3.1.2 Towing compatibility. Unless otherwise specified, the semitrailer shall be compatible
for coupling, towing, maneuvering, spotting, and dumping under all conditions specified herein
when coupled to a commercial truck-tractor that is unmodified, except for installation of power
hoist components. Commercial truck-tractors shall include those specified in KKK-T-2108,
KKK-T-2109, and MIL-C-52895, MIL-T-52901. The empty height of the underside of the upper
fifth wheel plate above level ground, when the semitrailer is level, shall coincide with the height
of the truck-tractor, having a rating equal to or exceeding the gross combination weight rating
(GCWR) of the truck-tractor and semitrailer with payload. Each semitrailer shall be compatible
with fore and aft rocking lower fifth wheels. When and as specified by the procuring activity
(see 6.2, 184.108.40.206, and 6.4):
The dump semitrailer shall be matched to the user's prime mover (truck-tractor) to
insure complete, compatable, powered combination vehicle(s); or
The dump semitrailer shall be furnished coupled to a new prime mover as a
complete, compatable, powered combination vehicle package.
3.1.3 Material design criteria. The stresses in the load carrying members of the semitrailer,
with the payload as specified in table I and the applicable specification sheet, shall not exceed
33 percent of the yield point (YP) strength under static conditions. A calculated stress analysis
of the semitrailer shall be furnished. This analysis shall include calculations and diagrams for
The GVWR load distribution diagram of the semitrailer.
The vertical shear diagram for the length of the semitrailer.
The bending moment diagram for the length of the semitrailer.
3.1.4 First-article semitrailer. The contractor shall furnish a semitrailer of each size for
examination and test within the time frame specified (see 6.2) to prove that his production
methods and choice of design detail will produce semitrailers that comply with the requirements
of this specification. Examination and tests shall be as specified in Section 4, and unless
otherwise specified herein, all examinations and tests shall be conducted by the contractor
subject to surveillance and approval by the Government (see 6.3). When specified (see 6.2), the
Government will conduct any or all of the first-article examination and tests, as specified
3.2 Special requirement. Semitrailers shall meet the following special requirements as
3.2.1 Electromagnetic interference. When specified (see 6.2), semitrailers supplied with an
auxiliary engine (see 3.8) shall have electronmagnetic interference emission and susceptibility
characteristics conforming to SAE J551.
3.2.2 Treatment, painting, and data plates. As specified by the procuring activity for the
appropriate service (see 6.2), treatment, painting, and data plates shall be in accordance with
MIL-STD-1223 and as specified herein. Inaccessible areas of the semitrailer, and truck shall be