Glossary · P
Pointed arch
Also called ogival arch
An arch of two arcs meeting at an apex; equilateral when each is struck from the opposite springing, lancet when sharper, drop when blunter.
See also: Lancet, Equilateral arch
Rules that use the word
How the pointed arches are drawn. Draw a pointed arch from two centres on the springing line. With the centres at the springings, the arch is equilateral; with centres beyond them, a lancet; with centres between them, a drop arch. Late Gothic added arches of four centres and the reversed curve of the ogee.
Pointed arches reach any height on any span. A round arch must rise half its span, so arches of different spans on one springing line have crowns at different heights. A pointed arch can be given any rise at least half its span, so arches of different widths can all be made to reach the same height.
The problem of the oblong bay. Two semicircular barrels of different spans rise to different heights. To groin-vault an oblong bay the narrower barrel must be stilted or flattened, and the groins then wander out of plane: the difficulty that pushed builders towards ribs and pointed arches.
Level crowns over an oblong bay. Over an oblong bay, make the diagonal ribs semicircular and strike the transverse and wall arches as pointed arches of the heights needed to bring every crown nearly level with the central boss.
Where it appears in the book
In the chapters The Arch, Vaults, Romanesque and Gothic.
A feature of Early Islamic (Umayyad and Abbasid), Persian Islamic (Seljuk, Timurid and Safavid), Gothic, Gothic Revival architecture.
Nearby in the glossary
Pleaching · Plinth · Poché · Podium · Pointed architecture · Polygonal masonry · Polylobed arch · Porch