ASD/LRFD Manual - American Wood Council

66 M9: WOOD STRUCTURAL PANELS
M9.3 Adjustment of Reference Design Values
General
Adjusted panel design capacities are determined by
multiplying reference capacities, as given in Tables M9.2-
1 through M9.2-4, by the adjustment factors in NDS 9.3.
Some adjustment factors should be obtained from the
manufacturer or other approved source. In the NDS Commentary,
C9.3 provides additional information on typical
adjustment factors.
Tabulated capacities provided in this Chapter are
suitable for reference end-use conditions. Reference
end-use conditions are consistent with conditions typically
associated with light-frame construction. For wood
structural panels, these typical conditions involve the use
of full-sized untreated panels in moderate temperature and
moisture exposures.
Appropriate adjustment factors are provided for applications
in which the conditions of use are inconsistent
with reference conditions. In addition to temperature and
moisture, this includes consideration of panel treatment
and size effects.
NDS Table 9.3.1 lists applicability of adjustment factors
for wood structural panels. Table M9.3-1 shows the
applicability of adjustment factors for wood structural
panels in a slightly different format for the designer.
Table M9.3-1
Applicability of Adjustment Factors for Wood Structural Panels
Allowable Stress Design
F b S′ = F b S C D C M C t C G C s
F t A′ = F t A C D C M C t C G C s
F v t v ′ = F v t v C D C M C t C G
F s (Ib/Q)′ = F s (Ib/Q) C D C M C t C G
F c A′ = F c A C D C M C t C G
EI′ = EI C M C t C G
EA′ = EA C M C t C G
G v t v ′ = G v t v C M C t C G
F c⊥ ′ = F c⊥ C M C t C G
Bending Member Example
For non-Structural I grade wood structural panels,
greater than 24" in width, loaded in bending, and used
in a normal building environment (meeting the reference
conditions of NDS 2.3 and 9.3), the adjusted design values
reduce to:
For ASD:
F b S′ = F b S C D
EI′ = EI
For LRFD:
F b S′ = F b S K F φ b λ
EI′ = EI
Load and Resistance Factor Design
F b S′ = F b S C M C t C G C s K F φ b λ
F t A′ = F t A C M C t C G C s K F φ t λ
F v t v ′ = F v t v C M C t C G K F φ v λ
F s (Ib/Q)′ = F s (Ib/Q) C M C t C G K F φ v λ
F c A′ = F c A C M C t C G K F φ c λ
EI′ = EI C M C t C G
EA′ = EA C M C t C G
G v t v ′ = G v t v C M C t C G
F c⊥ ′ = F c⊥ C M C t C G K F φ c λ
Axially Loaded Member Example
For non-Structural I grade wood structural panels,
greater than 24" in width, axially loaded, and used in a
normal building environment (meeting the reference conditions
of NDS 2.3 and 4.3) designed to resist tension or
compression loads, the adjusted tension or compression
design values reduce to:
For ASD:
F c A′ = F c A C D
F t A′ = F t A C D
EA′ = EA
For LRFD:
F c A′ = F c A K F φ c λ
F t A′ = F t A K F φ t λ
EA′ = EA
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