Civil Engineering Reference
In-Depth Information
Glulam strength class
GL 24h
GL 28h
GL 32h
GL 36h
Glulam strength class
GL 24c
GL 28c
GL 32c
GL 36c
Bending strength
f
m,g,k
24
28
32
36
Bending strength
f
m,g,k
24
28
32
36
Tension strength
f
t,0,g,k
16.5
19.5
22.5
26
Tension strength
f
t,0,g,k
14
16.5
19.5
22.5
f
t,90,g,k
0.4
0.45
0.5
0.6
f
t,90,g,k
0.35
0.4
0.45
0.5
Compression
strength
f
c,0,g,k
24
26.5
29
31
Compression
strength
f
c,0,g,k
21
24
26.5
29
f
c,90,g,k
2.7
3.0
3.3
3.6
f
c,90,g,k
2.4
2.7
3.0
3.3
Shear strength
f
v,g,k
2.7
3.2
3.8
4.8
Shear strength
f
v,g,k
2.2
2.7
3.2
3.8
Modulus of
elasticity
E
0,g,mean
11 600
12 600
13 700
14 700
Modulus of
elasticity
E
0,g,mean
11 600
12 600
13 700
14 700
E
0,g,05
9400
10 200
11 100
11 900
E
0,g,05
9400
10 200
11 100
11 900
E
90,g,mean
390
420
460
490
E
90,g,mean
320
390
420
460
Shear modulus
G
g,mean
720
780
850
910
Shear modulus
G
g,mean
660
720
780
850
Density
p
g,k
350
380
410
430
Density
p
g,k
380
410
430
450
Table 19.7 Characteristic values for combined glulam (BSI, 1999).
Permission to reproduce extracts from BS EN 1194 is granted by BSI
Table 19.6 Characteristic values for homogeneous glulam (BSI, 1999).
Permission to reproduce extracts from BS EN 1194 is granted by BSI
Note that many of the board materials do not have values for
Service Class 3 indicating that they should not be used in this
environment.
Where a single grade of material is used the k
mod
value is
given in
Table 19.9
. Where two different materials are used,
for example, a nail through OSB/3 into C16 softwood then
01
=
600
0
01
for rectangular glulam in the range 1.0 ≥ k
h
≤ 1.1 i.e.
h
for depths 600 mm to 235 mm
k
h
for LVL in bending
S
k
mod d od mod
=
d
kk
d
kk
d o
kk
od1
=
300
h
=
d m
mo
k
mo
The possibility of unfavourable deviations of the material or
product property from its characteristic value is covered by the
partial material factor γ
M
as given in
Table 19.10
taken from
the UK NA Table NA.3.
Modifi cation factors for the dimensions of members are:
k
1
k
mo
k
mo
mod
d
2
mo
for rectangular LVL in the range 1.0 ≥ k
h
≤ 1.2 i.e. for
depths 300 mm to 65 mm
Note that the index
s
may be taken as 0.12 but should be
checked against manufacturer's information.
k
l
is the length factor for LVL in tension
k
h
the depth factor in bending or width factor in tension members
s
/
2
=
02
3000
=
150
0
02
for rectangular LVL in the range 1.0 ≥ k
l
≤ 1.1, i.e.
for lengths 3000 mm to 600 mm
for rectangular solid timber in the range 1.0 ≥ k
h
≤
l
h
1.3 i.e. for depths 150 mm to 40 mm
Thickness,
mm
Characteristic density (kg/m
3
) and strength (N/mm
2
) values
Density
Bending
Tension
Compression
Panel Shear
Planar Shear
f
m
f
1
f
c
f
v
f
r
ρ
k
mod
0
90
0
90
0
90
> 6 to 10
550
18.0
9.0
9.9
7.2
15.9
12.9
6.8
1.0
> 10 to 18
550
16.4
8.2
9.4
7.0
15.4
12.7
6.8
1.0
> 18 to 25
550
14.8
7.4
9.0
6.8
14.8
12.4
6.8
1.0
Thickness,
mm
Mean stiffness values (N/mm
2
)
Bending
` Tension
Compression
Pane
l Shear
Planar Shear
E
m
E
1
E
c
G
v
G
r
k
mod
0
90
0
90
0
90
> 6 to 10
4930
1980
3800
3000
3800
3000
1080
50
> 10 to 18
4930
1980
3800
3000
3800
3000
1080
50
> 18 to 25
4930
1980
3800
3000
3800
3000
1080
50
Table 19.8 Characteristic strength values for OSB/3 (BSI, 2001). Permission to reproduce extracts from BS EN 12369-1 is granted by BSI
