Aluminium Design and Construction John Dwight

(11.20a)
(11.20b)
where p w , p f =limiting stresses (Sections 11.3.4, 11.3.5), g=weld throat
dimension, and t=lesser thickness of the connected plates.
11.3.7 Welds under combined loading
(a) Transmitted force inclined to axis of weld
When, at any point in a weld, the transmitted force P – is inclined � at
to the axis, the weld can be checked using an interaction diagram such
as that shown in Figure 11.11,
where: P – t , P– l =components of P– acting transverse and parallel to the
axis of the weld, under factored loading,
P – ct , P– cl =calculated resistances per unit length to transverse and
longitudinal force, each on its own,
� m =material factor.
The proposed interaction rule, using straight lines, is offered in preference
to the British Standard rule (quadrant) because it avoids the need to
worry about interaction when � is close to 0° or 90°.
(b) Moment combined with transverse force
For a full penetration butt, having to transmit axial moment M at the
same time as transverse force P t , the requirement is that:
(11.21)
where: x 1-� = mM – /M – c
P – t , M– =transmitted force and moment per unit length, when factored
loading acts on the structure,
P – ct , M– c =calculated resistances per unit length, each on its own,
� m =material factor.
(c) Moment combined with transverse and longitudinal force components
When a full penetration butt is required to transmit a longitudinal
force, in addition to axial moment and transverse force, the interaction
rule in Figure 11.11 may be used with P – ct replaced by xP ct .
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