LVL Handbook EUROPE

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4. STRUCTURAL DESIGN OF LVL STRUCTURES
4.3.7 Bending stress at an angle to the grain
The bending stresses at an angle α to the grain should satisfy
the following expression 32:
σ_(m,α,d)≤f_(m,0,d)/(f_(m,0,d)/f_(m (4.15)
where
σm,α,d is the bending stress at an angle α to the grain
When the characteristic bending strength fm,90,k is not de-
clared for the product, it should be assumed that fm,90,k = ft,90,k.
In Figure 4.14, the edgewise bending strength values of LVL 48
P and LVL 36 C at different angles are shown as graphics with
this assumption.
4.3.8 Tension stress at an angle to the grain
The tensile stresses at an angle α to the grain should satisfy the
following expression 32:
σ_(t,α,d)≤f_(t,0,d)/(f_(t,0,d)/f_(t,90,d) 〖 ∙ (4.16)
where
σt,α,d is the tensile stress at an angle α to the grain
In Figure 4.16, graphically illustrates tensile strength val-
ues of LVL 48 P and LVL 36 C at different angles.
More advanced instructions on determining the effect of
an angle to the grain on LVL strength properties may be found
in the manufacturers’ technical documentation.
Figure 4.15. Angle α between span direction and grain direction of
surface veneer.
m,α,d ≤ m,0,d
m,0,d m,90,d∙ sin2 + m,0,d v,d ∙ sin ∙ cos + cos2 (4.15)
t,α,d ≤ t,0,
t,0,d t,90,d∙ sin2 + t,0,d v,d∙ sin ∙ cos + cos2 (4.16)
Figure 4.17. Characteristic edgewise tension strength at an angle α
to grain.
0
5
10
15
20
25
30
35
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
[N/mm
2]
Angle α between stress and grain [°]
Characteristic edgewise tension strength ft,edge,α,k
at an angle α to grain
LVL 48 P
LVL 36 C
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
[N/mm
2]
Angle α between stress and grain [°]
Characteristic edgewise bending strength f m,edge,α,k
at an angle α to grain
LVL 48 P
LVL 36 C
Figure 4.16. Characteristic edgewise bending strength at an angle
α to grain.
126 LVL Handbook Europe