The single-step joint – a traditional carpentry joint with new possibilities

Figures & data

1 Step joints in the upper panels, CNC milling examples in the lower panels.

2 Geometry and forces in a single-step joint. Support is not shown. The shear stresses of e are an indication of the shear distribution along BD and are based on Krabbe (1962).

3 Failure criteria for GL24h.

Table 1 Geometric limitations to avoid shear failure.

	Eurocode	Swiss	German	Austrian
lmin	…	150 mm	200 mm	200 mm
lmax	…	…	8 tv	8 tv

4 Combined shear and stresses perpendicular to the grain based on the work of Steiger and Gehri (2011).

Table 2 Design rules to limit the reduced area.

Joint	Eurocode	Swiss, German and Austrian
Single-step joints	…	Φ	≤50	50 ≥ φ ≤ 60	≥60
		tv	≤h/4	Interpolation	≤h/6
Two-sided single-step joints	…	tv = h/6 for all φ

Krabbe E. 1962. On the stress in a single step joint. Holz als Roh- und Werkstoff. Heft. 5:7.

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Steiger R and Gehri E. 2011. Interaction of shear stresses and stresses perpendicular to grain. Alghero, Italy.

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