Engineer soldier's handbook. Page: 92
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BASIC FIELD MANUAL
SCAP WIRE OR
BORE-HOLE MADE DETONATING
WITH EARTH AUGER X CORD
TIGHT TAMPING -
PRIMER CHARGE -
CHARGE -J ,
FIGURE 103.-Bore hole loaded to blow crater.
calculated to blast through its entire thickness. In attacking
a concrete wall, or a bridge abutment or pier, the entire
amount of explosive is normally concentrated at the mid-
point of the structure, if the width is not more than twice
the thickness. Where the width is more than twice the
thickness, two or more charges are used, each charge being
large enough to shatter the thickness of the wall, and the
distance between successive charges being not greater than
twice the thickness of the structure.
c. Steel.--The effects of an explosion are very localized in
steel. Only that portion of steel which is in close contact
with the explosive charge is cut. A concentrated charge
placed on a steel plate will simply blow a hole in the plate
or dent it directly under the charge. Therefore, if it is
desired to cut a steel plate, the explosive charge must be
distributed over the entire line along which the cut is
desired. Likewise in cutting steel I-beams, built-up girders,
columns, etc., the charge must be distributed so that the
entire cross section of the member will be cut. (See fig.
104.) Charges must never be placed directly opposite one
another on opposite sides of a steel plate or members. When
charges must be placed on opposite sides they should be
3 inches apart along the member.
d. Timber.-External charges for cutting trees, round tim-
bers, etc., are placed around one side of the object (fig. 105).
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United States. War Department. Engineer soldier's handbook., book, June 2, 1943; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc28313/m1/98/: accessed April 20, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.