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

76 Chapter Four
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Size of Nail,
penny-weight
Diameter,
in.
Species of Wood and Specific Gravity
Southern
Pine
S.G. = 0.55
Douglas
Fir-Larch
S.G. = 0.50
4d 0.099 31 24 17
6d 0.113 35 28 19
8d 0.131 41 32 22
10d 0.148 46 36 25
12d 0.148 46 36 25
16d 0.162 50 40 27
20d 0.192 59 47 32
30d 0.207 64 50 35
40d 0.225 70 55 38
50d 0.244 76 60 41
Hem-Fir
S.G. = 0.43
Note:
1. See National Design Specification for Wood Construction for additional adjustments
that may be appropriate for a particular job condition.
Withdrawal Design Values for Common Wire Nails Driven into
Side Grain of Main Member, lb per in. of Penetration
TABLE 4-23
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The NDS presents four equations for calculating the lateral design
values of nails in wood-to-wood connections. The allowable design
value is the lowest result of the four equations. These equations
include the variables described in the preceding sections. Table 4-24
provides the nominal lateral design values for common wire nails
and several species of wood that are commonly used for formwork in
dry conditions, less than 19% moisture content. Design values for other
species of wood and other types of fasteners can be found in ref. [1].
The values given in Table 4-24 are based on nails driven in the
side grain with the nail axis perpendicular to the wood fibers. Design
values are based on nails driven in two members of identical species
of seasoned wood with no visual evidence of splitting. The nominal
lateral design values of nails are based on nails that are driven in the
side grain of the main member, with the nail axis perpendicular to the
wood fibers. When nails are driven in the end grain, with the nail axis
parallel to the wood fibers, nominal lateral design values should be
multiplied by 0.67. The values are based on a nail penetration into the
main member of 12 times the nail diameter. The minimum nail penetration
into the main member should be six times the nail diameter.
There should be sufficient edge and end distances, as well as spacings
of nails to prevent splitting of the wood.
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