FLOOD06430

• County: Statewide
• Basin: Statewide
• Title: Conduits, Culverts and Pipes
• Date: 3/3/1969
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

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EM 1110-2-2902
Change 1
28 Jul 70

ing capacity of the pipe. Plate 11 illustrates types of beddings of dih'erent quality for rigid pipes
subject to loadings under ditch conditions. Plate 12 shows similar information for loadings under
projection conditions.
b. Load factors. The ratio of the supportinr. strength of a pipe installed for a given bedding
condition to the supporting strength of the same pipe when tested by the three-edge bearing
method is called the "load factor"
The recommended load factors for the various bedding conditions of clay and concrete pipes
installed under ditch conditions are shown in the following tabulation:

Type of Bedding
Ordinary
First Class
Concrete Cradle

Loa.d Faetor
1.6
1.9
2.5

* Load factors for the projection condition should be computed by the following equation
*adopted from reference (11) :

F, = 1.431

~if

-1:

. __ _ _ h __ __ _ __ _ _ _ _ _ _ _ _ _ _ (26)

,"
X,. and X. are as listed below:

The parameters

Project1'oll '.-atio, p

x. Co1tef'efe cradl~
0.150
0.743
0.856
0.811
0.678
0.638

X. Other projection bedding
o
0.217
0.428
0.594
0.655
0.638

*

o
0.3
0.5
0.7
0.9
1.0

Type of projection beddin.g
Impermissible
Ordinary
First Class
Concrete Cradle

Valu. of X,
1.310
0.840
0.70'1
0.605

In application, the load factors multiplied by the strength values as tabulated in the pertin-
ent A.S.T.M. specification will give the supporting strength of the pipe ih the installed condi-
tion. For reinforced concrete pipe, the tabulated test load value which produces a 0.01 inch crack
should be used in this calculation. In computing the allowable load on clay or concrete pipe, the
supporting strength (product of tabulated test load value and applicable load factor) should be
divided by a safety factor of 2 for installations under levees and similar critical locations.
c. Design Procedu1'es for Precast Concrete Pipe. Compute vertical load, W.. by equations of
* paragraph ,J using Case 1 only. Compute the required "D-load" from the equation

D-Ioad = W. x SF
IDxF, '-..--- -
where W. = vertical load in lbs. per lin. ft. of pipe
SF = safety factor = 2.0
ID = inside diameter of pipe, in feet
F, - load factor

. _ __. _ _ _._ __ _ __ ___.__ _ _ _ __ _ _ _ _ _ (27)

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