impregnated with waterproofing compound.
Figure 7-6 shows an assembled column and footing
form. After constructing the footing forms, build the
column form sides, and then nail the yokes to them.
Figure 7-7 shows a column form with two styles
of yokes. View A shows a commercial type, and view
B shows yokes made of all-thread bolts and 2-by
material. Since the rate of placing concrete in a
column form is very high and the bursting pressure
exerted on the form by the concrete increases directly
with the rate of placing, a column form must be
securely braced, as shown by the yokes in the figure.
Because the bursting pressure is greater at the bottom
of the form than it is at the top, yokes are placed closer
together at the bottom.
The column form should have a clean-out hole cut
in the bottom from which to remove construction
debris. Be sure to nail the pieces that you cut to make
the clean-out hole to the form. This way, you can
replace them exactly before placing concrete in the
column. The intention of the clean-out is to ensure
that the surface which bonds with the new concrete is
clear of all debris.
Figure 7-6.-Form for a concrete column.
Figure 7-7.-Column form with scissor clamp (View A), and
yolk and wedge (View B).
Wall forms (figure 7-8) may be built in place or
prefabricated, depending on shape and desirability of
Figure 7-8.-Form for a concrete wall.