Catenary arch

A catenary arch is a type of architectural pointed arch that follows an inverted catenary curve. It is common in cathedrals and in Gothic arches used in Gothic architecture. It is not a parabolic arch.

The 17th-century scientist Robert Hooke wrote, "Ut pendet continuum flexile, sic stabit contiguum rigidum inversum", or, "As hangs a flexible cable so, inverted, stand the touching pieces of an arch."

A note written by Thomas Jefferson in 1788 reads, "I have lately received from Italy a treatise on the equilibrium of arches, by the Abbé Mascheroni. It appears to be a very scientifical work. I have not yet had time to engage in it; but I find that the conclusions of his demonstrations are, that every part of the catenary is in perfect equilibrium".

What makes the catenary arch important is its ability to withstand weight. For an arch of uniform density and thickness, supporting only its own weight, the catenary is the ideal curve.

This is done by a catenary curve: Catenary arches are strong, as they redirect the vertical force of gravity into compression forces pressing along the arch's curve. In a uniformly loaded catenary arch, the line of thrust runs through its center.

Rainbow Natural Bridge in the U.S. state of Utah has a natural catenary shape, possibly produced by weathering in high-stress areas.Kolob Arch and Landscape Arch, also in Utah, have a catenary shape as well.

The Gateway Arch in the American city of Saint Louis, Missouri.

Due to aspect ratio, the top being thinner than the bottom, its actual shape is technically a "weighted catenary".

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