Arch

ARCH 1.

2. 3.

A structure, especially one of masonry, forming the curved, pointed, or flat upper edge of an open space and supporting the weight above it, as in a bridge or doorway. A structure, such as a freestanding monument, shaped like an inverted U. A curve with the ends down and the middle up: the arch of a raised eyebrow.

semicircular arch

A. keystone B. voussoirs

1. Keystone 2. Voussoir 3. Back 4. Impost 5. Intrados 6. Rise 7. Clear span, "Bay" 8. Abutment

Natural arches

Fort D efia nce, Ar izon a . Bla ck R ock Na tura l Br id ge

Bl ack Moun tain W ash a few mil es west of M an y F ar ms, Ar izo na

Na vaj o l and i n Red Val ley, A rizon a

Types of arches La nce t a rch

Tria ngu la r a rch

Round ar ch

Segme ntal a rch

Unequal round arch

Shou ld ered f lat ar ch Horseshoe arch

Three-foiled cusped arch

Three-centered arch

Elliptical arch

Inflexed arch

Ogee arch

Tudor arch

Parabolic arch

Reverse ogee arch