Coupling beam
There are various definitions for coupling girders that relate to girders used in timber engineering .
On the one hand, short girders are referred to as coupling girders, which are articulated at both ends to the cantilevered ends of cantilever girders, that is, they couple with one another .
Gerber girders (articulated girders), which are each supported at a single point near one of their ends and thus protrude at both ends, are also called coupling girders. In every field, except one, there is exactly one joint. If the remaining field also had a joint or if the beam breaks in this field, the entire system becomes unstable. This type of beam simplifies the assembly of the trusses.
Finally, the term is also used for continuous beams that are rigidly connected to one another without joints. The aim of constructions with continuous beams is to obtain the most uniform possible bending moment .
The rigid connection can be made by overlapping joints, which then usually lie over the support points on the girders (as indicated in the picture). The double cross-section over the support points reduces the material tension at the point of the highest bending moment and thus optimizes the cross-sectional utilization of the beam.
This type of coupling beam is often used as purlin rafters on roofs with trapezoidal sheet metal roofing . One then speaks of coupled purlins .
References and footnotes
- ↑ Mechanics : Part I. Auxiliary sciences. 2nd volume, Fritz Rabbow
- ↑ Practical Structural Analysis , Part 1, Walter Wagner, Gerhard Erlhof
- ↑ Timber construction: Dimensioning and construction , Willi Mönck, Dipl.-Ing., Wolfgang Rug, Prof. Dr.-Ing.
- ↑ Wood Lexicon. 4th edition, Leinfelden-Echterdingen 2003, DRW-Verlag, Lemma Koppelträger .