Triangular arch

File:Refugi pedra Tales.jpg

In architecture, a triangular arch (sometimes angular arch{{sfn|Audsley|Audsley|1881|p=37}}) typically defines an arch where the intrados (inner surface of an arch) consists of two straight segments formed by two stone slabs leaning against each other.{{sfn | Woodman | Bloom | 2003 | loc=Triangular}} In this roof-like{{cite book | last=Passmore | first=A.C. | title=Handbook of Technical Terms Used in Architecture and Building and Their Allied Trades and Subjects | publisher=Scott, Greenwood, and Company | year=1904 | chapter = Mitre arch | chapter-url=https://books.google.com/books?id=NawaAAAAYAAJ&pg=PA228 | access-date=2024-02-27 | page=228}} arrangement, mitre joint is usually used at the crown, thus the arch was in the past also called a mitre arch.{{cite web | title=mitre arch | website=Oxford English Dictionary | date=2023-07-01 | url=https://www.oed.com/dictionary/mitre-arch_n | access-date=2024-02-27}} Brick builders would call triangular any arch with straight inclined sides.{{cite book |last1=Brick Industry Association] |series=Technical Notes on Brick Construction |title=Brick Masonry Arches: Introduction |date=January 1995 |publisher=Brick Industry Association |page=2 |url=https://faculty-legacy.arch.tamu.edu/anichols/index_files/courses/arch631/NS6-1brickarch.pdf}} Mayan corbel arches are also sometimes called triangular due to their shape.{{sfn|Sturgis|Davis|2013|p=121|loc=Triangular Arch}}

Since the sides of a triangular arch are experiencing bending stress, it is a false arch{{cite book |title=The Oxford Dictionary of Architecture |date=2021 |publisher=Oxford University Press |isbn=9780191918742 |edition=4th | chapter = triangular arch }} in a structural sense (historically preceding the invention of true arches{{sfn|Nikolich|2020|p=1862}} and going back to Neolithic times{{Cite EB14|year=1961|volume=2|article=Arch and Vault|page=262}}). The design was used in Anglo-Saxon England until the late 11th century (St Mary Goslany) over small openings.{{sfn | Woodman | Bloom | 2003 | loc=Triangular}}{{sfn|Audsley|Audsley|1881|p=37}}

File:White Castle, arrow slit.jpg|A triangular arch built using masonry (White Castle, Monmouthshire)

File:Kabah Arch 2002.12.29 27.jpg|Mayan corbelled arch

File:Saxon doorway - geograph.org.uk - 880068.jpg|Doorway at St Peter's Church, Barton-upon-Humber (Anglo-Saxon architecture)