6.2.7. The deadmen are to be butted together at the tank center,
on each side of the tank when multiple sections are used.
6.2.8. Use one U-bolt per strap end and only one strap per
U-bolt.
6.3. ANCHOR SLAB
6.3.1. An anchor slab is typically a reinforced concrete base.
6.3.2. The total length of the slab must be at least the same as
the length of the tank.
6.3.3. The minimum slab thickness is 8 inches.
6.3.4. The width of the slab depends on the tank diameter. The
slab must extend a minimum of 18 inches [12 inches for 4-foot-
diameter tanks] beyond each side of the tank.
6.3.5.
Refer to TABLE 6-2 and FIGURE 6-1
for anchor-point
dimensions.
6.3.6. Provide a separate anchor point for each hold-down strap.
6.3.7. All anchor points must be engineered to withstand the
tank’s buoyancy forces.
6.3.8. When using a concrete base slab, allow sufficient depth in
the excavation for 12 inches of bedding material below the tank.
(See FIGURE 6-1.)
FIGURE 6-1
TABLE 6-2
Tank
Diameter
4’
6’
8’
10’
12’
“A”
24”
35”
43”
57”
58”
Anchoring Dimensions
“B”
18”
23”
31”
45”
50”
“C”
12”
13”
15”
15”
23”
“E”
Min.
27”
42”
52”
69”
87”
“E”
Max.
30”
48”
58”
75”
93”
“D”
8’ - 4 1/4”
12’ - 1”
15’ - 1”
18’ - 8 3/4”
22’ - 6 3/4”
Position Strap Clip
at Tank Top
D
C
B
E
A
12"
Slab
Deadman
Clips
Typical Anchoring
Configuration
14
TABLE 6-1
6.1.7. Tanks of 10-foot diameter with a capacity of 30,000 gallons
or larger may require larger deadmen than those
in TABLE 6-1,
depending on burial depth, to offset buoyancy. Contact technical
support at Xerxes Minneapolis for further information.
6.1.8. Lay the deadmen in the excavation parallel to the tank
and outside of the tank “shadow.”
(See FIGURE 5-3.)
6.1.9. In multiple tank installations with deadmen:
• each tank will have its own set of deadmen (one deadman may
be used between two tanks if the deadman is double in width);
• a separate anchor point must be provided for each hold-
down strap;
• the minimum spacing between tanks must be no less than
twice the width of a single deadman.
6.2. XERXES DEADMAN ANCHORS
6.2.1. A Xerxes-supplied deadman is pre-engineered and sized
to the tank ordered. As with any deadman, water-table height,
number of attached collar risers and burial depth must be
considered.
6.2.2. Placement of a Xerxes deadman is the same as a
standard deadman.
(See FIGURE 6-1.)
6.2.3. A Xerxes deadman is supplied with 3/4-inch-diameter,
plated U-bolts. These bolts protrude up through the slots in the
deadman and are held in place with cotter pins.
Only use the U-bolts when lifting and positioning the
deadmen. A spreader bar may be required to lift longer
sections of deadmen. Use guy ropes to guide the deadmen
when lifting. Failure to do so could result in death or
serious injury.
6.2.4. The U-bolts can be moved and positioned to match the
hold-down strap locations on the tank (marked by arrowhead
symbols
).
6.2.5. When using these deadman anchors in man-out-of-hole
strapping applications, align the U-bolts with the proper ribs
before setting them in the hole.
6.2.6. Care should be taken to keep backfill from entering the
U-bolt slot until final adjustment is made.
4’
6’
8’
10’
12’
Typical
Deadman Dimensions
(Width x Depth)
6” x 6”
12” x 12”
12” x 12”
18” x 12”
36” x 8”
Tank Diameter
