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Girder-stand construction in the town hall of Veringenstadt

A beam is a load-bearing element in the building structure . Due to its shape and material properties, the beam is suitable for many functions. The designation according to the function of the beam, the installation location or the material is common.


Wood - steel - reinforced concrete beams

Historically, the term “beam” in carpentry first referred to the wooden beam , the association is the beam structure or entablature . Later, the term was transferred to other identical construction elements made of different materials, such as hollow box or solid wall girders made of sectional steel or reinforced concrete . The balcony is related (porch on the cantilever).

'Beam' is a component- related expression: a geometrically defined cross-section (square, round, rectangular) and a length that is relatively large determine its shape.

Functionally, horizontal beams that are only partially supported are called girders . Beams clamped in on one side are cantilever beams . Beams in the frame construction are transoms , in the roof construction purlins . Depending on the area of ​​application and trade , vertical bars are referred to as columns , standing loaded as uprights , stems , loaded or unloaded as posts, and when suspended from tensile loads as hanging columns . Inclined beams can be found under names such as rafters (roof), as struts (technical trusses), head bands, bows (diagonal struts in wooden trusses).

A beam that spans a building opening as part of a wall is a lintel . The row of beams in one plane, for the purpose of covering the entire area, is the horizontal beam position , vertically with the horizontal beam the blockwork , with the standing beam the stud structure .

In structural engineering , a "beam" is a component that, unlike a bar, is loaded perpendicular to its longitudinal axis. The beam can absorb forces in the longitudinal and transverse direction, whereby size, material and shape determine the use. The field of structural engineering that deals with the beam is beam theory .

Wooden beams

Wooden beams decorated with carvings. Loulan , China

The wooden beam, also known in the region as a tram , is usually made by sawing a tree trunk ( timber ) lengthways. The grain direction thus runs in the sawing direction. In the past, beams were often made by cutting with a broad ax . The beam is the strongest class of sawn timber and is also simply called a “tree” (as it has been used as an expression for ships, cranes or roof structures).

Traditionally, the height of ceiling beams and rafters was chosen about 1.4 times greater than the width. Today there is a tendency towards double the height or even cross-sections that correspond to a plank placed on edge (e.g. 20 × 5 cm). However, the latter requires special measures to prevent the beam from twisting.

Beams are made by deliberately cutting up a tree trunk: a distinction is made between sharp-edged and mis-edged beams. Missing-edged beams still have remains of the contour of the tree trunk. After the possible longitudinal division of the tree trunk and use of the maximum trunk cross-section, a square or rectangular whole wood (one bar), half wood (two bars), cross wood (four bars) or sixth wood (six bars) is created.

The end of the beam is also called the head of the beam and in special cases can have visible decorations.

All connection options and types of processing for wood are common on the beam and are determined by the type of application.

Web links

Commons : Bars  - collection of images, videos and audio files
Wiktionary: bars  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. GEBÄLK, n. Beams in timber construction of all kinds. In: Jacob Grimm , Wilhelm Grimm (Hrsg.): German dictionary . tape 4 : Forschel – retainer - (IV, 1st section, part 1). S. Hirzel, Leipzig 1878 ( ).
  2. TRAM, m., The bar; nom. sing. tram also. In: Jacob Grimm , Wilhelm Grimm (Hrsg.): German dictionary . tape 21 : T – Treftig - (XI, 1st section, part 1). S. Hirzel, Leipzig 1935 ( ).