Bracket

The term 'bracket' typically refers to a right-angled fixing device made from metal, wood or stone, but it may also be used to refer to various items of ironmongery or fixing devices such as flat metal plates for connecting two separate items or a device for hanging.

[edit] History

Traditionally stone brackets were used to create an overhang from a wall that could carry the load of a beam, plinth or cornice. They would often be seen in pairs with one at each end of the item being supported. These were relatively short, protruding about half the length of their height, or less, and so as such were not cantilevered (this was also known at the time as a modillion). The word itself may have originated from the French braquette and the Spanish bragueta, possibly connected to the Germanic braca or broc, which refers to breeches or supports, also paired.

Console brackets might have been found around door openings in Greece, these were only slightly protruding supports for cornices or headers, also known as an ancon, or ancones. Consoles were decorative as well as structural, often with a sculptural scroll-shaped S curve on the underside, also known as a double-ogee, the shape usually ended in spirals (or volutes). The earliest known examples of scroll console brackets are found within the Temple of Concord in Rome dating from between 7 BCE and 10 CE.

A corbel bracket was another type of supporting mechanism, though less decorative. It was normally formed as part of a structure where stone or brickwork step out to form a perpendicular support. The word is thought to stem from the French for crow because the structure resembles a bird's beak. It was commonly used in both medieval and renaissance times as well as in Babylonian architecture where two would create a corbel arch and multiple corbels would form a corbel vault that would support a roof.

[edit] Modern

The word corbel is still used today to describe a brickwork shelf or ledge, formed by courses of masonry that progressively project from the face of a wall. Racking is the opposite of corbelling and describes masonry in which progressive courses of brickwork step back from the face of the wall. Corbelling might be used around the eaves of a building where the wall meets a roof, whilst racking might be used at the top of a pier prior to coping or capping.

The term bracket is used today to describe a wide variety of fixings, fasteners or connector devices (often called ironmongery or hardware), these normally couple or join two items and are to some extent structural. A right angle support performing the same function as the historical term bracket is likely to be called an angle bracket also with a variety of uses.

Some examples of hardware that might be called a bracket are given below:

• Joist hangers - used to hang joists from structural members.
• Joist straps - used to fix ceiling joists at the sides to hanging beams, rafters to beams or floor joists to bearers.
• Timber connectors - a general term for brackets connecting a variety timbers in different ways.
• End frame clamps - adjustable clamps to connect modular steel or aluminium frame systems.
• Beam hangers - function similarly to joist hangers but are normally larger and with through bolts.
• Truss base fan or gable plates - with double or triple flat brackets either side connected with through bolts.
• Post bases or post anchors - square or round brackets with a plate to fix pots at the horizontal plain.
• Rafter clips or angle brackets - simple 90 degree angles for static connections.
• Rafter seams - mid point connectors for beams.
• Post-to-beam brackets - designed to create rigid connections between posts and roof beams.
• Bicycle bracket - hanger, open bracket storage device, fixed to a wall to hold a bicycle.
• Shelf bracket - 90 degree angle that supports a shelf on the horizontal.

This list is not exhaustive and many other types of connectors, metal, wooden or plastic might be referred to as a bracket in modern construction.

[edit] Related articles on Designing Buildings

• Architrave.
• Console bracket.
• Corbel.
• Cornice.
• Fascia.
• Shop.