Horizontal member of support

Q.
Explain the following building terms with diagram when necessary.

• Joists
• Stringers
• Headers
• Purlins
• Rafters
• Girts
• Lintels
• Girders
• Spandrels
• Trusses

A.
In most buildings, the superstructure systems consists of floor and roof desks, horizontal members that support them, and vertical members that support the other components.

The horizontal members are generally known as beams, but they also are called by different names in specific applications. For example:

• Joists are closely spaced to carry light loads.

• Stringers support stairs.

• Headers support structural members around openings in floors, roofs, and walls.

• Purlins are placed horizontally to carry level roof decks.

• Rafters are placed on an incline to carry sloping roof decks.

See above image.

• Girts are light horizontal members that span between columns to support walls.

• Lintels are light horizontal beams that support walls at floor levels in mutistorey buildings or that carry the part of walls above openings for doors and windows.

• Girders may be heavily loaded beams of horizontal members that support other beams.

• Spandrels carry exterior walls and support edges of floors and roofs in multistorey buildings. In concrete or steel construction, an exterior beam extending from column to column usually carrying an exterior wall load is known as a spandrel beam.

• Trusses serve the same purposes as girders but consists of slender horizontal, vertical, and inclined components with large open spaces between them. The spaces are triangular in shape. Lights beams similarly formed are called open-web joists.

"a framework, typically consisting of rafters, posts, and struts, supporting a roof, bridge, or other structure."

A.
Merritt & Ricketts (2001) Building Design and Construction Handbook. Six Edition. McGraw-Hill. Page 1.11.
Pictures download from public domain within search by Google.