Civil engineer guide to fighting positions, shelters, obstacles

AFH 10-222 Volume 14 1 August 2008 140
A2.2.2. Concrete. Steel reinforced concrete provides excellent protection
against direct fire, indirect fire, and fragmentation. However, placement of
concrete structures is important, as they are subject to fail when a large detonation
occurs nearby and can themselves become secondary fragmentation.
A2.2.3. Steel. Steel provides excellent protection against fragmentation resulting
from direct- and indirect-fired weapons. Obstacles made from steel
can be effectively utilized to resist the effects of many types of weapons.
A2.2.4. Rocks. Rocks can be effective against direct and indirect fire and
fragmentation. Hard rocks can deform, stop, or deflect projectiles. Small
rocks and gravel can be used similar to soil and is less susceptible to moisture.
A disadvantage of using rocks is that they can become weakened after
multiple hits or become projectiles if dislodged by blast or upon impact.
A2.2.5. Brick and Masonry. Brick and masonry have similar characteristics
of rocks against penetration and fragmentation effects. However, unreinforced
brick and masonry do not afford the same protection as concrete because
of less density.
A2.2.6. Snow and Ice. Snow and ice may be the only material available at
some locations and may be effective against small caliber weapons and
nearby blast when used in mass or in combination with frozen soil.
A2.2.7. Lumber and Timber. Wood (e.g., lumber, plywood, timber) has
limited value in stopping projectiles or fragments due to its low density. This
material needs to be very thick to stop small caliber and anti-tank weapons.
A2.2.8. Miscellaneous Materials. If available, miscellaneous materials, such
as landing mats, cargo pallets, steel containers, and culverts provide some
degree of protection from penetrating projectiles and fragmentation effects.
A2.3. Expedient Materials for Protection Against Explosions. Table A2.1,
extracted from FM 5-103, contains thicknesses of materials needed to provide
adequate protection from nearby explosions. In some cases, engineers must
use whatever materials are available at the site to devise and construct structures
needed to contain these shielding materials.