Question:
Is it possible to design built-up timber cross-sections?
Answer:
In timber design, beams are often built from several timber elements. The individual elements can be connected with glue, nails, bolts, or dowels. A glued connection is to be assumed as rigid. In the case of dowel‑type fasteners, the joint is compliant (slip joint), and the cross‑section properties of the connected elements cannot be fully applied.
In RFEM and RSTAB, it is possible to consider the compliance (slip) of the connection in the individual layers. This can be done by specifying the coefficient of compliance gamma, which can be determined by means of the gamma method, for example according to EN 1995‑1‑1 (Annex B). By using this coefficient, the Steiner components of the cross-section parts are reduced, resulting in an effective bending stiffness.
In addition, it is possible to assign different materials to the individual cross‑section. To do this, use the "Hybrid" function, in which one of these materials is used as reference for the determination of the ideal cross-section properties.
