Use table 3-2 or table 3-3 (depending on type of
waler system) to determine the tie spacing based on
the ULW. This number is the maximum tie spacing in
inches based on wale size.
Tie wires or snap ties (depends on what system you
use) must be installed at the intersection of studs and
wales. Place the first tie at one half of the maximum
tie spacing from the end of the wale.
Estimating Studs and Wales
To determine the number of studs on one side of a
form, you need to divide the form length by the
maximum stud spacing, and add one for a starter. The
first and last stud must be placed at each end of the
To determine the number of wales for one side of
a form, you must divide the form height by the
maximum wale spacing and round up to the next whole
number. Place the first wale one half of the maximum
space up from the bottom and the remainder at the
maximum wale spacing.
To determine the time required to place concrete,
you divide the height of the form by the rate of
placement. This does NOT include the length of the
form. For example, wall height of the form is 10 feet
and the vertical rate of placement is 5 feet/hour. Your
answer is 2 hours. Figure 3-2 shows how you can
estimate man-hours per cubic yard in most situations.
These estimates are based on Seabee experiences.
*The following rules apply to figure 3-2:
1. For each 40 feet wheeled, add 25 percent.
2. For upper stories, add per story: Placed by
pump, 7 percent; placed by bucket or crane, 5 percent.
3. Construction that moves in and out of ramps,
runways, or staging is not included. For moving in and
out use 0.22 man-hours per linear foot.
4. Major items of consideration in planning
concrete placement are: method of placement,
accessibility, the rate of placement in regard to form
design and the amount and frequency of delivery is
governed by the ability to screed, tamp, and finish.
Bracing of Wall Forms
BRACES are used against wall forms (fig. 3-3) to
keep the forms in place and in alignment from mishaps
due to external forces, such as wind, personnel,
equipment, vibration, and accidents. For most military
applications, this force is assumed to be 12.5 times the
wall height, in feet. Braces (normally 2 by 4s) to be
used should be equally strong in tension as in
compression strength, or braces should be used on both
sides of a wall form.
Designing wall forms and the bracing for wall
forms should be left to the engineers. We do not have
the time or the space in this section to cover all the
formulas necessary to design forms. Refer to the
Figure 3-2.Placing concrete labor estimates from P-405.