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 7.4.6
Blind rivets shall be stainless steel with 1/8 inch nominal
diameter shank. Rivets shall be threaded stem type if used for
other than fastening of trim. Rivets with hollow stems shall have
closed ends.
7.4.7
Bolts shall not be less than 1/4 inch diameter, shoulders or plain
shank as required with proper nuts.
7.4.8
Provide overside washers with an outside diameter of 1 inch at each
fastener or a 22-gauge thick metal strip along each valley of the
panel to negate pull-out of the panel around the fasteners.
5.
EXAMPLE PROBLEMS.
a.
Masonry Wall Design.
Problem:
Design midspan of a joint reinforced masonry wall supported by
steel columns for an exterior blast load. Use hollow concrete
masonry units.
Given:
(1) Clear span.
(2) Pressure-time loading.
(3) Deflection criteria.
Solution:
(1)
Select masonry unit size and reinforcing steel.
(2)
Calculate dynamic properties of materials.
(3)
Calculate ultimate moment capacity of the section.
(4)
Find ultimate resistance of the wall according to
Section 5-10 of NAVFAC P-397.
(5)
Determine Em and Ia of the section using Table 29 and
Equations (125), (130), and (131)
(6)
Find equivalent stiffness from Table 7.
(7)
Calculate equivalent elastic deflection.
(8)
Determine load-mass factor from Section 6-6 of NAVFAC
P-397.
(9)
Calculate effective mass of the wall section using Table
27.
(10) Using Equation (1), find natural period of wall.
2.08-248
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