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 (g) Self-tapping screws shall not have a diameter smaller than
a no. 14 screw while the minimum diameter of a self-drilling and
self-tapping type shall be equal to or greater than a No. 12 screw.
Automatic-welded studs shall be shouldered type and have a shank diameter of
at least 3/16 inch. Fasteners for use with power actuated tools shall have
a shank diameter of not less than 1/2 inch. Blind rivets shall be stainless
steel type and have a minimum diameter of 1/8 inch. Rivets shall be
threaded stem type if used for other than fastening trim and if of the
hollow type shall have closed ends. Bolts shall not be less than 1/4 inch
in diameter and will be provided with suitable nuts and washers.
(h) If suction loads dictate, provide oversized washers with a
maximum outside diameter of 2 inches or 22-gauge thick metal strip along
each valley.
c. Preparation of Partial Blast Analysis. A partial blast analysis of
a pre-engineered building shall be performed by the design engineer. This
analysis shall include the determination of the minimum size of the roof and
wall panels which is included in the design specifications and the design of
the building foundation and floor slab. The foundation and floor slab shall
be designed monolithically and have a minimum thickness as previously
stated. Slab shall be designed for a foundation load equal to either 1.3
times the yield capacity of the building roof equivalent blast load or the
static roof and floor loads listed below. Quite often the foundation below
the buildings columns must be thickened to distribute the column loads. For
the blast analysis of the building foundation and floor slab, the dynamic
capacity of the soil below the foundation slab can conservatively be assumed
to be equal to twice the static soil capacity. The resistance of the roof
of the building can be determined in accordance with the procedures given in
the report by Tseng, et al., titled Design Charts for Cold-Formed Steel
Panels and Wide-Flange Beams Subjected to Blast Loads. The criteria given
in this report have been updated by the results of a series of
pre-engineered building tests which have been reported in the report titled
Blast Capacity Evaluation of Pre-Engineered Buildings, by Stea, et al. The
front panel of the building is designed in the same manner as the roof
panel. The blast loads for determining the capacities of the roof and wall
panels can be determined from NAVFAC P-397.
d. Pre-Engineered Building Design. Design of the pre-engineered
building shall be performed by the pre-engineered building manufacturer
using the following static design loads. Conventional stresses as listed in
the report titled Specification for the Design, Fabrication and Erection of
Structural Steel for Buildings, Manual of Steel Construction shall be used
in combination with these loads.
(1) Floor live loads shall be as specified in American National
Standard Institute standard A58.1-82, Minimum Design Loads for Buildings
and Other Structures (hereafter referred to as ANSI A58.1), but not less
than 150 pounds per square foot.
(2) Roof live loads shall be as specified ANSI-58.1.
(3) Dead loads are based on the materials of construction.
2.08-240
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