Photo By Cynthia McIntyre | A Company, 14th Brigade Engineer Battalion stationed at Joint Base Lewis-McChord, Washington, train at Fort Hunter Liggett, Calif., for an abatis demolition to fell trees. Power poles stand in for trees and are rigged with C-4 explosive to fall in a cross-cross pattern to block a road. A shattered pole remains from the force of the explosion. see less
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Soldiers from A Company,
14th Brigade Engineer
Battalion stationed at
Joint Base Lewis-McChord,
Wash. conducted training
in various demolition techniques
prior to supporting
the 7th Infantry Division’s
Bayonet Focus exercise.
One spectacular blast,
shown at top photo, was
that of rigging a row of
poles with C-4 plastic
explosive so that they fell
in a crisscross pattern to
block a road. Called an
abatis demolition, the timber-
cutting charges consisted
of one lower on the
“tree” at a 45 degree angle
to direct it into the road,
and a kicker charge 10 or
so feet high. A timed fuse
was also set as a backup
before the demo area was
vacated.
After the C-4 blocks
were fastened to the poles
and wired to M23 blasting
caps, the detonation cord
attached at the other end
to a shock tube was unspooled
to a safe point.
Mere heat or flame won’t
set off the C-4; it takes a
certain type of pressure
and spark from the shock
tube to do that.
Shouting “Fire in the
hole” three times gave a
few seconds’ warning before
the pin was extracted
from the tube, the plunger
pressed in and given a
quarter-turn, then firmly
pulled out. BOOM!
