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

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Properties of Form Material 45
4. Beam stability factor, C L
5. Column stability adjustment factor, C P
6. Flat use adjustment factor, C fu
7. Bearing area adjustment factor, C b
8. Buckling stiffness adjustment factor, C T
9. Repetitive member adjustment factor, C r
10. Incising adjustment factor, C i
11. Temperature factor, C t
The allowable design stress is obtained by multiplying the reference
design value by appropriate adjustment factors as follows:
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Allowable Stress for Bending,
F′ b
= (reference design value for bending) • [C F • C D • C M • C L
• C fu • C r • C i • C t
]
Allowable Stress for Shear,
F′ v
= (reference design value for shear) • [C D • C M • C i • C t
Allowable Compression Stress Perpendicular to Grain,
F′ C⊥
= (reference design value for compression ⊥ to grain)
• [C M • C b • C t • C i
]
Allowable Compression Stress Parallel to Grain,
F C
= (reference design value for compression // to grain)
• [C D • C M • C F • C P • C i • C t
]
Allowable Modulus of Elasticity for Beam Deflection Calculations,
E′ = (reference design value of modulus of elasticity, E)
• [C M • C i • C t
]
Allowable Modulus of Elasticity for Beam and Column Stability
Calculations,
E′ min
= (reference design value of modulus of elasticity, E min
)
• [C M • C T • C i • C t
]
The designer should become familiar with the specification in ref.
[4] in order to properly apply the adjustment factors for the design of
wood structures. The most common adjustment factors for construction
of temporary structures and formwork are size, load-duration, moisture,
beam and column stability, bearing, and flat use. These adjustment
factors are presented in subsequent sections of this chapter.
The adjustment factors for temperature, incising, and repetitive
member are less common in constructing temporary structures and
formwork. Temperature adjustment factors apply when the wood is
subjected to sustained elevated temperatures (100 to 150°F). For
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