2-3 DESIGN CRITERIA – Pipe Section Properties
As in the design of other structural components, the shape of the pipe
profile helps determine how it will perform in the pipe/soil structure.
Pipe properties include the moment of inertia of the wall profile (I),
distance from the inside diameter to the neutral axis (c), and the section
area of a longitudinal section (As). Pipe stiffness (PS) is
a measure of the flexibility of a prescribed length of pipe and is measured
in the laboratory by gauging the force required to deflect the pipe 5%
of its inside diameter. Although substituted directly in the design equations,
PS is primarily a quality check and should not be interpreted to be a
limiting pipe property. Section properties of Sure-Lok® and Hi-Q®
are shown in Table 2-1; properties for AASHTO pipe are shown in Table
2-2.
Table 2-1 – Section Properties for Sure-Lok®
and Hi-Q® Pipe
| Inside Diameter, ID |
Outside Diameter, OD |
Pipe Stiffness, PS |
Section Area,
As |
Distance from
Inside Diameter to Neutral Axis, c |
Moment of
Inertia, I |
| in. |
mm |
in. |
mm |
pii |
N/m/mm |
in2/in |
mm2/mm |
in. |
mm |
in4/in |
mm4/mm |
|
4
|
100
|
4.7
|
119
|
50
|
340
|
0.088
|
2.235
|
0.139
|
3.531
|
0.002
|
32.774
|
|
6
|
150
|
7.0
|
178
|
50
|
340
|
0.117
|
2.974
|
0.192
|
4.876
|
0.003
|
54.373
|
|
8
|
200
|
9.5
|
241
|
50
|
340
|
0.137
|
3.470
|
0.297
|
7.535
|
0.009
|
142.567
|
|
10
|
250
|
12.0
|
305
|
50
|
340
|
0.152
|
3.863
|
0.393
|
9.970
|
0.019
|
303.604
|
|
12
|
300
|
14.2
|
361
|
50
|
345
|
0.198
|
5.024
|
0.436
|
11.076
|
0.032
|
523.214
|
|
15
|
375
|
17.7
|
450
|
42
|
290
|
0.230
|
5.847
|
0.508
|
12.893
|
0.055
|
901.594
|
|
18
|
450
|
21.5
|
546
|
40
|
275
|
0.251
|
6.378
|
0.689
|
17.508
|
0.100
|
1636.928
|
|
24
|
600
|
28.4
|
721
|
34
|
235
|
0.308
|
7.831
|
0.857
|
21.778
|
0.184
|
3012.178
|
|
30
|
750
|
36.0
|
914
|
28
|
195
|
0.384
|
9.756
|
1.033
|
26.248
|
0.322
|
5269.812
|
|
36
|
900
|
41.4
|
1052
|
22
|
150
|
0.375
|
9.525
|
1.020
|
25.908
|
0.356
|
5837.072
|
|
42
|
1050
|
48.0
|
1219
|
20
|
140
|
0.422
|
10.719
|
1.110
|
28.194
|
0.543
|
8898.176
|
|
48
|
1200
|
55.0
|
1397
|
18
|
125
|
0.440
|
11.176
|
1.150
|
29.210
|
0.543
|
8898.176
|
|
54
|
1350
|
61.0
|
1549
|
16
|
110
|
0.473
|
12.014
|
1.250
|
31.750
|
0.827
|
13552.102
|
|
60
|
1500
|
67.3
|
1709
|
14
|
97
|
0.538
|
13.665
|
1.370
|
34.798
|
1.008
|
16518.161
|
Table 2-2 – Section Properties for AASHTO Pipe
| Inside Diameter, ID |
Outside Diameter, OD |
Pipe Stiffness, PS |
Section Area,
As |
Distance from Inside Diameter
to Neutral Axis, c |
Moment of
Inertia, I |
| in. |
mm |
in. |
mm |
pii |
N/m/mm |
in2/in |
mm2/mm |
in. |
mm |
in4/in |
mm4/mm |
|
3
|
75
|
3.6
|
91
|
35
|
240
|
0.0448
|
1.138
|
0.1528
|
3.881
|
0.0004
|
6.736
|
|
4
|
100
|
4.6
|
118
|
35
|
240
|
0.0568
|
1.444
|
0.1917
|
4.868
|
0.0007
|
10.810
|
|
6
|
150
|
7.0
|
178
|
35
|
240
|
0.0837
|
2.125
|
0.3158
|
8.022
|
0.0021
|
34.966
|
|
8
|
200
|
9.5
|
241
|
35
|
240
|
0.1044
|
2.653
|
0.4345
|
11.035
|
0.0054
|
87.673
|
|
10
|
250
|
12.0
|
305
|
35
|
240
|
0.1117
|
2.837
|
0.5319
|
13.510
|
0.0120
|
196.727
|
|
12
|
300
|
14.2
|
361
|
50
|
345
|
0.2084
|
5.292
|
0.6136
|
15.586
|
0.0286
|
468.272
|
|
15
|
375
|
17.7
|
450
|
42
|
290
|
0.1958
|
4.972
|
0.7239
|
18.386
|
0.0419
|
687.370
|
|
18
|
450
|
21.5
|
546
|
40
|
275
|
0.2335
|
5.931
|
1.0098
|
25.648
|
0.0784
|
1284.143
|
|
24
|
600
|
28.4
|
721
|
34
|
235
|
0.2906
|
7.380
|
1.2329
|
31.315
|
0.1478
|
2422.427
|
Pipe similar to Sure-Lok®, Hi-Q® and AASHTO
products but made by other manufacturers may have slightly different section
properties depending on their design. Data for those products should be
obtained from the respective manufacturer for use in this design procedure.
DESIGN CRITERIA
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