Part 2: Efficient Engineering Innovations

There were many specific breakthroughs in the field of architectural engineering during this period of the Middle Ages. These breakthroughs, though some of them did nothing more than increase building efficiency and safety, are also associated with the beauty inherent in the Gothic style. Many of these innovations, in fact, came about as architects and engineers became more and more daring, making ceilings higher and higher, expanses wider and wider, all to evoke feelings of grandness and awe in visitors.

The first of these, and the one most important to this goal is the rib vault, a form of ceiling construction. Now, to understand why the invention of the rib vault is significant, one must compare it to its Romanesque predecessor, the barrel vault or groin vault. Barrel vaults, much like their namesake, are shaped like a barrel. They are nothing more than a domed ceiling, sometimes supported by periodic arches. This is all well and good, but has a severe limitation. Barrel vaults are limited in height and width by simple physics. If the stones are correctly mortared together and the ceiling is in one piece, all that mass in the dome places the walls under high stress, pushing them outwards. The larger the ceiling, the thicker and stronger the walls need to be, adding tremendous expense to the construction.

 

In a basic barrel vault (left) the forces from the heavy ceiling push the walls outward. It works, but you need very thick walls, like this Romanesque cathedral in Rome (right).

The advent of the rib vault solved this puzzling ceiling weight problem. The ribs are of stone, arching and crossing back and forth through the ceiling’s expanse. The ceiling itself is composed of much thinner stone plates. No longer do the architects need to lift prohibitively enormous stone bricks so far up. The ribs hold these panels up with little to no trouble, since the weight of the ceiling is now supported along the ribs instead of by the walls. In addition, rib vaults tend to have more pointed inner arches rather than a semicircular dome. This also carries the weight of the ceiling more evenly, in many directions instead of one or two.

 

The final piece of the puzzle, easily remedied, is the support of the ribs themselves. Piers attached to the walls carry the force from the ribs down through the piers. This architectural choice is twofold: first, it allows for slightly thinner walls, since the piers take the ceiling’s weight, not the whole wall. As discussed later, this is also an important decision where stone transportation is concerned. In addition, since the piers are small relative to the wall’s area, this leaves the wall space open for other ornaments, any kind of art befitting the building.

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Rib vault in the Basilica of St. Denis in Paris. The columns in the center and against the walls carry the force of the ceiling ribs. Also note the several pointed arches in the ceiling. The columns leave plenty of room for the stained-glass arched windows.

The second primary innovation in Gothic architecture is the flying buttress. Now, buttressing was a common method of support since antiquity and before, but this variation of buttressing solves the specific problems medieval architects faced, correcting the outer-wall equivalents of the inner-wall and ceiling issues.

A buttress supports a wall by arranging material in such a way that a section of wall is leaning partially on it. Buttresses are used for initial support- i.e. knowing that a wall needs them, as well as replacement, if a wall is in danger of collapsing. Flying buttresses are unique in that unlike traditional buttressing, the whole flying buttress is not in contact with the wall. Instead, an arch is attached from the wall to an outside pier. Because the arch is what transfers the outward force of the wall down through the pier, and the arch is suspended in the air between the two points, it appears to be flying. Hence the name ‘flying buttress.’ Just like the rib vault, the flying buttress opened up the walls to allow for increased display of art, and as a result, beautifully ornate facades and pointed, arched windows greet visitors to the many Gothic cathedrals around Europe.

In a basic flying buttress (left), the wall is only supported by a thin, “flying” arch. The force travels down through the arch into a separate column, as in this example from the Chartres Cathedral (right).

Far from being the Dark Ages, the high medieval era was a period of vibrancy and incredible art. As sculptors and artists completed work after work, the masons, a different kind of artist, plied their own trade to build some of the most beautiful buildings ever made, despite little to no knowledge of modern engineering principles. The result of their labor certainly commands our respect today.

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