(c) Plywood sheathing.
(5) Acceptance criteria.
(a) The response modification factors, R,
1.
Boundary members.
All boundary
for wood diaphragms conforming to Performance
members will be proportioned and spliced where
Objectives 1A shall be based on the factor for the
necessary to transmit direct stresses. The nominal
applicable structural system in Table 7-1.
The
width of the framing members will be at least 2
nominal shear strength of wood diaphragms will be
inches (50mm). In general, panel edges will bear on
calculated by principles of mechanics using values of
the framing members and butt along their centerlines.
fastener strength and shear resistance in the sheathing
Nails will be placed not less than 3/8 inch (10mm) in
material based on approved values from cyclical
from the panel edge, not more than 12 inches
tests.
The design strength shall be the nominal
(300mm) apart along intermediate supports, and 6
strength multiplied by a resistance factor, N, equal to
inches (150mm) along panel edge bearings, and will
0.65. When approved allowable stress (including a
be firmly driven into the framing members.
No
one-third increase for wind or seismic loads), the
unblocked panels less than 12 inches (300mm) wide
design strength may be taken as 1.50 times the
will be used.
allowable values.
Factored shear capacity values
(i.e., including capacity reduction factor, N, equal to
2. Nailing. The use of pneumatically or
0.65) for plywood diaphragm are provided in Table
mechanically driven steel wire staples with a
7-25.
minimum crown width of 7/16 inch (11mm) is an
acceptable
alternative
method
of
attaching
(b) Modification factors, m, for enhanced
diaphragms.
The crown of the staple must be
performance objectives are provided in Table 7-26.
installed parallel to the framing member.
(c)
Modeling parameters and numerical
Minimum Staple
acceptance criteria for nonlinear procedures are
Penetration
Common
provided in Table 7-27.
Wire Nail
Staple
In
Framing
Member
QCE,
(d)
Expected
strength,
for
6d
14 gauge
1 inch
deformation-controlled
connections
and
other
8d
13 gauge
1 inch
elements shall be taken as the nominal strength
10d
1 1/8 inch
12 gauge
calculated in accordance with FEMA 302, without
1 inch = 25mm
the N factor.
3. Typical details. Refer to Figure 7-63.
(e)
Lower-bound strength for force-
controlled connections and other elements shall be
7 -144
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