Segmental arch

[3][clarification needed] To prevent failure, a segmental arch must have a rise that is equal to at least one-eighth the width of the span.

[3] The segmental arch is very old (the versions were cut in the rock in Ancient Egypt c. 2100 BC at Beni Hasan).

Since then it was occasionally used in Greek temples,[4] utilized in Roman residential construction,[5] Islamic architecture, and got popular as window pediments during the Renaissance.

[4] The closed-spandrel Pont-Saint-Martin bridge in the Aosta Valley in Italy dates to 25 BC.

[8] Some use continued, in the 20th century mostly in residential construction over doorways, fireplaces, and windows.