used. The depth of deck units will not be less than
1 inches (38mm).
diaphragms, as indicated in Figure 7-56.
(b) Connections at ends and at supporting
chord reinforcement and connection details are
Refer to Type A and Type B details,
shown in Figure 7-57.
Paragraphs 7-7e(2) and 7-7e(3).
(4) Acceptance criteria.
Connections at marginal supports.
Marginal welds for all types of steel deck diaphragms
Reinforced concrete diaphragms for
Performance Objective 1A shall be designed with the
will be spaced as follows:
response reduction factor, R, in Table 7-1, based on
for puddle welds
the building' structural systems.
(b) For enhanced performance objectives,
35,000 t1 + t 2
reinforced concrete diaphragms shall be considered
as force-controlled rigid elements, and the demand /
capacity ratio in shear shall not exceed 1.25.
200,000 t1 + t 2
Steel Deck Diaphragms.
for fillet welds and seam welds
(1) General design criteria. The following
criteria will be used to design steel deck diaphragms.
The three general categories of steel deck diaphragms
are Type A, Type B, and decks with concrete fill.
Design data from industry sources such as the Steel
Deck Institute and the Research Reports of the
International Conference of Building Officials may
be used subject to the approval of the Agency
aw = spacing of marginal welds in feet (m).
thickness of flat sheet elements in
(a) Typical deck units and fastenings. Deck
inches (mm) (22-gauge minimum).
units will be composed of a single fluted sheet or a
t'2 = effective thickness of fluted elements
combination of two or more sheets fastened together
in inches (mm).
with welds. The special attachments used for field
attachment of steel decks are shown in Figure 7-58.
average shear in diaphragm over
In addition to those shown, standard fillet (1/8-inch
length L1, in pounds per foot (N/m).
by 1-inch) (3mm by 25 mm) and butt welds are also