Tension Connections in RF-/JOINTS Timber - Steel to Timber
Tips & Tricks
In the case of tension connections with cleats subjected to unilateral loading, the external members (side timber) are loaded by an additional bending moment due to the eccentric load distribution. However, this fact is not mentioned in EN 1995‑1‑1 and is considered in the National Annex to DIN EN 1995‑1‑1 by the reduction of the tensile strength. This reduction depends on the pull‑off strength of the fasteners.
For screws, bolts, guide pins, and nails without pre‑drilled holes, you can consider the simplified additional moment in the design, which only applies 2/3 of the tensile strength of the cleats. For dowels and nails with pre‑drilled holes, you can also perform this design when additionally arranging the side timber with pull‑off strength in order to prevent bending. If the buckling is not prevented for the dowels and nails with pre‑drilled holes, you can apply only 40 percent of the tensile strength.
Since this design could be regarded as the negligence of EN 1995‑1‑1, the procedure described above is active by default for all National Annexes. Optionally, you can deactivate the design so the tensile strength is set to 1.0. When using dowels or nails without pre‑drilled holes, you can select the prevention of bending in Window 1.5 Geometry. For all other fasteners, the reduction is done automatically.
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Design of indirect timber connections with dowel-type fasteners and steel plates according to NDS and Eurocode 5