|
A king post (or king-post or kingpost) is a central vertical post used in architectural or bridge designs, working in tension to support a beam below from a truss apex above (whereas a crown post visually similar, supports items above from the beam below). In aircraft design a strut called a king post acts in compression, similarly to an architectural crown post. Usage in mechanical plant and marine engineering differs again, as noted below. ==Architecture== A king post extends vertically from a crossbeam to the apex of a triangular truss. The king post connects the apex of the truss with its base, holding up the tie beam (in tension) at the base of the truss. King posts were used in timber framed roof construction in Roman buildings,〔Perring, Dominic. The Roman house in Britain. London: Routledge, 2002. 119. ISBN 0415221986 "The king-post roof was possibly a Hellenistic innovation, but is first positively attested by a bronze copy in the second-century AD porch of the Pantheon at Rome."〕 medieval architecture in buildings such as parish churches and tithe barns. They also appear in Gothic Revival architecture, Queen Anne architecture and into modern times. Said to be the oldest and simplest truss, the oldest surviving roof truss in the world〔Feilden, Bernard M.. Conservation of historic buildings. 3rd ed. Oxford: Architectural Press, 2003. 51. ISBN 0750658630〕 built between 548 and 565〔Din, Mursi Saad El et al.. Sinai: the site & the history : essays. New York: New York University Press, 1998. 80. ISBN 0814722032〕 is a king post truss in Saint Catherine's Monastery, Egypt. Also, king post trusses are used to construct wood and metal bridges. The post can be replaced with an iron rod called a king rod (or king bolt) and thus a king rod truss.〔Siegele, H. H.. ''Roof Framing''. New York: Sterling Pub. Co., 1980. 99. ISBN 0806986263〕 The king post truss is also called a "Latin truss".〔Patrick Hoffsummer, ed. Roof frames from the 11th to the 19th century: typology and development in Northern France and in Belgium : analysis of CRMH documentation. Turnhout, Belgium: Brepols, 2009. Print. ISBN 2503529879〕 In traditional timber framing, a crown post looks similar to a king post, but it is very different structurally. The king post is in tension, usually supporting the tie beam as a truss but the crown post is supported by the tie beam and is in compression. The crown post rises to a crown plate immediately below and supporting collar beams, it does not rise to the apex like a king post. Historically a crown post was called a king post in England but this usage is obsolete.〔Harris, Richard. Discovering Timber-Framed Buildings. 3rd ed. Princes Risborough: Shire, 1993. pp.79, 85, 87, 95 .〕 An alternative truss construction uses two queen posts (or queen-posts). These vertical posts, positioned along the base of the truss, are supported by the sloping sides of the truss, rather than reaching its apex. A development adds a collar beam above the queen posts, which are then termed queen struts. A section of the tie beam between the queen posts may be removed to create a hammerbeam roof. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「king post」の詳細全文を読む スポンサード リンク
|