Filippo Brunelleschi – The Man Behind Construction Of The World’s Largest Masonry Dome

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Brunelleschi began his architectural career in 1404 when he acted as an advisor for the Santa Maria Novella, but his involvement with the dome for the Santa Maria del Fiore in Florence marked his first foray as a practicing architect. He worked on this project off and on from 1417 until 1434. All of Brunelleschi’s works indicate that he possessed inventiveness as both an engineer and as an architect.

Brunelleschi was the first architect to employ mathematical perspective to redefine Gothic and Romanesque space and to establish new rules of proportioning and symmetry. Although Brunelleschi was considered the primary initiator of stylistic changes in Renaissance architecture, critics no longer think him the “Father of the Renaissance.”  He is perhaps most famous for his development of linear perspective and for engineering the dome of the Florence Cathedral, but his accomplishments also include other architectural works, sculpture, mathematics, engineering and even ship design. His principal surviving works are found in Florence, Italy.

From his training in the gothic or medieval manner to the new classicism in architecture and urbanism that we now loosely call the Renaissance and of which Brunelleschi is considered the seminal figure. Brunelleschi’s first architectural commission was the Ospedale degli Innocenti (1419–ca.1445), or Foundling Hospital. Its long loggia would have been a rare sight in the close and curving streets of Florence.

While Gothic in spirit the proposed building was different than its northern counterparts in that it’s design included a large octagon dome higher and broader than any that had ever built. The Florentines also did not want to use buttresses as in the style of their northern enemies. However, the biggest problem was nobody knew how to build a dome that large.

Santa Maria del Fiore was the new cathedral of the city,  Because the city fathers forbade buttresses, and because it was impossible to obtain rafters for scaffolding long and robust enough (and in sufficient quantity) for the task, it was unclear how a dome of that size could be constructed without it collapsing under its weight. Also, the stresses of compression were not clearly understood, and the mortars used in the period would set only after several days, keeping the strain on the scaffolding for a very long time. He invented the new hoisting machine for raising the masonry needed for the dome, a task no doubt inspired by the republication of Vitruvius’ De Architectura, which describes Roman mechanisms used in the first century AD to build large structures such as the Pantheon and the Baths of Diocletian.

Brunelleschi is famous for two-panel paintings illustrating geometric optical linear perspective made in the early 1400s. He schemed to build an inner hemispherical dome within Florence cathedral’s octagonal drum. A second, thinner ovoid brick dome was placed on top served as a protective covering from the elements. Nine sandstone rings would then hold the structure together, like a barrel thereby counteracting the downward and outward thrust forces that could cause the dome to collapse.

Brunelleschi still had to construct the dome without any interior scaffolding. His ingenious solution was to lay up the brick shell of the dome in a diagonal herringbone pattern. In this way, the forces in self-supporting rising shell were passed down through as if through an interlocking web. To lift 37,000 tons of material, including over 4 million bricks and sandstone beams several hundred feet in the air, Brunelleschi invented a fast and efficient hoist with the world’s first reverse gear, allowing an ox to raise or lower a load at the flick of a switch. He also was issued one of the first patents for the hoist in an attempt to prevent theft of his ideas.

The work, begun in the summer of 1420, was finished – except for the lantern on top – by 1436. The Cathedral dome of Florence also marks a transition to reliance on technological innovation to overcome the restraining bonds of the natural world. Brunelleschi’s triumph also contains the seeds of what have become the expected personality traits of the designer/engineer: secretive, difficult, controlling, loner, isolated decision making, egocentric, genius.

Brunelleschi observed that with a fixed single point of view, parallel lines appear to converge at a single point in the distance.

The Reinvention of Linear Perspective with these principles, one can paint or draw using a single vanishing point, toward which all lines on the same plane appear to converge. The dome: 45m (148 feet) wide and 90m (295 feet) high from drum to the top of the lantern (rising to a total of 114.5m, or 375 feet, feet off the ground), with no pile of dirt or forests of scaffolding to support it, and—far from collapsing under its own weight—the dome stands to this day, rising nobly above the city skyline as the symbol of Florence. He used vertical marble ribs to distribute the load, wrapping the inner wall with sandstone and chain “barrel hoops” between the ribs to prevent them from spreading. He built the dome not as one piece but of two shells, an inner and an outer one, each thinning as they approached each other and the top.

The workers still needed something to stand on while they laid all that brick, of course. So Brunelleschi directly incorporated hooks, holes, and rings into his design so that small, movable sections of scaffolding could be hung from completed parts of the dome, enabling his crew to work on the next segment up.

Brunelleschi didn’t merely design an impressively large (and quite beautiful) dome. In the process, he also made massive advances in engineering, created dozens of suddenly indispensable tools and machines, and revolutionized the Renaissance construction industry.

For his efforts, Filippo Brunelleschi was according to a singular honor. He remains the only Florentine ever buried in the cathedral itself—directly below his revolutionary dome. It’s an icon shrouded in mystery because no one knows exactly how it was built. It is in a shape of a pointed arch with 8 points rising to a central point crowned by a huge marble lantern. It is two domes one inside the other. Inner dome span – 150feet height – 108feet. Bricks were oriented in spina- pesce (fishbone)  or herringbone which increases the strength (mortar weakness ). He incorporated the flower in his workplace of  model . As we move the rope around the flower, it transfers the curve to the wall with this technique all arches meet at the same point. By 1300 gothic cathedrals were using arches and vaults

Only the artist, not the fool Discovers that which nature hides.

 

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