1.50 times the allowable stress values published by
attached to the deck corrugations, holes placed in the
the Steel Deck Institute, or the International
corrugations, or deck profile in which the fluted
Conference of Building Officials.
elements are placed up so that the fill is keyed with
the deck. If interlocking between the deck and the
m,
ii.
Modification
factors,
for
concrete is not achieved, then mechanical anchorages
enhanced performance objectives shall be taken as
will be required to anchor the fill to the supporting
1.0
for
Performance
Objective
3B;
1.5
for
member, as prescribed in Paragraph 7-7e(2).
Performance Objectives 2A and 2B; and 2.0 for
Performance Objective 1A.
(a)
Concrete as a diaphragm.
If the
diaphragm is loaded and reacted without shear
iii. Steel decking and its attachments
stresses passing through the steel deck or its
are considered to be force-controlled components,
attachments, the diaphragm is a concrete diaphragm
and the strength, QCL, shall be determined as
as described in Paragraph 7-7d. Typical attachment
indicated in Paragraph i above.
details are shown in Figure 7-62, details A and B.
f.
Wood Diaphragms.
(b) Steel deck as a diaphragm.
(1) General design criteria. Wood diaphragms
1. Shear strength. Nominal shear strength
will be designed with reference to Section 12.4 of
of steel deck diaphragm shall be determined in
FEMA 302, and the additional criteria of this section.
accordance with approved analytical procedures or
with test procedures prepared by a licensed design
(2)
Wood diaphragms in concrete and
professional experienced in testing cold-formed steel
masonry buildings; refer to Section 12.3.4.1 of
assemblies, and approved by the authority having
FEMA 302.
jurisdiction.
The steel deck installation for the
structures, including fasteners, should comply with
(3) Wood buildings with walls on three sides.
the test assembly arrangement.
Provide for rotation as discussed in Paragraph 7-
7b(2). Straight sheathing will not be used to resist
2. Acceptance criteria.
shears in rotation.
The depth of the diaphragm
normal to the open side will not exceed 25 feet
i. The response modification factors, R,
(7.5m), or two-thirds of the diaphragm width,
for
steel
deck
diaphragms
conforming
to
whichever is the smaller depth.
Performance Objective 1A, shall be based on the
factor for the applicable structural system in Table 7-
Exceptions:
1. The allowable shear strength shall be taken as
7 -140
Previous Page
