elliptical dome
{{short description|Dome who bottom cross section takes the form of an ellipse}}
File:Modena San Domenico cupola ellittica.JPG, in Modena, Italy]]
An elliptical dome, or an oval dome, is a dome whose bottom cross-section takes the form of an ellipse.{{Cite web |last=Arun |first=G |date=2006 |title=Behaviour of Masonry Vaults and Domes: Geometrical Considerations |url=http://www.hms.civil.uminho.pt/sahc/2006/0299.pdf |website=Structural Analysis of Historical Constructions, New Delhi |access-date=2020-12-04 |archive-date=2020-10-23 |archive-url=https://web.archive.org/web/20201023114302/http://www.hms.civil.uminho.pt/sahc/2006/0299.pdf |url-status=dead }} Technically, an ellipsoidal dome has a circular cross-section, so is not quite the same.
While the cupola can take different geometries, when the ceiling's cross-section takes the form of an ellipse, and due to the reflecting properties of an ellipse, any two persons standing at a focus of the floor's ellipse can have one whisper, and the other hears; this is a whispering gallery.
The largest elliptical dome in the world is at the Sanctuary of Vicoforte in Vicoforte, Italy.{{Cite web |title=Visiting the largest elliptical dome in the world, in Vicoforte |url=https://www.italyrivieralps.com/2016/04/25/read-more/argomenti/video/articolo/visiting-the-largest-elliptical-dome-in-the-world-in-vicoforte.html |access-date=2020-12-04 |website=ItalyRiveirAlps|date=25 April 2016 }}{{Cite journal |last=Chiorino |first=Mario Alberto |title=Modeling Strategies for the World's Largest Elliptical Dome at Vicoforte |url=https://www.tandfonline.com/doi/abs/10.1080/15583050802063618?mobileUi=0&journalCode=uarc20 |journal=International Journal of Architectural Heritage|year=2008 |volume=2 |issue=3 |pages=274–303 |doi=10.1080/15583050802063618 |s2cid=109078429 |url-access=subscription }}{{Cite web |last=Aoki |first=Takayoshi |title=Structural characteristics of the elliptical masonrydome of the sanctuary of Vicoforte |url=https://www.researchgate.net/publication/247658003}}
In architecture
{{multiple image
| align = left
| direction = vertical
| width = 375
| footer =
| image1 = A circle, and an ellipse.png
| alt1 = A blue circle, graphed with a red ellipse
| caption1 = A blue circle, graphed with a red ellipse. An elliptical dome has an elliptical base, and an ellipsoidal dome has a circular base.
| image2 = Ellipse jjm.png
| alt2 = Wispering gallery property of ellipses
| caption2 = An ellipse, the "reflecting," "whispering gallery" property of the foci {{mvar|F}} and {{mvar|F'}} illustrated: The distance from {{mvar|F}} to {{mvar|F'}} may be great, but a whisperer at {{mvar|F}} can be heard, as {{mvar|F'}}.
Both {{mvar|-a}} and {{mvar|a}} are points of the x-axis and {{mvar|-b}} and {{mvar|b}} are points on the y-axis
}}
Elliptical domes have many applications in architecture; and are useful in covering rectangular spaces. The oblate, or horizontal elliptical dome is useful when there is a need to limit height of the space that would result from a spherical dome. As the mathematical description of an elliptical dome is more complex than that of spherical dome, design care is needed.{{Cite journal |last=Elkhateeb |first=Ahmed Ali |title=Domes in the Islamic Architecture of Cairo City: A Mathematical Approach |url=https://link.springer.com/content/pdf/10.1007/s00004-011-0103-3.pdf |journal=Nexus Network Journal|year=2012 |volume=14 |pages=151–176 |doi=10.1007/s00004-011-0103-3 |s2cid=119996869 }}
In a geodesic dome with a circular base, the triangular elements align so their edges form great circles. Although not geodesic, a new, elliptical design was patented in 1989; it uses hexagons and pentagons to form a dome with a cross section that is elliptical. Due to its mathematical derivation, this design is called "geotangent".{{Cite web |title=Polyhedral structures that approximate an ellipsoid |url=https://patents.google.com/patent/US4825602A/en}}
World examples
Elliptical domes come up in the design of all of the following:
- A number of mosques in Cairo, Egypt,
- Part of St. Peter's Basilica, in Rome, Italy{{Cite web |title=The Engineering Behind Saint Peter's Basilica |url=http://engineeringrome.org/the-engineering-behind-saint-peters-basilica/}}
- The Basilica of St. Lawrence, Asheville, in Asheville, North Carolina,
- The Church of Saint Roch, Žižkov, in Prague, Czech Republic,
- The Four Domes Pavilion, in Wroclaw, Poland,
- The Indiana Theatre, in Indiana, city of Indianapolis,
- The Joe and Rika Mansueto Library, at the University of Chicago,
- The Kanteerava Indoor Stadium, in Bangalore, India,{{Cite web |last=Kobielak |first=Sylwester |date=November 27, 2016 |title=Oval concrete domes |url=https://coek.info/queue/pdf-oval-concrete-domes-.html}}
- The Mayflower Hotel, in Washington, DC,
- The Mosque–Cathedral of Córdoba, in Andalusia,
- The Palau Nacional, in Barcelona, Spain,
- The Pisa Cathedral, in Pisa, Italy,
- The Rose Hill Mansion, Bluffton, in Bluffton, South Carolina,
- The San Filippo Neri, in Turin, region of Piedmont, Italy,
- The Sant'Andrea in Via Flaminia, in Rome, Italy,
- The Santa Caterina, Casale Monferrato, in Casale Monferrato, Province of Alessandria, region of Piedmont, Italy,
- The Seville Cathedral, Spain,
- The Skyspace Lech, Tannegg/Oberlech in Vorarlberg, the westernmost federal state of Austria,
- The State Savings Bank Building, in City of Sydney, Australia,
- The Temple Sinai, in Oakland, California,
- The Sanctuary of Vicoforte, in Italy,
- BAPS Swaminarayan Akshardham (New Jersey), in Robbinsville, New Jersey.
See also
{{portal|Architecture}}
References
{{Reflist}}
External links and references
=Creating elliptical domes=
- [https://geo-dome.co.uk/article.asp?uname=elliptcal_domes Elliptical domes site]
- [https://help.solidworks.com/2020/English/SolidWorks/sldworks/c_example_elliptical_dome.htm Creating an elliptical dome]
- [https://help.solidworks.com/2018/english/SolidWorks/sldworks/HIDD_DVE_FEAT_DOME.htm Another reference, on creating ellitpical domes]
=Calculations=
- [https://www.monolithic.org/static/calcs/advanced.html Site for calculating figures related to elliptical domes]
- [https://www.monolithic.org/calculators/advanced-dome-calculator Another site for calculations]
- [https://www.monolithic.org/calculators/dome-calculator Dome calculator]
=More general references=
- [https://asmedigitalcollection.asme.org/pressurevesseltech/article-abstract/130/1/011210/475723/Buckling-of-Externally-Pressurized-Prolate?redirectedFrom=fulltext Buckling of Externally Pressurized Prolate Ellipsoidal Domes]
- [http://www.hms.civil.uminho.pt/sahc/2006/0299.pdf An article addressing many topics, including elliptical domes] {{Webarchive|url=https://web.archive.org/web/20201023114302/http://www.hms.civil.uminho.pt/sahc/2006/0299.pdf |date=2020-10-23 }}
- [https://link.springer.com/content/pdf/10.1007/s00004-011-0103-3.pdf Use of elliptical domes, notably in Islamic architecture]