detail will produce equipment 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 (see 6.2).
3.3 Dissimilar metals. All dissimilar metals throughout the trailer chassis shall be insulated
from one another to preclude galvanic or electrolytic action. Insulation shall be by a coat of
epoxy, chromate, or alkaline-resistant, mylar barrier, electrical tapes, alumastic compound, or
other effective means that prevent direct contact. Dissimilar metals are defined in MIL-STD-889
3.4 Material. Material shall be as specified herein and, for size 9 chassis as shown on the
drawings. Materials not specified shall be selected by the contractor as being compatible with
the intended use in accordance with the engineering standards of the trailer and construction
equipment industry and as set forth in the following industry standardization publications:
Society of Automotive Engineers (SAE).
Truck Trailer Manufacturers Association (TTMA).
The Maintenance Council - ATA (TMC-ATA).
Tire and Rim Association (TRA).
Friction Materials Standards Institute (FSMI).
Industrial Fasteners Institute (IFI).
American Welding Society (AWS).
Forging Idustry Association (FIA).
American Society for Testing and Materials (ASTM)
American National Standards Institute (ANSI).
Rubber products furnished shall be not more than two (2) years from date of cure of the rubber to
date of acceptance of the trailer chassis by the Governement. Threaded parts shall be in
accordance with SAE J370, SAE J371, and Industrial Fasteners Institute Standards.
3.4.1 Material design criteria. The stresses in the load carrying members of the equipment,
both as a plant jacked up for operation and as a trailer chassis prepared for road transport, shall
not exceed 50 percent of the materials yield point (YP) strength under static conditions. A
calculated stress analysis of the trailer chassis of the plant units shall be furnished. This analysis
shall include calculations and diagrams for the following:
a. The gross vehicle weight rating (GVWR) load distribution diagram of each chassis,
blocked and on wheels.
b. The vertical shear diagram for the length of each chassis, blocked and on wheels.
c. The bending moment diagram for the length of each chassis, blocked and on wheels.