Use and Care Manual

5
NO MATTER WHAT METHOD IS USED, IT IS CRITICAL
THAT THE ANCHOR BE PROPERLY LOCKED BEFORE
TYING OFF THE OBJECT TO BE ANCHORED.
An anchor not properly locked prior to attaching will result
in signicant pull out before the anchor self locks. Obvi-
ously this is not desired.
Failure to install and lock the anchor at the correct angle
will result in the anchor cable cutting through the soil until
the angles equalize. This will cause slack in guy lines, also
not desired.
SPECIAL SOILS
CONSIDERATIONS
SOFT SOILS
In areas where the soil proves to be softer than normal,
steps should be taken to assure the capacity of the anchor.
Proof-loading is especially useful in soft soils. Guesswork
as to the capacity is eliminated. The installer will know im-
mediately if the anchor point is adequate or if further steps
are necessary. Backlling and tamping the hole behind the
anchor will yield somewhat higher capacity in most soft
soils. Fill and tamp the hole in 3” lifts prior to anchor locking
the anchor. Another option is to drive the anchor deeper in
an effort to penetrate a harder layer of soil. Larger anchors
may need to be placed to achieve the required load. As a
last resort a number of anchors may be placed in a cluster
and bridled together to form one point.
HARD SOILS AND ROCK
If excessive resistance to driving occurs it may be neces-
sary to drill a hole for anchor placement. If the anchor
stops moving and is subjected to excessive force (espe-
cially from power equipment) metal fatigue can occur and
the anchor body can fracture. The DUCKBILL’” Anchor
may be placed in a pre-drilled hole in hard dirt or rocky
material, and achieve very good results. Hand augers and
gasoline or hydraulic powered earth drills can be used to
form the hole. A gasoline powered breaker/drill is very use-
ful due to the fact that it performs both drilling and driving
operations.
CLEARANCE HOLE DIAMETERS
& HARD SOIL PILOT HOLE
DIAMETERS
Installation of Duckbill Anchors in hard soils can be greatly
helped by the use of a pilot hole. Typically, the pilot hole
has no signicant affect on the holding power of the an-
chor. There are many acceptable mehods of drilling pilot
holes and many manufacturers of equipment to do so.
Recommended hard soil pilot hold diameters and clear-
ance hole diameters are charted below.
Model Clearance Hole
Diameter
Minimum Pilot
Hole Diameter
for Hard Soil
40-DB 1.0” 0.75”
68-DB 1.50” 1.25”
88-DB 2.25” 2.00”
138-DB
2.75”
2.50”