TM 5-820-4/AFM 88-5, Chap 4
structed of steel or aluminum. For the metal cul-
mum size that can be used for a specific installation.
verts, different kinds of coatings and linings are
c. The selection of culvert materials to withstand
available for improvement of durability and hydrau-
deterioration from corrosion or abrasion will be
lic characteristics. The design of economical culverts
based on the following considerations:
involves consideration of many factors relating to re-
(1) Rigid culvert is preferable where industrial
quirements of hydrology, hydraulics, physical envi-
wastes, spilled petroleum products, or other sub-
ronment, imposed exterior loads, construction, and
stances harmful to bituminous paving and coating in
maintenance. With the design discharge and gen-
corrugated metal pipe are apt to be present. Con-
eral layout determined, the design requires detailed
crete pipe generally should not be used where soil is
consideration of such hydraulic factors as shape and
more acidic than pH 5.5 or where the fluid carried
slope of approach and exit channels, allowable head
has a pH less than 5.5 or higher than 9.0. Polyethyl-
at entrance (and pending capacity, if appreciable),
ene pipe is unaffected by acidic or alkaline soil condi-
tailwater levels, hydraulic and energy grade lines,
tions. Concrete pipe can be engineered to perform
and erosion potential. A selection from possible
very satisfactorily in the more severe acidic or alka-
alternative designs may depend on practical con-
line environments. Type II or Type V cements
siderations such as minimum acceptable size, avail-
should be used where soils and/or water have a mod-
able materials, local experience concerning corrosion
erate or high sulfate concentration, respectively;
and erosion, and construction and maintenance
criteria are given in Federal Specification SS-C-
aspects. If two or more alternative designs involving
1960/GEN. High-density concrete pipe is recom-
competitive materials of equivalent merit appear to
mended when the culvert will be subject to tidal
be about equal in estimated cost, plans will be devel-
drainage and salt-water spray. Where highly cor-
oped to permit contractor's options or alternate bids,
rosive substances are to be carried, the resistive
so that the least construction cost will result.
qualities of vitrified clay pipe or plastic lined con-
b. In most localities, culvert pipe is available in
crete pipe should be considered.
sizes to 36 inches diameter for plain concrete, 144
(2) Flexible culvert such as corrugated-steel pipe
inches or larger for reinforced concrete, 120 inches
will be galvanized and generally will be bituminous
for standard and helically corrugated metal (plain,
coated for permanent installations. Bituminous coat-
polymer coated, bituminous coated, part paved, and
ing or polymeric coating is recommended for corru-
fully paved interior), 36 inches for asbestos cement
gated steel pipe subjected to stagnant water; where
or clay, and 24 inches for corrugated polyethylene
dense decaying vegetation is present to form organic
pipe. Concrete elliptical in sizes up to 116 x 180
acids; where there is continuous wetness or contin-
inches, concrete arch in sizes up to 107 x 169 inches
uous flow; and in well-drained, normally dry, alkali
and reinforced concrete box sections in sizes from
soils. The polymeric coated pipe is not damaged by
3 x 2 feet to 12 x 12 feet are available. Structural
spilled petroleum products or industrial wastes.
plate, corrugated metal pipe can be fabricated with
Asbestos-fiber treatment with bituminous coated or
diameters from 60 to 312 inches or more. Corru-
a polymeric coated pipe is recommended for corru-
gated metal pipe arches are generally available in
gated-steel pipe subjected to highly corrosive soils,
sizes to 142 by 91 inches, and corrugated, structural
cinder fills, mine drainage, tidal drainage, salt-water
plate pipe arches in spans to 40 feet. Reinforced con-
spray, certain industrial wastes, and other severely
crete vertical oval (elliptical) pipe is available in sizes
corrosive conditions; or where extra-long life is de-
to 87 by 136 inches, and horizontal oval (elliptical)
sirable. Cathodic protection is rarely required for
pipe is available in sizes to 136 by 87 inches. De-
corrugated-steel-pipe installations; in some in-
signs for extra large sizes or for special shapes or
stances, its use may be justified. Corrugated-alu-
structural requirements may be submitted by manu-
minum-alloy pipe, fabricated in all of the shapes and
facturers for approval and fabrication. Short culverts
sizes of the more familiar corrugated-steel pipe,
under sidewalks (not entrances or driveways) may be
evidences corrosion resistance in clear granular
as small as 8 inches in diameter if placed so as to be
materials even when subjected to sea water. Corru-
comparatively free from accumulation of debris or
gated-aluminum pipe will not be installed in soils
ice. Pipe diameters or pipe-arch rises should be not
that are highly acid (pH less than 5) or alkaline (pH
less than 18 inches. A diameter or pipe-arch of not
greater than 9), or in metallic contact with other
less than 24 inches should be used in areas where
metals or metallic deposits, or where known cor-
wind-blown materials such as weeds and sand may
rosive conditions are present or where bacterial cor-
tend to block the waterway. Within the above ranges
rosion is known to exist. Similarly, this type pipe will
of sizes, structural requirements may limit the maxi-
Change 1 3-7
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