The sprung GVW load distribution diagrams
The vertical shear diagram for the length of the vehicle
The bending moment diagram for the length of the vehicle
The loads, sections, shear, and bending members that carry maximum shear and
moment, to include the analysis of the stresses in attaching weldments or other
The loads, sections, shear, and bending moment diagrams at kingpin and rear under
structure subframe members, and for the drop section when drop frame semitrailers are
The load, section, shear, and bending moment diagrams for the most critical
crossmember, to include the analysis of stresses in attaching weldments or other
The loads, sections, and stresses in members that carry maximum compression
Consider all potential structural loadings
List all assumptions and references utilized to provide required data.
3.6 Suspension system. Each component of the suspension system shall have a rated
capacity at least equal to the load imposed, measured at the ground, when the semitrailer is
loaded with its rated payload (see 3.2.3). Clearances shall be sufficient to prevent interference
between tires and any other part of the semitrailer under the operating conditions specified
3.7 Tandem axle. The semitrailer shall be furnished with tandem axles. Axle ratings shall
be at least equal to the load imposed on each axle measured at the ground, with the semitrailer
loaded with rated payload as specified in 3.2.3. The wheel bearings and axle spindles shall be oil
lubricated. The oil viscosity shall be in accordance with the manufacturer's recommendations.
The hubs shall be fitted with seals. The hub caps shall have a window and shall incorporate
provisions for replenishing the oil supply. The hub caps shall incorporate provisions for venting
or equivalent method of withstanding internal pressure buildup without leakage.
* 3.8 Wheels, rims, tires, and tubes. The semitrailer shall be equipped with dual wheels, rims
and tires. The rim and tire ratings shall conform to Tire and Rim Association or European Tyre
and Rim Technical Organisation recommendations for the type and size of tires furnished. Rim
sizes shall be the same for all wheels on the semitrailer. Tires size and load range (ply rating)
shall be the same for all tires on the semitrailer. Multi-piece rims shall not be furnished. When
specified (see 6.2), disc type wheels shall be furnished.
* 3.8.1 Tires. Tires shall be tubeless type with highway tread. Tires shall be of the steel
belted radial type. Tires shall have a rated capacity at least equal to the load imposed on each
tire, measured at each wheel, at the ground, with the semitrailer loaded with rated payload. Tires