Table 1-3.Recoverability Codes
Designed for specific purpose of being readily erected, disassembled, stored, and
reused. includes tentage.
Not specifically designed to be dismantled and relocated, but could be, with
considerable effort and loss of parts. Rigid-frame building included.
A structure not designed to provide relocatability features or one where the cost
of recovery of the shelter exceeds 50% of the initial procurement cost. Bolted
tanks and steel bridges included.
Those temporary structures having low acquisition and erection costs which are
not designed for relocation and reuse and may be left on site or destroyed, such as
EXCAVATIONS AND SHORING
Working in, working around. or directing a crew in
a trenching or excavation job can be dangerous. The
following paragraphs will give you some of the
accepted engineering requirements and practices.
Think safety, not only for your workers but for the
other persons that may encounter your work area.
Preplanning before starting any excavation will
save time and avoid costly mistakes. Give attention to
personal safety equipment, underground utility
installations, personnel/vehicular traffic interruptions,
security, and public safety. Make sure your crew is
aware of the safe working area around a specific piece
of excavating equipment. Set up daily inspections of
excavations for possible cave-ins or slides. Moving
ground must be guarded by a shoring system, sloping
of the ground, or some other equivalent means.
Excavated or other materials must not be stored closer
than 2 feet from the edge.
When crews are working in trenches 4 feet or more
in depth, access into or exits out of excavations should
be by ramps, ladders. stairways. or hoists. Crew
members should not jump into trenches or use bracing
as a stairway.
Banks more than 5 feet high must be shored or laid
back to a stable slope, or some other equivalent means
of protection must be provided where crew members
may be exposed to moving ground or cave-ins. Refer to
figure 1-6 as a guide in sloping of banks.
Sides of trenches in unstable or soft material, 5 feet
in depth, are required to be shored, sheeted, braced,
sloped, or otherwise supported by sufficient strength to
protect the crew members working within them.
Sides oftrenches in hard or compact soil, including
embankments, must be shored or otherwise supported
when the trench is more than 5 feet in depth and 8 feet
or more in length.
The determination of the angle of repose and
design of the supporting system must be based on
careful evaluation of many features: depth or cut;
possible variation in water content of the material
while the excavation is open; anticipated changes in
materials from exposure to air, sun, water, or freezing;
loading imposed by structures, equipment, overlying