Section I. TANK SITE AND SOIL TEST
2-1. Tank Site
water table should be more than 6 feet below the
a. The tank site should be placed in an area that is
surface. Avoid marshy areas, river banks subject to
flooding, and other sites with poor or undependable
not congested with other facilities. Do not locate the
drainage. Prior to site preparation, refer TM 5-302, TM
tank in drainage areas above critical installations. Do
5-335, and TM 5-349.
not locate the tank (if used for fuel storage) in areas
2-2. Soil Test
containing highly flammable materials.
b. The tank should be erected on soil with a
A positive test is made to estimate bearing capacity of
the soil. Refer to TM 5-330 for the load testing
uniform bearing strength of at least 1800 pounds per
square foot to prevent the tank from sinking or
displacing its foundation.
The site should have
adequate natural drainage. Preferably, the underground
Section II. TANK FOUNDATION
2-3. Foundation Requirements
and a sharp tool, scribe a circle approximately 10 feet
greater in diameter than the tank.
Tank foundations must be stable, with load-bearing
c. Grading. Where the site is level and subsoil has
strength of at least 1800 pounds per square foot. Lay
adequate bearing strength, proceed as follows: (1)
out and grade the foundation so that there is adequate
Remove the topsoil to a depth of about 6 inches and
drainage away from the tank. Uneven settlement of the
replace it with clean sand, gravel, crushed rock, or
filled thin-wall tanks and corrosion of tank bottom results
similar granular material, except cinders (a 1-inch top
Special foundation treatment is often
layer of sand is desirable). Compact the material in
2-4. Construction of Foundation
layers to a grade about 8 inches above the surrounding
ground surface (fig. 2-1). Use a slope ration of about 1:
Prior to starting foundation
1 for the outer slopes.
preparation, refer to TM 5-302, TM 5-335, and TM 5-
Cinders must not be used for
b. Layout. After selecting the tank site (para 2-1),
foundation material because of the
stake out the tank foundation. Drive a stake in the
corrosive action of cinders when
center of the proposed tank site. With a tape or line
water or dampness is present.
Figure 2-1. Sectional view of foundation.
(2) Carefully check the grade of the
The tank foundation must be level to prevent binding of
foundation with an engineer level as shown in figure 2-2.
staves and deck plates as the tank is erected.