Type of arch with a circular arc of less than 180 degrees
A segmental arch.
A segmental arch is a type of arch with a circular arc of less than 180 degrees.[1] It is sometimes also called a scheme arch.[2]
The segmental arch is one of the strongest arches because it is able to resist thrust.[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. Segmental arches with a rise that is less than one-eighth of the span width must have a permanent support or frame beneath the arch to prevent failure.[3]