Headband
A headband (also bow or headband ) is a strut that the carpenter uses between a horizontally ( beam , purlin , frame , etc.) and a vertical piece of wood ( support , stand , post, stem, etc.) to provide additional stiffening of construction.
A headband is often used to make building roof structures easier. The headband prevents the roof structure from folding over in the direction of the gable. After installing the rafters , however, a wind panicle is usually attached, which ensures better stiffening of the roof structure.
In addition to absorbing horizontal forces, the headband also carries vertical loads and guides them into the stand. In the roof structure, the headband reduces the span and thus the deflection of the purlin, which is stressed by the rafters.
If a triangular wood is used instead of the strut, this is called the head angle wood .
features
Carpentry wood joints are usually thought of as joints . A rigid corner can be formed with a headband .
A headband is made up of individual rods, the individual nodes of which are articulated to a good approximation. However, if you look at the entire system from a certain distance, this system of three rods as a whole can also be viewed as a rigid knot (instead of looking at a headband in detail).
The central or ridge purlin rests on stems in the longitudinal structure of a roof structure . The purlin supports the rafters. In addition, the purlins also support the gable at their end . If the gable is not stiffened by transverse walls, it is common to attach it to the purlins with wall anchors .
In the case of very flat roofs, the wind panes alone do not have a sufficient stiffening effect, so that the stiffening of the roof in the longitudinal direction ("the longitudinal bracing") is largely ensured by the head straps .
Headbands are usually used at an angle of 45 ° between the stems and the purlin. The connection is traditionally carried out by means of a strut pin ( pin connection ). The pin is in the middle of the cross-section and is therefore no longer visible after the connection has been assembled. The figure above shows a rather complex wood connection by means of lateral lapping or combing .
Today the connections are often made quickly and easily with nail plates or wooden tabs.
Headbands should always be arranged from both sides of intermediate stems. In the case of one-sided headbands or headbands that are subsequently removed on one side, bending moments arise in the stems for which they are usually not dimensioned and which should be avoided.
A headband restricts the headroom in the attic and thus may hinder the use and expansion of the attic.
Possible uses
See also
literature
- Balder Batran, Herbert Bläsi and others: Basic knowledge of construction. 14th edition. Handwerk und Technik Verlag, 2002, ISBN 3-582-03500-X , p. 176.
- Martin Mittag: Building Design. Vieweg Verlag, 2000, ISBN 3-528-02555-7 , p. 375.
Web links
Individual evidence
- ↑ Manfred Gerner : Handwerkerlexikon. Dictionary for the building trade. 2nd edition, Deutsche Verlags-Anstalt, Stuttgart 1993, p. 65
- ↑ Hejkrlik, Gerhard and Weber, Michail: Upgrading a Wilhelminian style house for earthquake loads . In: Wiley Online Library (Ed.): Stahlbau . Vol. 80, No. 5 , 2011, p. 364-371 ( wiley.com ).
- ↑ One-sided headband dangerous in the Google book search - was already known in 1851