Civil Engineering Reference
In-Depth Information
Table 20.2
Section Properties and Allowable Stresses for Certain Sizes of Plyform (Courtesy of the American Plywood Association)
Properties for stress applied
Properties for stress applied
parallel with face grain
perpendicular to face grain
Approximate
Moment of
Effective section
Rolling shear
Moment of
Effective section
Rolling shear
Thickness
weight
inertia,
I
modulus,
K
s
constant, lb/
Q
inertia,
I
modulus,
K
s
constant, lb/
Q
(in.
4
/ft)
(in.
3
/ft)
(in.
2
/ft)
(in.
4
/ft)
(in.
3
/ft)
(in.
2
/ft)
(inches)
(psf)
Class I
1
2
1.5
0.077
0.268
5.127
0.035
0.167
2.919
5
8
1.8
0.130
0.358
6.427
0.064
0.250
3.692
3
4
2.2
0.199
0.455
7.854
0.136
0.415
4.565
7
8
2.6
0.280
0.553
8.204
0.230
0.581
5.418
1
3.0
0.427
0.737
8.871
0.373
0.798
7.242
1
8
3.3
0.554
0.894
9.872
0.530
0.986
8.566
Class II
1
2
1.5
0.075
0.267
4.868
0.029
0.182
2.671
5
8
1.8
0.130
0.357
6.463
0.053
0.320
3.890
3
4
2.2
0.198
0.455
7.892
0.111
0.530
4.814
7
8
2.6
0.280
0.553
8.031
0.186
0.742
5.716
1
3.0
0.421
0.754
8.614
0.301
1.020
7.645
1
8
3.3
0.566
0.869
9.571
0.429
1.260
9.032
Structural I
1
2
1.5
0.078
0.271
5.166
0.042
0.229
3.076
5
8
1.8
0.131
0.361
6.526
0.077
0.343
3.887
3
4
2.2
0.202
0.464
7.926
0.162
0.570
4.812
7
8
2.6
0.288
0.569
7.539
0.275
0.798
6.242
1
3.0
0.479
0.827
7.978
0.445
1.098
7.639
1
8
3.3
0.623
0.955
8.841
0.634
1.356
9.031
Note:
All properties are adjusted to account for reduced effectiveness of plies with grain perpendicular to applied stress.
