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

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Properties of Form Material 49
Width of
Lumber
Size Adjustment Factor
for Bending Stress, F b
Thickness
2-in. & 3-in.
4-in.
2-in. 1.5 1.5 1.15
3-in. 1.5 1.5 1.15
4-in. 1.5 1.5 1.15
5-in. 1.4 1.4 1.1
6-in. 1.3 1.3 1.1
8-in. 1.2 1.3 1.05
10-in. 1.1 1.2 1.0
12-in. 1.0 1.1 1.0
14-in. & wider 0.9 1.0 0.9
Size Adjustment for
Compression Parallel
to Grain F c
//
TABLE 4-3a
Table 4-3
Size Adjustment Factors C F
for Species of Lumber shown in
ww.EasyEngineering.n
Load-Duration C D
Typical Design Load
Permanent 0.9 Dead Load
10 years 1.0 Occupancy Live Load
2 months 1.15 Snow Load
7 days 1.25 Construction Load
10 minutes 1.6 Wind/Earthquake Load
Impact 2.0 Impact Load
TABLE 4-4 Adjustment Factors C D
for Load-Duration
Bending
Stress
Shear
Stress
Compression
Stress
Perpendicular
to Grain
Compression
Stress Parallel
to Grain
0.85 ∗ 0.97 0.67 0.8 ∗∗ 0.9
Modulus
of
Elasticity
Notes:
1. ∗ denotes when (F b
)(C F
) < 1,150 lb per sq in., C M
= 1.0.
2.
∗∗
denotes when (F b
)(C F
) < 750 lb per sq in., C M
= 1.0.
TABLE 4-5 Adjustment Factor for Moisture Content Greater Than 19%
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