointed ribs. His dome spanned 140 feet, the largest at the time. Through special lifting machines he invented, Brunelleschi was able to hoist over 4 million bricks to complete the massive 114.5 meter tall dome, cementing his role as a pioneer of Renaissance architecture.

1. Ÿ The beginning of the fifteenth century, after a hundred years of construction, the
structure was still missing its dome. The basic features of the dome had been designed
by Arnolfo di Cambioin 1296.
Dome Of Florence Cathedral
Ÿ Filippo Brunelleschi, the first great architect of the Renaissance, worked primarily in
churches. His most famous masterpiece is the octagonal brick dome he designed
for Florence Basilica (an Italian Gothic church), an engineering feat of such difficulty
(due to the dome's unprecedented size) that he also had to invent special machines to
hoist each section into place.
Ÿ This dome is the most famous transitional work
between Medieval and Renaissance architecture
Cathedralofsantamaria
Ÿ Although at first glance it appears to be very much
a Gothic dome (given its pointed shape and ribbed
frame)5, it is considered a transitional work due to
Brunelleschi's attention to balanced proportions
and simple decoration. It is crowned by a lantern,
a rooftop structure with openings for lighting or
ventilation.
Ÿ Is an octagonal dome higher and wider than any
that had ever been built, with no external buttresses
to keep it from spreading and falling under its own
weight.
Ÿ The drum or base of the dome was already in place
before Brunelleschi received the assignment to
complete it.
Ÿ The span of the octagonal drum was 140 feet, a
very large span for a dome at that time, especially
one without the possibility of external buttressing or
supports.
Ÿ Brunelleschi knew that a hemispheric dome (one
which is perfectly rounded) would not be able to
span this distance without the use of external
buttresses.
Ÿ As a result, he decided to make a pointed dome.
He placed 8 major ribs at the points of the octagon,
and 16 minor ribs (two in the space between every
two major ribs), all tied together by lateral bands.
Dipesh B. Makwana
14SA207

2. Ÿ The spreading problem was solved by a set of four internal horizontal stone and iron
chains, serving as barrel hoops, embedded within the inner dome: one each at the top
and bottom, with the remaining two evenly spaced between them. A fifth chain, made
of wood, was placed between the first and second of the stone chains. Since the dome
was octagonal rather than round, a simple chain, squeezing the dome like a barrel
hoop, would have put all its pressure on the eight corners of the dome. The chains
needed to be rigid octagons, stiff enough to hold their shape, so as not to deform the
dome as they held it together.
Ÿ To lift 37,000 tons of material, including over 4 million bricks, he invented hoisting
machines and lewissons for hoisting large stones. These specially designed machines
and his structural innovations were Brunelleschi's chief contribution to architecture.
Ÿ The lantern was finally completed by Brunelleschi's friend Michelozzo in 1461. The
conical roof was crowned with a gilt copper ball and cross, containing holy relics,
by Verrocchio in 1469. This brings the total height of the dome and lantern to 114.5
metres (375 ft).
Ÿ Brunelleschi’s design features a double-walled ovoid shell anchored at the bottom by a
15 meter high tambour eliminating the need for scaffolding and reinforcement. The
dome is 44 meters in diameter and 113 meters high topped by a lantern that is
accessed by a stairway between the interior and exterior walls of the dome. Florence
Cathedral is commonly known simply as The Duomo because of the beauty and
magnificence of Brunelleschi's design and its striking impact on the skyline of Florence
Dipesh B. Makwana
14SA207