Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

210 Chapter Eight
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Determine the number of nails required to fasten adjacent rib
planks together. The maximum force, which tends to burst the form,
will act on the bottom rib. It will be a force of 312 lb on each foot of
diameter for a total value of 2,496 lb as calculated as follows:
2P = 312(8) = 2,496 lb
Each of the two ribs, on opposite sides of the form, must resist
one-half of this force. Thus, each rib must resist 1,248 lb, which the
joint between adjacent ribs must withstand. Using 20d nails with a
lateral resistance of 185 lb per nail, the number of nails required at the
joints can be calculated as follows:
Number of nails = (1,248 lb)/(185 lb/nail)
= 6.7
Thus, 7 nails are required at each joint.
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Placing Anchor Bolts in Concrete Foundations
When concrete foundations support machines or other equipment, it
usually is necessary to install anchor bolts at the time the concrete is
placed. A wood template, with bolt holes at the exact locations, permits
the bolts to be placed correctly, as illustrated in Figure 8-10. The template
may be made from planks or a sheet of plywood. Usually, a
short section of steel pipe or metal cylinder is installed around each
bolt to permit a slight lateral movement of the bolt and ensure that it
will fit the hole spacing in the base of the machine. The space inside
the pipe may be filled with a nonshrinkage grout.
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