Their is always some variation in the design values calculated in timber. Therefore we need to apply the required adjustment to them.

**Case- Extreme Fiber Bending**

F_{b}‘=F_{b}C_{D}C_{M}C_{t}C_{L}C_{F}C_{V}C_{fu}C_{r}C_{c}C_{f}

where

F_{b}‘ – Adjusted design value

F_{b}= design value for extreme fiber bending

C_{D}= load duration factor

C_{M} =wet service factor

CC_{t} =temperature factor

C_{L} =beam stability factor

C_{F} =size factor applicable only to visually graded, sawn lumber and round timber flexural members

C_{v} =volume factor applicable only when beams are glued or laminated

C_{fu}= flat use factor applicable only to dimension- lumber beams 2 to 4 in (50.8 to 101.6 mm) thick and glued-laminated beams

C_{r}= repetitive-member factor—applicable only to dimension-lumber beams 2 to 4 in (50.8 to101.6 mm) thick

C_{c} =curvature factor—applicable only to curved portions of glued-laminated beams

C_{f} =form factor

When the beams are glued, laminated we have to use the smallest of the two C_{L} or C_{c}

**Design value for Tension **

F_{t}‘= F_{t}C_{D}C_{M}C_{t}C_{F}

where

F_{t}‘ – Adjusted design value

F_{t} – Design value for tension.

**Adjustment For shear**

F_{v}‘=F_{v}C_{D}C_{M}C_{t}C_{H}

where

F_{v}‘ – Adjusted design value

F_{v}– design value for shear and C_{H} is the shear stress factor >=1 permitted for F_{v}parallel to the grain for sawn lumber members.

** Adjustment for compression perpendicular to the grain**

*design value F*_{c1}‘is obtained from

F_{c1}‘=F_{c1}C_{D}C_{t}C_{b}

where

F_{c1}is the design value for compression perpendicular to the grain

C_{b} is the bearing area factor.

**Adjusted design value for compression parallel to the grain**

F_{c}‘=F_{c}C_{D}C_{M}C_{t}C_{F}C_{p}

where

F_{c} is the design value for compression parallel to grain

C_{p} is the column stability factor.

**Adjusted design value for end grain in bearing parallel to the grain**

F_{g}‘= F_{g}C_{D}C_{t}

where

F_{g} is the design value for end grain in bearing parallel to the grain.

**The adjusted design value for modulus of elasticity, E’ **

E’= EC_{M}C_{T}C

where E= design value for modulus of elasticity

C_{T}= buckling stiffness factor

C=other appropriate adjustment factors