Step 13. Maximum tie spacing = 21 inches
Step 14. Because maximum tie spacing is greater than maximum stud spacing (Step 7), reduce the tie spacing to
18 inches and tie at the intersection of each stud and double wale.
Example Problem 2
Design the form for a concrete wall 40 feet long, 2 feet thick, and 10 feet high. An M919 concrete mobile mixer
is available, and the crew can produce and place a cubic yard of concrete every seven minutes. The concrete
placing temperature is estimated at 70F. The form materials you have are 2- by 4-inch lumber, 3/4-inch
plywood, and 3,000-pound (breaking strength) snap ties.
Solution Steps:
Step 1. Materials available: studs, 2 by 4 (single); wales, 2 by 4 (doubled); sheathing, 3/4-inch plywood (strong);
ties, 3,000-pound snap ties
Step 3. Plan area of form = 40 ft x 2 ft = 80 sf
Step 5. Concrete placing temperature = 70F
Step 6. Maximum concrete pressure (refer to Figure 3-3, page 3-5) = 500 lb/sf
Step 7. Maximum stud spacing (refer to Table 3-2, page 3-7) = 15 inches
Step 9. Maximum wale spacing (refer to Table 3-3, page 3-9, using 700 lb/lf load) = 22 inches
Step 11. Tie spacing based on wale size (refer to Table 3-4, page 3-11, using 1,000 lb/lf load) = 27 inches
EN5466
3-14
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