A-frame
An A-frame is a simple structure which resembles the capital letter A, where two lengths lie at an angle meeting at the top and a central brace ties them together. Where self standing the frame may have three angle lengths meeting at the top, so the sides form a triangular pyramid or tetrahedron with equilateral triangles on each side, or four length forming a pyramid, with a tie between each.
The structure can be seen at many different scales, including early tipi or tent shaped shelters covered in hides, structures over wells, or simple sawhorses with two A-frames with rigid connections to a horizontal beam. Most modern day timber roof structures have a tie beam and two rafters that form an A-frame which is tied to other A-frames via a ridge beam and purlins forming the roof structure.
At a larger scale, the Eifell tower although with curved angle lengths to resist wind loads, represents in its simplest for an A-frame, whilst the more contemporary London eye is supported by a single frame base, with a series of wires acting as the ties.
A similar structure might be referred to in English as a trestle, which in its simplest form is a similar framework consisting of a horizontal beam supported by two pairs of sloping legs, used to support a flat surface such as a table top. In the case of trestle tables the two pairs of sloping legs may make up a flat frame joined together at the top, often with a hinge and with a tie at the bottom stoping the supports from spreading and collapsing, in combination this makes up an A frame.
[edit] Related articles on Designing Buildings
Featured articles and news
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.
Quick summary by size, shape, test, material, use or bonding..