2.1 The pattern of grain surface movement relates
to a transverse section across the portion of the compartment being
considered and the resultant heeling moment should be multiplied by
the length to obtain the total moment for that portion.
2.2 The assumed transverse heeling moment due
to grain shifting is a consequence of final changes of shape and position
of voids after grain has moved from the high side to the low side.
2.3 The resulting grain surface after shifting
shall be assumed to be at 15° to the horizontal.
2.4 In calculating the maximum void area that
can be formed against a longitudinal structural member, the effects
of any horizontal surfaces, e.g. flanges or face bars, shall be ignored.
2.5 The total areas of the initial and final voids
shall be equal.
2.6 Longitudinal structural members which are
grain-tight may be considered effective over their full depth except
where they are provided as a device to reduce the adverse effect of
grain shift, in which case the provisions of A 10.9 shall apply.
2.7 A discontinuous longitudinal division may
be considered effective over its full length.