This is my summary of what I learned from reading Brunelleschi's Dome, by Ross King.
First of all, it is beyond the comprehension of our fast-fashion, self-absorbed, materialistic world that designers, architects, and artisans would invest their entire lives in projects they would not live to see completed. Leaders would commission works intended to last for centuries that would likely not be completed in their lifetime, either. These works were meant to be for the good of the city, not a single person's legacy. Giotto's tower took over 200 years to complete. The wall around Florence took 50 years.
When Florence was under threat from a cruel authoritarian from Milan, Giangaleazzo Visconti, they commissioned a competition for new bronze baptistry doors that were to visualize Abraham's sacrifice of Isaac. Some surmise that they were seeking a similar "sudden salvation from mortal threat" with this work. Their view of “sudden” is much different than ours. They gave the competitors an entire year just to produce their samples, all while an enemy threat was looming.
In the 13th century, Florence had become prosperous in the textile trade and banking. You’ve probably heard of the famous wealthy Medici family, who ran the banks. Florence was also known for their wool trade. The wool merchants commissioned, under the organization of “Opera del Duomo,” the construction of The Cathedral of Santa Maria del Fiore. It was intended to make a statement of the great power of Florence and was to be the largest dome ever built, dwarfing the Pantheon.
Construction began in the year 1296. I have to precede that with “the year” because 1296 is so long ago it doesn’t even register as a place in time for us. The original architect, Arnolfo di Cambio, died soon after construction began. He had built a scale model of the cathedral (quite sizeable at 30’) but did not have specific plans as to *how* the full-size massive dome would be constructed. He trusted that God, or new technology, would provide the way to construct it. Ironically, his scale model collapsed sometime in the 1300s, but construction faithfully continued.
Years later, Neri di Fioravanti, a mason, proposed an 8-sided dome, that was more pointed instead of just a semi-circle. He also insisted that it not be supported with exterior buttresses, deemed unsightly. He built another scale model in 1367, and then died in 1372. Every year, on January 1, workers would take an oath to build the cathedral according to the model he constructed.
In 1418, a full 122 years after construction began, the Opera called for another competition for someone to bring plans to construct the dome. Filippo Brunelleschi was a goldsmith who had a knack for the art of watchmaking and mechanics. It is said that he created the first alarm clock.
At the time, domes were usually built by “centering,” or creating a wooden scaffolding in the shape of the dome and placing the bricks on top. When the dome was finished, the scaffolding would be removed. There were certain disadvantages to this system, notably that the wood would settle and shrink a bit over time, causing the dome to be slightly off originally calculations.
"I do not know if even ancient builders ever vaulted so awesome a space [...], but, calling to mind that this temple is sacred to God and to the Virgin, I am confident that, since it is all done in memory of Him, He will not fail to instil knowledge where it is lacking and to increase the force and inventiveness of the man called to create such a structure" —Filippo Brunelleschi
Filippo argued against that method and convinced the opera that he could do it without “centering.” Though understandably skeptical, he ultimately convinced them, but they were cautious enough to write in the contract that after the dome had reached a certain height, they would reevaluate. “Because in building only practical experience will teach that which is to be followed.“ Again, it is amazing to me how willing they are to experiment with such massive projects. The whole thing could’ve crumbled and cause them to start over from the beginning. It may have delayed the project another hundred years! Page 53.
This video gives a great overview of how he did it. At 2:08 you see the herringbone brick technique, but the image is flat, so you may not realize that the vertical "bookend" bricks function to lock in the horizontal bricks between them because they are all slightly leaning inward toward the curve of the dome, thus pinching the horizontal bricks between them. It creates another miniature self-supporting arch between each course of vertical bricks. Repeat those mini arches all the way around each layer of the dome and the dome is self-supported even during construction. GENIUS.
In 1436, 140 years after starting construction, the dome was finally completed and consecrated. Now there was a whole new effort to design and build the lantern on top. Ugh. I’m tired just thinking about it. STILL not finished?
Filippo also designed and engineered the work for the lantern on top. For reference, this is no small lantern. It has windows that are 30 feet high! The bronze ball on top of it all has an openable door where you could look out over the city of Florence from a height of 350 feet. The entire lantern weighs 1,000,000 pounds! Brunelleschi really trusted the strength of that dome. P144
The general public were also alarmed at putting something so heavy on top of the dome. But Filippo said that it would actually strengthen the dome by acting as a keystone. P147
And I guess after almost 600 years, we can say he was right.
Now, here is…the rest of the story. Paolo Toscanelli met Brunelleschi in 1425. He was trained as a physician, but spent most of his life as a mathematician and astronomer. He recognized the unique opportunities such a tall structure provided for astronomical observations. He installed a plate of brass with a small hole at the top of the dome that passed a small ray of light to the floor of the Cathedral 300 feet below. It acted as a sundial that tracked the movement of the sun and gave very accurate information on the solstice and equinox. P148
His observations allowed him to make corrections to sea navigation methods and gave him reason to suppose that the east Indies could be accessed by navigating the waters to the west instead of overland. He was unable to convince the king of Portugal of such an endeavor. But an ambitious explorer known as Christopher Columbus saw his letter to the king and was inspired. Columbus opened a correspondence with Toscanelli to discuss the details. After he also was denied funding from Portugal, he petition King Ferdinand and Queen Isabella of Spain in 1486. P150–151
You know the rest.
Fun facts:
You may be familiar with the principle of the vanishing point in two-dimensional art. Brunelleschi is the first to apply that principle to architecture, giving the illusion of making things appear even taller by narrowing the features at the top.
Because there was no interior wooden scaffolding, the masons had to work at increasingly steep angles to lay the brick. This was a bit nerve-racking. Filippo pacified their concerns by building a scaffolding below the chasm to act as a safety net, but also covered with a large canvas, mostly to prevent them from looking down and realizing how high they were. They were also required to dilute their wine with water. They didn’t want anyone getting too tipsy. “Only” one person fell to his death during construction, which historically was a pretty good record. P95-96
Filippo had enough foresight to plan ahead for the work of painting the interior of the dome with Frescos. He installed iron rings into the brickwork upon which platforms could be hung for the painter to work! P161
He also installed two different stairwells for workers to ascend to their work every day. The equivalent of climbing a 40 story building every day. There was one set of stairs for workers to go up and a different one to go down so that they didn’t bump into each other. And the ones to go down spiraled counter clockwise first, and then finished clockwise, apparently so as to not dizzy them on the way down, graciously accommodating for their weariness at the end of the day. P161
Comments
Post a Comment