Figure 3-3.Diagonal bracing supports.
American Concrete Institute (ACI) or the
Architectural Graphic Standards (AGS) for more
information on designing of forms.
COLUMN FORM DESIGN
As with wall forms, column forms are designed
according to step-by-step procedures. Wooden forms
for a concrete column should be designed by the
1. Determine the materials available for sheathing,
yokes, and battens. Standard materials for columns
forms are 2 by 4s and 3/4-inch plywood.
2. Determine the height of the column.
3. Determine the largest cross-sectional dimension
of the column.
4. Determine the yoke spacing, as shown in table
3-4, by reading down the first column until the correct
height of the column is reached. Then read horizontally
across the page to the column headed by the largest
cross-sectional dimension. The center-to-center spacing
of the second yoke above the base yoke will be equal to
the value in the lower interval that is partly contained in
the column height line. All subsequent yoke spacings
may be obtained by reading up the height column to the
top. This procedure gives maximum yoke spacings.
Table 3-4 is based upon use of 2 by 4s and 3/4-inch
sheathing. For example, if you had to construct a
9-foot column, the spacing of the yokes starting from
the bottom yoke would be 8", 8", 10", 11", 12", 15",
17", 17", and 10". The space between the top two yokes
has been reduced because of the limits of the column
Because of their height and relatively small
cross-sectional area, column forms require four-way
bracing to ensure alignment and resistance to wind and
various other lateral forces that may occur during the
placement of the concrete.
OVERHEAD SLAB FORM
The general goal of slab form design is a balanced
form design. Careful consideration must be given to
the design of the formwork due to the danger of failure
caused by the weight of the concrete and the live load
(LL) of the equipment and personnel on the forms. The
following procedures uses some of the same figures
used in the wall form design.
See figure 3-4 for the nomenclature for a typical