Lumber-CSA-20260201

Lumber - Bending Capacities - CSA O86

Lumber size and orientation
Lumber
Width			b	=		in		mm
Depth			d	=		in		mm
Cross section			A	=		in²		mm²
Section modulus			S	=		in³		mm³
Moment of inertia			I	=		in⁴		mm⁴
Wood properties
Wood species and grade
Bearing resistance			Fcp	=		psi		MPa
Planar shear resistance			Fv	=		psi		MPa
Bending resistance			Fb	=		psi		MPa
Modulus of elasticity			E	=		psi		MPa
Deflection criteria
Allowable relative deflection
Allowable absolute deflection			Δmax	=		in		mm
Size of supports
Support width			Lcp	=		in		mm
Support area			Acp	=		in²		mm²
Factors
Load factor					α	=
Resistance factor					φ	=
Resistance factor (bearing)					φb	=
Load-duration					KD	=
System					KH	=
Service-condition			Shear		KSv	=
			Bending		KSb	=
			Bearing		KScp	=
			Deflection		KSE	=
Treatment			Un-treated		KT	=
Size factor					KZv, KZb	=
Size factor (bearing)					KZcp	=
Lateral stability					KL	=
Bearing length					KB	=

Allowable capacities
Allowable bearing	(KD, KScp, KT, KB, KZcp,α,φb)		B	=		lbf		kN
Allowable shear	(KD, KH, KSv, KT, KZv,α,φ)		V	=		lbf		kN
Allowable moment	(KD, KH, KSB, KT, KZB, KL,α,φ)		M	=		lbf•ft		kN•m
Modulus of elasticity	(KSE, KT)		Ef	=		psi		Mpa
Bending stiffness	(Ef x I)		EI	=		lbf•ft²		kN•m²
Allowable loads (imperial)
		UDL ( PLF )					Point load ( lbf )
Span ( ft )	Criteria	Single span	Double span		Triple span		Single span
	R
	V
	M

	Δmax
Allowable loads (metric)
		UDL ( kN/m )					Point load ( kN )
Span ( m )	Criteria	Single span	Double span		Triple span		Single span
	R
	V
	M

	Δmax