What can modern engineering learn from an erstwhile jeweler who built the largest masonry dome in existence?
The researchers said the results could be especially useful in cases where remote construction, by drone for example, could be done with minimal temporary supports.
The specific structure that the team studied was Santa Maria, in Ciel d’Oro, of Montefiascone, Italy. The crux of their analysis rests on the geometrical pattern of bricks used throughout the interior dome, which appears to be the lynchpin vital in making the structure self-supporting. The bricks form a herringbone, a V-shaped pattern, between the horizontal field bricks and vertical bricks at the beginning and end of the horizontal rows. The arrangement creates lines of staggered vertical bricks that extend diagonally across the curvature of the dome.
The arrangement produced is a complex cross-herringbone spiraling pattern. One herringbone from both the left and right angles repeatedly cross each other, providing stability for the interior bricks and maintaining the dome’s curvature. The researchers’ analysis showed essentially that this is a double-helix of support that distributes and equalizes weight and thrust within the structure. This system of cross-herringbone veins is known as a double loxodrome.
The simple yet ingenious physics exhibited by the structure “is an elementary act that transforms the amorphous and inert material into a sign of life that [motivates] the tensions between opposing forces and composes them in their equilibrium,” said Pizzigoni. Italian renaissance domes are an architectural form that “recognizes the disciplinary complexity” of blending the ideals of “stability, beauty, and utility, that runs between engineering, construction, and architecture.