TABLE I. Road test profile, 6,000 mi.
Improved secondary road
1/ Level to slightly hilly.
3.2.1 Payload and distribution. The semitrailer shall be capable of transporting the rated
payload without permanent deformation to the frame or gooseneck, while operating at the terrain
profile specified in table I, with the load distribution specified in table II. The semitrailer shall be
suitable for the concentrated, pin point and localized stresses caused by trucks, track pads and
wheels, and any other normally distributed loads on the platform caused by the full range of
intended use specified in Appendix A. Maximum allowable kingpin load shall not exceed
44,730 pounds (lb) with the semitrailer fully loaded.
TABLE II. Payload distribution.
Length, feet (ft) 1/
Width, inches (in) 2/
1/ Length of evenly distributed payload in center of load space
2/ Width of each crawler track, centered on load space.
3.2.2 Environmental conditions. The semitrailer shall be operational after a 24 hour (hr) cold
soak in ambient temperature ranging from minus (-) 25 degrees Fahrenheit (°F) to plus
(+) 120°F, capable of operating in hot, humid tropical environments and dry, dusty conditions,
and capable of being stored for extended periods in temperatures ranging from -28 to +160°F
3.2.3 Reliability. The reliability of the semitrailer shall have a design goal requirement of
6,000 mean miles between failure (MMBF) as specified in 3.2. For calculation of MMBF, a
failure shall exist when the semitrailer prevents operations, reduces performance below essential
levels, indicates that further operation would be unsafe, or indicates that further operations might
result in extensive damage to the equipment. Any of these conditions that cannot be corrected by
the crew in 1 hr using basic issue items (BII) that are carried on the truck-tractor or the
semitrailer is considered to be a failure. Maintenance and human induced failures are excluded.