Chapter 2 MAINTENANCE INSTRUCTIONS

TM 5-5430-209-12

CHAPTER 2

MAINTENANCE INSTRUCTIONS

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

procedure.

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

in leakage.

Special foundation treatment is often

layer of sand is desirable). Compact the material in

necessary.

2-4. Construction of Foundation

layers to a grade about 8 inches above the surrounding

a. Preparation.

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-

CAUTION

349.

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.

2-1