Conoid shell
A conoid is a special kind of warped ruled surface which, as a curved shell roof, can be used as an alternative to a barrel vault. The basic principle is that one edge of the shell is curved while the opposite edge is kept straight. In architecture, this is referred to as a ‘right conoid’.
Two basic geometrical forms are encountered:
- A straight line is moved along a curved line at one end and a straight line at the other end, the resultant shape being cut to the required length.
- A straight line is moved along a curved line at one end and a different curved line at the other end.
The end consists of a reinforced concrete or steel lattice, which serves as a stiffening beam to prevent shell deformation. Support is required at all corners.
Spans of up to 12 m with chord lengths of up to 24 m are possible. The typical chord-to-span ratio is 2:1.
When conoids are made of reinforced concrete they require formwork on which to set the reinforcing steel and pour the concrete. The initial cost of making the formwork is usually high, but it can be reduced by pouring many shells on the same form.
There can be a solid infill or glazed end diaphragm. Glass panes set between adjacent conoids at the curved front of each conoid can allow for illumination. If the conoids face north they get the best natural light, which can be important for space such as factories.
Conoid shells are an ideal shape for cantilevered roofs covering the stands of stadiums with either a curvature up or a curvature down.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Anticlastic.
- Barrel vault.
- Cantilever.
- Folded plate construction.
- Hyperbolic paraboloid.
- Long span roof.
- Megastructure.
- Pendentive dome.
- Portal frame.
- Shell roof.
- Suspended ceiling.
- Synclastic.
- Tensile structures.
- Types of ceiling.
- Types of dome.
- The history of fabric structures.
[edit] External references
- ‘Building Construction Handbook’ (6th ed.), CHUDLEY, R., GREENO, R., Butterworth-Heinemann (2007)
- ‘The story of a right wavelet conoid’ , J. Dolezal (2011)
Synclastic.
Featured articles and news
BSRIA Market Intelligence Reports
World Building Automation and Control Systems (BACS) 2022
Statement of health and early intervention.
The importance of regular check-ups
And related links on DB.
Sustainable urban drainage systems SUDS
Rooflights, skylights, roof windows and Part L
Shedding some light on the new Building Regulations.
Interview with historic built environment surveyor.
Upgraded membership category now requires assessment.
The average kinetic energy of molecules
Temperature in buildings, explained on DB
Women and unequal pay in project management
Main barrier to entering the profession, new study reveals.
IHBC’s response to Parliamentary Committee
On Levelling-Up and Regeneration Bill.
Finalists for 2022 CIOB Awards revealed
Over 70 managers and organisations shortlisted for the 14 awards.
Types of building sensors on BD
From biometric to electrical current, chemical and more.
Government mandates detectors in rented homes
Changes are due to come into force on 1st October 2022.
80% of major government projects are rated red or amber
Heed advice and insight of this report IPA tells the government.
The end of the games but continued calls for action
From the Commonwealth Association of Architects.
Sustainable urban drainage systems SUDS