International Building Code 2305.1
General. Structures using wood shear walls and diaphragms
to resist wind, seismic and other lateral loads shall be
designed and constructed in accordance with the provisions of
this section. Alternatively, compliance with the AF&PA
SDPWS shall be permitted subject to the limitations therein and
the limitations of this code.
Shear resistance based on principles ofmechanics.
Shear resistance of diaphragms and shear walls are permitted
to be calculated by principles of mechanics using
values of fastener strength and sheathing shear resistance.
Framing. Boundary elements shall be provided to
transmit tension and compression forces. Perimeter members
at openings shall be provided and shall be detailed to
distribute the shearing stresses. Diaphragm and shear wall
sheathing shall not be used to splice boundary elements.
Diaphragm chords and collectors shall be placed in, or tangent
to, the plane of the diaphragm framing unless it can be
demonstrated that the moments, shears and deformations,
considering eccentricities resulting from other configurations
can be tolerated without exceeding the adjusted resistance
and drift limits.
Framing members. Framing members shall
be at least 2 inch (51 mm) nominal width. In general,
adjoining panel edges shall bear and be attached to the
framing members and butt along their centerlines. Nails
shall be placed not less than 3/8 inch (9.5 mm) from the
panel edge, not more than 12 inches (305 mm) apart
along intermediate supports, and 6 inches (152 mm)
along panel edge bearings, and shall be firmly driven into
the framing members.
Openings in shear panels. Openings in shear
panels that materially affect their strength shall be fully
detailed on the plans, and shall have their edges adequately
reinforced to transfer all shearing stresses.
Shear panel connections. Positive connections
and anchorages capable of resisting the design forces shall
be provided between the shear panel and the attached components.
In Seismic Design Category D, E or F, the capacity
of toenail connections shall not be used when calculating
lateral load resistance to transfer lateral earthquake forces in
excess of 150 pounds per foot (2189 N/m) from diaphragms
to shear walls, drag struts (collectors) or other elements, or
from shear walls to other elements.
SECTION
Wood members resisting horizontal seismic
forces contributed by masonry and concrete walls.Wood
shear walls, diaphragms, horizontal trusses and other members
shall not be used to resist horizontal seismic forces contributed
by masonry or concrete walls in structures over one
story in height.
Exceptions:
1. Wood floor and roof members are permitted to be
used in horizontal trusses and diaphragms to resist
horizontal seismic forces contributed by masonry
or concrete walls, provided such forces do not
result in torsional force distribution through the
truss or diaphragm.
2. Wood structural panel sheathed shear walls are
permitted to be used to provide resistance to seismic
forces contributed by masonry or concrete
walls in two-story structures of masonry or concrete
walls, provided the following requirements
are met:
2.1. Story-to-story wall heights shall not
exceed 12 feet (3658 mm).
2.2. Diaphragms shall not be designed to transmit
lateral forces by rotation and shall not
cantilever past the outermost supporting
shear wall.
2.3. Combined deflections of diaphragms and
shear walls shall not permit story drift of
supported masonry or concrete walls to
exceed the limit of Section 12.12.1 in
ASCE 7.
2.4. Wood structural panel sheathing in diaphragms
shall have unsupported edges
blocked. Wood structural panel sheathing
for both stories of shear walls shall have
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unsupported edges blocked and, for the
lower story, shall have a minimum thickness
of 15/32 inch (11.9 mm).
2.5. There shall be no out-of-plane horizontal
offsets between the first and second stories
of wood structural panel shear walls.
Wood members resisting seismic forces from
nonstructural concrete or masonry.Wood members shall
be permitted to resist horizontal seismic forces from
nonstructural concrete, masonry veneer or concrete floors.
International Building Code 2305.1.1
Shear resistance based on principles ofmechanics.
Shear resistance of diaphragms and shear walls are permitted
to be calculated by principles of mechanics using
values of fastener strength and sheathing shear resistance.
International Building Code 2305.1.2
Framing. Boundary elements shall be provided to
transmit tension and compression forces. Perimeter members
at openings shall be provided and shall be detailed to
distribute the shearing stresses. Diaphragm and shear wall
sheathing shall not be used to splice boundary elements.
Diaphragm chords and collectors shall be placed in, or tangent
to, the plane of the diaphragm framing unless it can be
demonstrated that the moments, shears and deformations,
considering eccentricities resulting from other configurations
can be tolerated without exceeding the adjusted resistance
and drift limits.
Framing members. Framing members shall
be at least 2 inch (51 mm) nominal width. In general,
adjoining panel edges shall bear and be attached to the
framing members and butt along their centerlines. Nails
shall be placed not less than 3/8 inch (9.5 mm) from the
panel edge, not more than 12 inches (305 mm) apart
along intermediate supports, and 6 inches (152 mm)
along panel edge bearings, and shall be firmly driven into
the framing members.
International Building Code 2305.1.2.1
Framing members. Framing members shall
be at least 2 inch (51 mm) nominal width. In general,
adjoining panel edges shall bear and be attached to the
framing members and butt along their centerlines. Nails
shall be placed not less than 3/8 inch (9.5 mm) from the
panel edge, not more than 12 inches (305 mm) apart
along intermediate supports, and 6 inches (152 mm)
along panel edge bearings, and shall be firmly driven into
the framing members.
International Building Code 2305.1.3
Openings in shear panels. Openings in shear
panels that materially affect their strength shall be fully
detailed on the plans, and shall have their edges adequately
reinforced to transfer all shearing stresses.
International Building Code 2305.1.4
Shear panel connections. Positive connections
and anchorages capable of resisting the design forces shall
be provided between the shear panel and the attached components.
In Seismic Design Category D, E or F, the capacity
of toenail connections shall not be used when calculating
lateral load resistance to transfer lateral earthquake forces in
excess of 150 pounds per foot (2189 N/m) from diaphragms
to shear walls, drag struts (collectors) or other elements, or
from shear walls to other elements.
International Building Code 2305.1.5
SECTION
Wood members resisting horizontal seismic
forces contributed by masonry and concrete walls.Wood
shear walls, diaphragms, horizontal trusses and other members
shall not be used to resist horizontal seismic forces contributed
by masonry or concrete walls in structures over one
story in height.
Exceptions:
1. Wood floor and roof members are permitted to be
used in horizontal trusses and diaphragms to resist
horizontal seismic forces contributed by masonry
or concrete walls, provided such forces do not
result in torsional force distribution through the
truss or diaphragm.
2. Wood structural panel sheathed shear walls are
permitted to be used to provide resistance to seismic
forces contributed by masonry or concrete
walls in two-story structures of masonry or concrete
walls, provided the following requirements
are met:
2.1. Story-to-story wall heights shall not
exceed 12 feet (3658 mm).
2.2. Diaphragms shall not be designed to transmit
lateral forces by rotation and shall not
cantilever past the outermost supporting
shear wall.
2.3. Combined deflections of diaphragms and
shear walls shall not permit story drift of
supported masonry or concrete walls to
exceed the limit of Section 12.12.1 in
ASCE 7.
2.4. Wood structural panel sheathing in diaphragms
shall have unsupported edges
blocked. Wood structural panel sheathing
for both stories of shear walls shall have
2006 INTERNATIONAL BUILDING CODE 435
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unsupported edges blocked and, for the
lower story, shall have a minimum thickness
of 15/32 inch (11.9 mm).
2.5. There shall be no out-of-plane horizontal
offsets between the first and second stories
of wood structural panel shear walls.
International Building Code 2305.1.6
Wood members resisting seismic forces from
nonstructural concrete or masonry.Wood members shall
be permitted to resist horizontal seismic forces from
nonstructural concrete, masonry veneer or concrete floors.
International Building Code 2305.2
Design of wood diaphragms.
General. Wood diaphragms are permitted to be
used to resist horizontal forces provided the deflection in
the plane of the diaphragm, as determined by calculations,
tests or analogies drawn therefrom, does not exceed the
permissible deflection of attached distributing or resisting
elements. Connections shall extend into the diaphragm a
sufficient distance to develop the force transferred into the
diaphragm.
Deflection. Permissible deflection shall be that
deflection up to which the diaphragm and any attached distributing
or resisting element will maintain its structural
integrity under design load conditions, such that the resisting
element will continue to support design loads without
danger to occupants of the structure. Calculations for diaphragm
deflection shall account for the usual bending and
shear components as well as any other factors, such as nail
deformation, which will contribute to deflection.
The deflection ( ) of a blocked wood structural panel
diaphragm uniformly nailed throughout is permitted to be
calculated by using the following equation. If not uniformly
nailed, the constant 0.188 (For SI: 1/1627) in the third term
must be modified accordingly.
(Equation 23-1)
Diaphragm aspect ratios. Size and shape of diaphragms
shall be limited as set forth in Table 2305.2.3.
Construction. Wood diaphragms shall be constructed
of wood structural panels manufactured with exterior
glue and not less than 4 feet by 8 feet (1219mmby 2438
mm), except at boundaries and changes in framing where
minimum sheet dimension shall be 24 inches (610 mm)
unless all edges of the undersized sheets are supported by
and fastened to framing members or blocking.Wood structural
panel thickness for horizontal diaphragms shall not be
less than the valves set forth in Tables 2304.7(3), 2304.7(4)
and 2304.7(5) for corresponding joist spacing and loads.
436 2006 INTERNATIONAL BUILDING CODE
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Seismic Design Category F. Structures
assigned to Seismic Design Category F shall conform to
the additional requirements of this section.
Wood structural panel sheathing used for diaphragms
and shear walls that are part of the seismic-force-resisting
system shall be applied directly to the framing members.
Exception:Wood structural panel sheathing in a diaphragm
is permitted to be fastened over solid lumber
planking or laminated decking, provided the panel
joints and lumber planking or laminated decking
joints do not coincide.
Rigid diaphragms. Design of structures with
rigid diaphragms shall conform to the structure configuration
requirements of Section 12.3.2 of ASCE 7 and the horizontal
shear distribution requirements of Section 12.8.4 of
ASCE 7.
Open-front structures with rigidwood diaphragms resulting
in torsional force distribution are permitted, provided
the length, l, of the diaphragm normal to the open side does
not exceed 25 feet (7620 mm), the diaphragm sheathing
conforms to Section 2305.2.4 and the l/w ratio [as shown in
Figure 2305.2.5(1)] is less than 1 for one-story structures or
0.67 for structures over one story in height.
Exception: Where calculations show that diaphragm
deflections can be tolerated, the length, l, normal to the
open end is permitted to be increased to a l/w ratio not
greater than 1.5 where sheathed in compliance with Section
2305.2.4 or to 1 where sheathed in compliance with
Section 2306.3.4 or 2306.3.5.
Rigid wood diaphragms are permitted to cantilever past
the outermost supporting shearwall (or other vertical resisting
element) a length, l, of not more than 25 feet (7620 mm)
or two-thirds of the diaphragm width, w, whichever is
smaller. Figure 2305.2.5(2) illustrates the dimensions of l
and w for a cantilevered diaphragm.
Structures with rigidwood diaphragms having a torsional
irregularity in accordance with Table 12.3-1, Item 1, of
ASCE 7 shall meet the following requirements: the l/w ratio
shall not exceed 1 for one-story structures or 0.67 for
structures over one story in height, where l is the dimension
parallel to the load direction for which the irregularity
exists.
Exception: Where calculations demonstrate that the diaphragm
deflections can be tolerated, the width is permitted
to be increased and the l/w ratio is permitted to be
increased to 1.5 where sheathed in compliance with Section
2305.2.4 or 1 where sheathed in compliance with
Section 2306.3.4 or 2306.3.5.
International Building Code 2305.2.1
General. Wood diaphragms are permitted to be
used to resist horizontal forces provided the deflection in
the plane of the diaphragm, as determined by calculations,
tests or analogies drawn therefrom, does not exceed the
permissible deflection of attached distributing or resisting
elements. Connections shall extend into the diaphragm a
sufficient distance to develop the force transferred into the
diaphragm.
International Building Code 2305.2.2
Deflection. Permissible deflection shall be that
deflection up to which the diaphragm and any attached distributing
or resisting element will maintain its structural
integrity under design load conditions, such that the resisting
element will continue to support design loads without
danger to occupants of the structure. Calculations for diaphragm
deflection shall account for the usual bending and
shear components as well as any other factors, such as nail
deformation, which will contribute to deflection.
The deflection ( ) of a blocked wood structural panel
diaphragm uniformly nailed throughout is permitted to be
calculated by using the following equation. If not uniformly
nailed, the constant 0.188 (For SI: 1/1627) in the third term
must be modified accordingly.
(Equation 23-1)
International Building Code 2305.2.3
Diaphragm aspect ratios. Size and shape of diaphragms
shall be limited as set forth in Table 2305.2.3.
International Building Code 2305.2.4
Construction. Wood diaphragms shall be constructed
of wood structural panels manufactured with exterior
glue and not less than 4 feet by 8 feet (1219mmby 2438
mm), except at boundaries and changes in framing where
minimum sheet dimension shall be 24 inches (610 mm)
unless all edges of the undersized sheets are supported by
and fastened to framing members or blocking.Wood structural
panel thickness for horizontal diaphragms shall not be
less than the valves set forth in Tables 2304.7(3), 2304.7(4)
and 2304.7(5) for corresponding joist spacing and loads.
436 2006 INTERNATIONAL BUILDING CODE
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Seismic Design Category F. Structures
assigned to Seismic Design Category F shall conform to
the additional requirements of this section.
Wood structural panel sheathing used for diaphragms
and shear walls that are part of the seismic-force-resisting
system shall be applied directly to the framing members.
Exception:Wood structural panel sheathing in a diaphragm
is permitted to be fastened over solid lumber
planking or laminated decking, provided the panel
joints and lumber planking or laminated decking
joints do not coincide.
International Building Code 2305.2.4.1
Seismic Design Category F. Structures
assigned to Seismic Design Category F shall conform to
the additional requirements of this section.
Wood structural panel sheathing used for diaphragms
and shear walls that are part of the seismic-force-resisting
system shall be applied directly to the framing members.
Exception:Wood structural panel sheathing in a diaphragm
is permitted to be fastened over solid lumber
planking or laminated decking, provided the panel
joints and lumber planking or laminated decking
joints do not coincide.
International Building Code 2305.2.5
Rigid diaphragms. Design of structures with
rigid diaphragms shall conform to the structure configuration
requirements of Section 12.3.2 of ASCE 7 and the horizontal
shear distribution requirements of Section 12.8.4 of
ASCE 7.
Open-front structures with rigidwood diaphragms resulting
in torsional force distribution are permitted, provided
the length, l, of the diaphragm normal to the open side does
not exceed 25 feet (7620 mm), the diaphragm sheathing
conforms to Section 2305.2.4 and the l/w ratio [as shown in
Figure 2305.2.5(1)] is less than 1 for one-story structures or
0.67 for structures over one story in height.
Exception: Where calculations show that diaphragm
deflections can be tolerated, the length, l, normal to the
open end is permitted to be increased to a l/w ratio not
greater than 1.5 where sheathed in compliance with Section
2305.2.4 or to 1 where sheathed in compliance with
Section 2306.3.4 or 2306.3.5.
Rigid wood diaphragms are permitted to cantilever past
the outermost supporting shearwall (or other vertical resisting
element) a length, l, of not more than 25 feet (7620 mm)
or two-thirds of the diaphragm width, w, whichever is
smaller. Figure 2305.2.5(2) illustrates the dimensions of l
and w for a cantilevered diaphragm.
Structures with rigidwood diaphragms having a torsional
irregularity in accordance with Table 12.3-1, Item 1, of
ASCE 7 shall meet the following requirements: the l/w ratio
shall not exceed 1 for one-story structures or 0.67 for
structures over one story in height, where l is the dimension
parallel to the load direction for which the irregularity
exists.
Exception: Where calculations demonstrate that the diaphragm
deflections can be tolerated, the width is permitted
to be increased and the l/w ratio is permitted to be
increased to 1.5 where sheathed in compliance with Section
2305.2.4 or 1 where sheathed in compliance with
Section 2306.3.4 or 2306.3.5.
International Building Code 2305.3
Design of wood shear walls.
General.Wood shear walls are permitted to resist
horizontal forces in vertical distributing or resisting elements,
provided the deflection in the plane of the shearwall,
as determined by calculations, tests or analogies drawn
therefrom, does not exceed the more restrictive of the permissible
deflection of attached distributing or resisting elements
or the drift limits of Section 12.12.1 ofASCE7. Shear
wall sheathing other thanwood structural panels shall not be
permitted in Seismic Design Category E or F (see Section
1613).
Deflection. Permissible deflection shall be that
deflection up to which the shear wall and any attached distributing
or resisting element will maintain its structural
integrity under design load conditions, i.e., continue to support
design loads without danger to occupants of the structure.
The deflection (?) of a blocked wood structural panel
shear wall uniformly fastened throughout is permitted to be
calculated by the use of the following equation:
(Equation 23-2)
Construction. Wood shear walls shall be constructed
of wood structural panels manufactured with exterior
glue and not less than 4 feet by 8 feet (1219mmby 2438
mm), except at boundaries and at changes in framing. All
edges of all panels shall be supported by and fastened to
framing members or blocking.Wood structural panel thickness
for shear walls shall not be less than set forth in Table
2304.6.1 for corresponding framing spacing and loads,
except that 1/4 inch (6.4 mm) is permitted to be used where
perpendicular loads permit.
Shear wall aspect ratios. Size and shape of shear
walls, perforated shear wall segments within perforated
shear walls and wall piers within shear walls that are
designed for force transfer around openings shall be limited
as set forth in Table 2305.3.4. The height, h, and the width,
w, shall be determined in accordance with Sections 2305.3.5
through 2305.3.5.2 and 2305.3.6 through 2305.3.6.2,
respectively.
Shear wall height definition. The height of a
shear wall, h, shall be defined as:
1. The maximum clear height from the top of the foundation
to the bottom of the diaphragm framing above;
or
2. The maximum clear height from the top of the diaphragm
to the bottom of the diaphragm framing
above [see Figure 2305.3.5(a)].
Perforated shear wall segment height definition.
The height of a perforated shear wall segment, h,
shall be defined as specified in Section 2305.3.5 for shear
walls.
Force transfer shear wall pier height definition.
The height, h, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the clear height of the pier at the side
of an opening [see Figure 2305.3.5(b)].
Shear wall width definition. The width of a shear
wall, w, shall be defined as the sheathed dimension of the
shearwall in the direction of application of force [see Figure
2305.3.5(a)].
2006 INTERNATIONAL BUILDING CODE 439
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FIGURE 2305.2.5(2)
DIAPHRAGM LENGTH AND WIDTH FOR PLAN VIEW OF CANTILEVERED DIAPHRAGM
?
Perforated shear wall segment width definition.
The width of a perforated shear wall segment, w,
shall be defined as the width of full-height sheathing
adjacent to openings in the perforated shear wall [see
Figure 2305.3.5(a)].
Force transfer shear wall pier width definition.
The width, w, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the sheathed width of the pier at the
side of an opening [see Figure 2305.3.5(b)].
Overturning restraint. Where the dead load stabilizing
moment in accordance with Chapter 16 allowable
stress design load combinations is not sufficient to prevent
uplift due to overturning moments on thewall, an anchoring
device shall be provided. Anchoring devices shall maintain
a continuous load path to the foundation.
Shear walls with openings. The provisions of this
section shall apply to the design of shear walls with openings.
Where framing and connections around the openings
are designed for force transfer around the openings, the provisions
of Section 2305.3.8.1 shall apply. Where framing
and connections around the openings are not designed for
force transfer around the openings, the provisions of Section
2305.3.8.2 shall apply.
Force transfer around openings. Where
shear walls with openings are designed for force transfer
around the openings, the limitations of Table 2305.3.4
shall apply to the overall shear wall, including openings,
and to eachwall pier at the side of an opening. Design for
force transfer shall be based on a rational analysis.
Detailing of boundary elements around the opening shall
be provided in accordance with the provisions of this section[
see Figure 2305.3.5(b)].
Perforated shear walls. The provisions of
Section 2305.3.8.2 shall be permitted to be used for the
design of perforated shear walls. For the determination
of the height and width of perforated shear wall segments,
see Sections 2305.3.5.1 and 2305.3.6.1, respectively.
Limitations. The following limitations
shall apply to the use of Section 2305.3.8.2:
1. A perforated shear wall segment shall be
located at each end of a perforated shear wall.
Openings shall be permitted to occur beyond
the ends of the perforated shear wall, provided
the width of such openings is not be included in
the width of the perforated shear wall.
2. The allowable shear set forth in Table 2306.4.1
shall not exceed 490 plf (7150 N/m).
3. Where out-of-plane offsets occur, portions of
the wall on each side of the offset shall be considered
as separate perforated shear walls.
4. Collectors for shear transfer shall be provided
through the full length of the perforated shear
wall.
5. A perforated shear wall shall have uniform top
of wall and bottom of wall elevations. Perfo-
440 2006 INTERNATIONAL BUILDING CODE
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FIGURE 2305.3.5
GENERAL DEFINITION OF SHEAR WALL HEIGHT, WIDTH AND HEIGHT-TO-WIDTH RATIO
rated shear walls not having uniform elevations
shall be designed by other methods.
6. Perforated shear wall height, h, shall not exceed
20 feet (6096 mm).
Perforated shear wall resistance. The
resistance of a perforated shear wall shall be calculated
in accordance with the following:
1. The percentage of full-height sheathing shall be
calculated as the sum of the widths of perforated
shearwall segments divided by the totalwidth of
the perforated shear wall, including openings.
2. The maximum opening height shall be taken as
the maximum opening clear height. Where
areas above and below an opening remain
unsheathed, the height of the opening shall be
defined as the height of the wall.
3. The unadjusted shear resistance shall be the
allowable shear set forth in Table 2306.4.1 for
height-to-width ratios of perforated shear wall
segments that do not exceed 2:1 for seismic
forces and 31/2:1 for other than seismic forces.
For seismic forces, where the height-to-width
ratio of any perforated shear wall segment used
in the calculation of the sum of the widths of
perforated shear wall segments, _ Li, is greater
than 2:1 but does not exceed 31/2:1, the unadjusted
shear resistance shall be multiplied by 2
w/h.
4. The adjusted shear resistance shall be calculated
by multiplying the unadjusted shear resistance
by the shear resistance adjustment factors
of Table 2305.3.8.2. For intermediate percentages
of full-height sheathing, the values in
Table 2305.3.8.2 are permitted to be interpolated.
5. The perforated shear wall resistance shall be
equal to the adjusted shear resistance times the
sum of the widths of the perforated shear wall
segments.
Anchorage and load path. Design of
perforated shear wall anchorage and load path shall
conform to the requirements of Sections 2305.3.8.2.4
through 2305.3.8.2.8, or shall be calculated using
principles of mechanics. Except as modified by these
sections, wall framing, sheathing, sheathing attachment
and fastener schedules shall conform to the
requirements of Section 2305.2.4 and Table 2306.4.1.
Uplift anchorage at perforated shear
wall ends. Anchorage for uplift forces due to overturning
shall be provided at each end of the perforated
shear wall. The uplift anchorage shall conform to the
requirements of Section 2305.3.7, except that for each
story the minimum tension chord uplift force, T, shall
be calculated in accordance with the following:
(Equation 23-3)
Anchorage for in-plane shear. The unit
shear force, v, transmitted into the top of a perforated
shear wall, out of the base of the perforated shear wall
at full height sheathing and into collectors connecting
shear wall segments shall be calculated in accordance
with the following:
(Equation 23-4)
Uplift anchorage between perforated
shear wall ends. In addition to the requirements of
Section 2305.3.8.2.4, perforated shear wall bottom
plates at full-height sheathing shall be anchored for a
uniform uplift force, t, equal to the unit shear force, v,
determined in Section 2305.3.8.2.5.
Compression chords. Each end of each
perforated shear wall segment shall be designed for a
compression chord force, C, equal to the tension
chord uplift force, T, calculated in Section
2305.3.8.2.4.
Load path. Load path. A load path to
the foundation shall be provided for each uplift force,
T and t, for each shear force, V and v, and for each
compression chord force, C. Elements resisting shear
wall forces contributed by multiple stories shall be
designed for the sum of forces contributed by each
story.
Deflection of shear walls with openings.
The controlling deflection of a blocked shear
wall with openings uniformly fastened throughout
shall be taken as the maximum individual deflection
of the shear wall segments calculated in accordance
with Section 2305.3.2, divided by the appropriate
shear resistance adjustment factors of Table
2305.3.8.2.
Summing shear capacities. The shear values for
shear panels of different capacities applied to the same side
of the wall are not cumulative except as allowed in Table
2306.4.1.
The shear values for material of the same type and
capacity applied to both faces of the samewall are cumulative.
Where thematerial capacities are not equal, the allowable
shear shall be either two times the smaller shear
capacity or the capacity of the stronger side, whichever is
greater.
Summing shear capacities of dissimilar materials
applied to opposite faces or to the same wall line is not
allowed.
Exception: Forwind design, the allowable shear capacity
of shear wall segments sheathed with a combination
of wood structural panels and gypsum wallboard on
opposite faces, fiberboard structural sheathing and gypsum
wallboard on opposite faces or hardboard panel
siding and gypsum wallboard on opposite faces shall
equal the sum of the sheathing capacities of each face
separately.
Adhesives. Adhesive attachment of shear wall
sheathing is not permitted as a substitute for mechanical
fasteners, and shall not be used in shear wall strength calculations
alone, or in combination with mechanical fasteners
in Seismic Design Category D, E or F.
Sill plate size and anchorage in Seismic Design
Category D, E or F. Anchor bolts for shear walls shall
include steel plate washers, a minimum of 0.229 inch by 3
inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size,
between the sill plate and nut. The hole in the platewasher is
permitted to be diagonally slotted with a width of up to 3/16
inch (4.76 mm) larger than the bolt diameter and a slot
length not to exceed 13/4 inches (44 mm), provided a standard
cut washer is placed between the plate washer and the
nut. Sill plates resisting a design load greater than 490 plf
(7154 N/m) using load and resistance factor design or 350
plf (5110 N/m) using allowable stress design shall not be
less than a 3-inch (76 mm) nominal member. Where a single
3- inch (76 mm) nominal sill plate is used, 2- 20d box end
nails shall be substituted for 2-16d common end nails found
in line 8 of Table 2304.9.1.
Exception: In shear walls where the design load is
greater than 490 plf (7151 N/m) but less than 840 plf (12
264 N/m) using load and resistance factor design or
greater than 350 plf (5110 N/m) but less than 600 plf
(8760 N/m) using allowable stress design, the sill plate is
permitted to be a 2-inch (51 mm) nominal member if the
sill plate is anchored by two times the number of bolts
required by design and 0.229-inch by 3-inch by 3-inch
(5.82mmby 76mmby 76mm)platewashers are used.
International Building Code 2305.3.1
General.Wood shear walls are permitted to resist
horizontal forces in vertical distributing or resisting elements,
provided the deflection in the plane of the shearwall,
as determined by calculations, tests or analogies drawn
therefrom, does not exceed the more restrictive of the permissible
deflection of attached distributing or resisting elements
or the drift limits of Section 12.12.1 ofASCE7. Shear
wall sheathing other thanwood structural panels shall not be
permitted in Seismic Design Category E or F (see Section
1613).
International Building Code 2305.3.10
Adhesives. Adhesive attachment of shear wall
sheathing is not permitted as a substitute for mechanical
fasteners, and shall not be used in shear wall strength calculations
alone, or in combination with mechanical fasteners
in Seismic Design Category D, E or F.
International Building Code 2305.3.11
Sill plate size and anchorage in Seismic Design
Category D, E or F. Anchor bolts for shear walls shall
include steel plate washers, a minimum of 0.229 inch by 3
inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size,
between the sill plate and nut. The hole in the platewasher is
permitted to be diagonally slotted with a width of up to 3/16
inch (4.76 mm) larger than the bolt diameter and a slot
length not to exceed 13/4 inches (44 mm), provided a standard
cut washer is placed between the plate washer and the
nut. Sill plates resisting a design load greater than 490 plf
(7154 N/m) using load and resistance factor design or 350
plf (5110 N/m) using allowable stress design shall not be
less than a 3-inch (76 mm) nominal member. Where a single
3- inch (76 mm) nominal sill plate is used, 2- 20d box end
nails shall be substituted for 2-16d common end nails found
in line 8 of Table 2304.9.1.
Exception: In shear walls where the design load is
greater than 490 plf (7151 N/m) but less than 840 plf (12
264 N/m) using load and resistance factor design or
greater than 350 plf (5110 N/m) but less than 600 plf
(8760 N/m) using allowable stress design, the sill plate is
permitted to be a 2-inch (51 mm) nominal member if the
sill plate is anchored by two times the number of bolts
required by design and 0.229-inch by 3-inch by 3-inch
(5.82mmby 76mmby 76mm)platewashers are used.
International Building Code 2305.3.2
Deflection. Permissible deflection shall be that
deflection up to which the shear wall and any attached distributing
or resisting element will maintain its structural
integrity under design load conditions, i.e., continue to support
design loads without danger to occupants of the structure.
The deflection (?) of a blocked wood structural panel
shear wall uniformly fastened throughout is permitted to be
calculated by the use of the following equation:
(Equation 23-2)
International Building Code 2305.3.3
Construction. Wood shear walls shall be constructed
of wood structural panels manufactured with exterior
glue and not less than 4 feet by 8 feet (1219mmby 2438
mm), except at boundaries and at changes in framing. All
edges of all panels shall be supported by and fastened to
framing members or blocking.Wood structural panel thickness
for shear walls shall not be less than set forth in Table
2304.6.1 for corresponding framing spacing and loads,
except that 1/4 inch (6.4 mm) is permitted to be used where
perpendicular loads permit.
International Building Code 2305.3.4
Shear wall aspect ratios. Size and shape of shear
walls, perforated shear wall segments within perforated
shear walls and wall piers within shear walls that are
designed for force transfer around openings shall be limited
as set forth in Table 2305.3.4. The height, h, and the width,
w, shall be determined in accordance with Sections 2305.3.5
through 2305.3.5.2 and 2305.3.6 through 2305.3.6.2,
respectively.
International Building Code 2305.3.5
Shear wall height definition. The height of a
shear wall, h, shall be defined as:
1. The maximum clear height from the top of the foundation
to the bottom of the diaphragm framing above;
or
2. The maximum clear height from the top of the diaphragm
to the bottom of the diaphragm framing
above [see Figure 2305.3.5(a)].
Perforated shear wall segment height definition.
The height of a perforated shear wall segment, h,
shall be defined as specified in Section 2305.3.5 for shear
walls.
Force transfer shear wall pier height definition.
The height, h, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the clear height of the pier at the side
of an opening [see Figure 2305.3.5(b)].
International Building Code 2305.3.5.1
Perforated shear wall segment height definition.
The height of a perforated shear wall segment, h,
shall be defined as specified in Section 2305.3.5 for shear
walls.
International Building Code 2305.3.5.2
Force transfer shear wall pier height definition.
The height, h, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the clear height of the pier at the side
of an opening [see Figure 2305.3.5(b)].
International Building Code 2305.3.6
Shear wall width definition. The width of a shear
wall, w, shall be defined as the sheathed dimension of the
shearwall in the direction of application of force [see Figure
2305.3.5(a)].
2006 INTERNATIONAL BUILDING CODE 439
WOOD
FIGURE 2305.2.5(2)
DIAPHRAGM LENGTH AND WIDTH FOR PLAN VIEW OF CANTILEVERED DIAPHRAGM
?
Perforated shear wall segment width definition.
The width of a perforated shear wall segment, w,
shall be defined as the width of full-height sheathing
adjacent to openings in the perforated shear wall [see
Figure 2305.3.5(a)].
Force transfer shear wall pier width definition.
The width, w, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the sheathed width of the pier at the
side of an opening [see Figure 2305.3.5(b)].
International Building Code 2305.3.6.1
Perforated shear wall segment width definition.
The width of a perforated shear wall segment, w,
shall be defined as the width of full-height sheathing
adjacent to openings in the perforated shear wall [see
Figure 2305.3.5(a)].
International Building Code 2305.3.6.2
Force transfer shear wall pier width definition.
The width, w, of a wall pier in a shear wall with
openings designed for force transfer around openings
shall be defined as the sheathed width of the pier at the
side of an opening [see Figure 2305.3.5(b)].
International Building Code 2305.3.7
Overturning restraint. Where the dead load stabilizing
moment in accordance with Chapter 16 allowable
stress design load combinations is not sufficient to prevent
uplift due to overturning moments on thewall, an anchoring
device shall be provided. Anchoring devices shall maintain
a continuous load path to the foundation.
International Building Code 2305.3.8
Shear walls with openings. The provisions of this
section shall apply to the design of shear walls with openings.
Where framing and connections around the openings
are designed for force transfer around the openings, the provisions
of Section 2305.3.8.1 shall apply. Where framing
and connections around the openings are not designed for
force transfer around the openings, the provisions of Section
2305.3.8.2 shall apply.
Force transfer around openings. Where
shear walls with openings are designed for force transfer
around the openings, the limitations of Table 2305.3.4
shall apply to the overall shear wall, including openings,
and to eachwall pier at the side of an opening. Design for
force transfer shall be based on a rational analysis.
Detailing of boundary elements around the opening shall
be provided in accordance with the provisions of this section[
see Figure 2305.3.5(b)].
Perforated shear walls. The provisions of
Section 2305.3.8.2 shall be permitted to be used for the
design of perforated shear walls. For the determination
of the height and width of perforated shear wall segments,
see Sections 2305.3.5.1 and 2305.3.6.1, respectively.
Limitations. The following limitations
shall apply to the use of Section 2305.3.8.2:
1. A perforated shear wall segment shall be
located at each end of a perforated shear wall.
Openings shall be permitted to occur beyond
the ends of the perforated shear wall, provided
the width of such openings is not be included in
the width of the perforated shear wall.
2. The allowable shear set forth in Table 2306.4.1
shall not exceed 490 plf (7150 N/m).
3. Where out-of-plane offsets occur, portions of
the wall on each side of the offset shall be considered
as separate perforated shear walls.
4. Collectors for shear transfer shall be provided
through the full length of the perforated shear
wall.
5. A perforated shear wall shall have uniform top
of wall and bottom of wall elevations. Perfo-
440 2006 INTERNATIONAL BUILDING CODE
WOOD
FIGURE 2305.3.5
GENERAL DEFINITION OF SHEAR WALL HEIGHT, WIDTH AND HEIGHT-TO-WIDTH RATIO
rated shear walls not having uniform elevations
shall be designed by other methods.
6. Perforated shear wall height, h, shall not exceed
20 feet (6096 mm).
Perforated shear wall resistance. The
resistance of a perforated shear wall shall be calculated
in accordance with the following:
1. The percentage of full-height sheathing shall be
calculated as the sum of the widths of perforated
shearwall segments divided by the totalwidth of
the perforated shear wall, including openings.
2. The maximum opening height shall be taken as
the maximum opening clear height. Where
areas above and below an opening remain
unsheathed, the height of the opening shall be
defined as the height of the wall.
3. The unadjusted shear resistance shall be the
allowable shear set forth in Table 2306.4.1 for
height-to-width ratios of perforated shear wall
segments that do not exceed 2:1 for seismic
forces and 31/2:1 for other than seismic forces.
For seismic forces, where the height-to-width
ratio of any perforated shear wall segment used
in the calculation of the sum of the widths of
perforated shear wall segments, _ Li, is greater
than 2:1 but does not exceed 31/2:1, the unadjusted
shear resistance shall be multiplied by 2
w/h.
4. The adjusted shear resistance shall be calculated
by multiplying the unadjusted shear resistance
by the shear resistance adjustment factors
of Table 2305.3.8.2. For intermediate percentages
of full-height sheathing, the values in
Table 2305.3.8.2 are permitted to be interpolated.
5. The perforated shear wall resistance shall be
equal to the adjusted shear resistance times the
sum of the widths of the perforated shear wall
segments.
Anchorage and load path. Design of
perforated shear wall anchorage and load path shall
conform to the requirements of Sections 2305.3.8.2.4
through 2305.3.8.2.8, or shall be calculated using
principles of mechanics. Except as modified by these
sections, wall framing, sheathing, sheathing attachment
and fastener schedules shall conform to the
requirements of Section 2305.2.4 and Table 2306.4.1.
Uplift anchorage at perforated shear
wall ends. Anchorage for uplift forces due to overturning
shall be provided at each end of the perforated
shear wall. The uplift anchorage shall conform to the
requirements of Section 2305.3.7, except that for each
story the minimum tension chord uplift force, T, shall
be calculated in accordance with the following:
(Equation 23-3)
Anchorage for in-plane shear. The unit
shear force, v, transmitted into the top of a perforated
shear wall, out of the base of the perforated shear wall
at full height sheathing and into collectors connecting
shear wall segments shall be calculated in accordance
with the following:
(Equation 23-4)
Uplift anchorage between perforated
shear wall ends. In addition to the requirements of
Section 2305.3.8.2.4, perforated shear wall bottom
plates at full-height sheathing shall be anchored for a
uniform uplift force, t, equal to the unit shear force, v,
determined in Section 2305.3.8.2.5.
Compression chords. Each end of each
perforated shear wall segment shall be designed for a
compression chord force, C, equal to the tension
chord uplift force, T, calculated in Section
2305.3.8.2.4.
Load path. Load path. A load path to
the foundation shall be provided for each uplift force,
T and t, for each shear force, V and v, and for each
compression chord force, C. Elements resisting shear
wall forces contributed by multiple stories shall be
designed for the sum of forces contributed by each
story.
Deflection of shear walls with openings.
The controlling deflection of a blocked shear
wall with openings uniformly fastened throughout
shall be taken as the maximum individual deflection
of the shear wall segments calculated in accordance
with Section 2305.3.2, divided by the appropriate
shear resistance adjustment factors of Table
2305.3.8.2.
International Building Code 2305.3.8.1
Force transfer around openings. Where
shear walls with openings are designed for force transfer
around the openings, the limitations of Table 2305.3.4
shall apply to the overall shear wall, including openings,
and to eachwall pier at the side of an opening. Design for
force transfer shall be based on a rational analysis.
Detailing of boundary elements around the opening shall
be provided in accordance with the provisions of this section[
see Figure 2305.3.5(b)].
International Building Code 2305.3.8.2
Perforated shear walls. The provisions of
Section 2305.3.8.2 shall be permitted to be used for the
design of perforated shear walls. For the determination
of the height and width of perforated shear wall segments,
see Sections 2305.3.5.1 and 2305.3.6.1, respectively.
Limitations. The following limitations
shall apply to the use of Section 2305.3.8.2:
1. A perforated shear wall segment shall be
located at each end of a perforated shear wall.
Openings shall be permitted to occur beyond
the ends of the perforated shear wall, provided
the width of such openings is not be included in
the width of the perforated shear wall.
2. The allowable shear set forth in Table 2306.4.1
shall not exceed 490 plf (7150 N/m).
3. Where out-of-plane offsets occur, portions of
the wall on each side of the offset shall be considered
as separate perforated shear walls.
4. Collectors for shear transfer shall be provided
through the full length of the perforated shear
wall.
5. A perforated shear wall shall have uniform top
of wall and bottom of wall elevations. Perfo-
440 2006 INTERNATIONAL BUILDING CODE
WOOD
FIGURE 2305.3.5
GENERAL DEFINITION OF SHEAR WALL HEIGHT, WIDTH AND HEIGHT-TO-WIDTH RATIO
rated shear walls not having uniform elevations
shall be designed by other methods.
6. Perforated shear wall height, h, shall not exceed
20 feet (6096 mm).
Perforated shear wall resistance. The
resistance of a perforated shear wall shall be calculated
in accordance with the following:
1. The percentage of full-height sheathing shall be
calculated as the sum of the widths of perforated
shearwall segments divided by the totalwidth of
the perforated shear wall, including openings.
2. The maximum opening height shall be taken as
the maximum opening clear height. Where
areas above and below an opening remain
unsheathed, the height of the opening shall be
defined as the height of the wall.
3. The unadjusted shear resistance shall be the
allowable shear set forth in Table 2306.4.1 for
height-to-width ratios of perforated shear wall
segments that do not exceed 2:1 for seismic
forces and 31/2:1 for other than seismic forces.
For seismic forces, where the height-to-width
ratio of any perforated shear wall segment used
in the calculation of the sum of the widths of
perforated shear wall segments, _ Li, is greater
than 2:1 but does not exceed 31/2:1, the unadjusted
shear resistance shall be multiplied by 2
w/h.
4. The adjusted shear resistance shall be calculated
by multiplying the unadjusted shear resistance
by the shear resistance adjustment factors
of Table 2305.3.8.2. For intermediate percentages
of full-height sheathing, the values in
Table 2305.3.8.2 are permitted to be interpolated.
5. The perforated shear wall resistance shall be
equal to the adjusted shear resistance times the
sum of the widths of the perforated shear wall
segments.
Anchorage and load path. Design of
perforated shear wall anchorage and load path shall
conform to the requirements of Sections 2305.3.8.2.4
through 2305.3.8.2.8, or shall be calculated using
principles of mechanics. Except as modified by these
sections, wall framing, sheathing, sheathing attachment
and fastener schedules shall conform to the
requirements of Section 2305.2.4 and Table 2306.4.1.
Uplift anchorage at perforated shear
wall ends. Anchorage for uplift forces due to overturning
shall be provided at each end of the perforated
shear wall. The uplift anchorage shall conform to the
requirements of Section 2305.3.7, except that for each
story the minimum tension chord uplift force, T, shall
be calculated in accordance with the following:
(Equation 23-3)
Anchorage for in-plane shear. The unit
shear force, v, transmitted into the top of a perforated
shear wall, out of the base of the perforated shear wall
at full height sheathing and into collectors connecting
shear wall segments shall be calculated in accordance
with the following:
(Equation 23-4)
Uplift anchorage between perforated
shear wall ends. In addition to the requirements of
Section 2305.3.8.2.4, perforated shear wall bottom
plates at full-height sheathing shall be anchored for a
uniform uplift force, t, equal to the unit shear force, v,
determined in Section 2305.3.8.2.5.
Compression chords. Each end of each
perforated shear wall segment shall be designed for a
compression chord force, C, equal to the tension
chord uplift force, T, calculated in Section
2305.3.8.2.4.
Load path. Load path. A load path to
the foundation shall be provided for each uplift force,
T and t, for each shear force, V and v, and for each
compression chord force, C. Elements resisting shear
wall forces contributed by multiple stories shall be
designed for the sum of forces contributed by each
story.
Deflection of shear walls with openings.
The controlling deflection of a blocked shear
wall with openings uniformly fastened throughout
shall be taken as the maximum individual deflection
of the shear wall segments calculated in accordance
with Section 2305.3.2, divided by the appropriate
shear resistance adjustment factors of Table
2305.3.8.2.
International Building Code 2305.3.8.2.1
Limitations. The following limitations
shall apply to the use of Section 2305.3.8.2:
1. A perforated shear wall segment shall be
located at each end of a perforated shear wall.
Openings shall be permitted to occur beyond
the ends of the perforated shear wall, provided
the width of such openings is not be included in
the width of the perforated shear wall.
2. The allowable shear set forth in Table 2306.4.1
shall not exceed 490 plf (7150 N/m).
3. Where out-of-plane offsets occur, portions of
the wall on each side of the offset shall be considered
as separate perforated shear walls.
4. Collectors for shear transfer shall be provided
through the full length of the perforated shear
wall.
5. A perforated shear wall shall have uniform top
of wall and bottom of wall elevations. Perfo-
440 2006 INTERNATIONAL BUILDING CODE
WOOD
FIGURE 2305.3.5
GENERAL DEFINITION OF SHEAR WALL HEIGHT, WIDTH AND HEIGHT-TO-WIDTH RATIO
rated shear walls not having uniform elevations
shall be designed by other methods.
6. Perforated shear wall height, h, shall not exceed
20 feet (6096 mm).
International Building Code 2305.3.8.2.2
Perforated shear wall resistance. The
resistance of a perforated shear wall shall be calculated
in accordance with the following:
1. The percentage of full-height sheathing shall be
calculated as the sum of the widths of perforated
shearwall segments divided by the totalwidth of
the perforated shear wall, including openings.
2. The maximum opening height shall be taken as
the maximum opening clear height. Where
areas above and below an opening remain
unsheathed, the height of the opening shall be
defined as the height of the wall.
3. The unadjusted shear resistance shall be the
allowable shear set forth in Table 2306.4.1 for
height-to-width ratios of perforated shear wall
segments that do not exceed 2:1 for seismic
forces and 31/2:1 for other than seismic forces.
For seismic forces, where the height-to-width
ratio of any perforated shear wall segment used
in the calculation of the sum of the widths of
perforated shear wall segments, _ Li, is greater
than 2:1 but does not exceed 31/2:1, the unadjusted
shear resistance shall be multiplied by 2
w/h.
4. The adjusted shear resistance shall be calculated
by multiplying the unadjusted shear resistance
by the shear resistance adjustment factors
of Table 2305.3.8.2. For intermediate percentages
of full-height sheathing, the values in
Table 2305.3.8.2 are permitted to be interpolated.
5. The perforated shear wall resistance shall be
equal to the adjusted shear resistance times the
sum of the widths of the perforated shear wall
segments.
International Building Code 2305.3.8.2.3
Anchorage and load path. Design of
perforated shear wall anchorage and load path shall
conform to the requirements of Sections 2305.3.8.2.4
through 2305.3.8.2.8, or shall be calculated using
principles of mechanics. Except as modified by these
sections, wall framing, sheathing, sheathing attachment
and fastener schedules shall conform to the
requirements of Section 2305.2.4 and Table 2306.4.1.
International Building Code 2305.3.8.2.4
Uplift anchorage at perforated shear
wall ends. Anchorage for uplift forces due to overturning
shall be provided at each end of the perforated
shear wall. The uplift anchorage shall conform to the
requirements of Section 2305.3.7, except that for each
story the minimum tension chord uplift force, T, shall
be calculated in accordance with the following:
(Equation 23-3)
International Building Code 2305.3.8.2.5
Anchorage for in-plane shear. The unit
shear force, v, transmitted into the top of a perforated
shear wall, out of the base of the perforated shear wall
at full height sheathing and into collectors connecting
shear wall segments shall be calculated in accordance
with the following:
(Equation 23-4)
International Building Code 2305.3.8.2.6
Uplift anchorage between perforated
shear wall ends. In addition to the requirements of
Section 2305.3.8.2.4, perforated shear wall bottom
plates at full-height sheathing shall be anchored for a
uniform uplift force, t, equal to the unit shear force, v,
determined in Section 2305.3.8.2.5.
International Building Code 2305.3.8.2.7
Compression chords. Each end of each
perforated shear wall segment shall be designed for a
compression chord force, C, equal to the tension
chord uplift force, T, calculated in Section
2305.3.8.2.4.
International Building Code 2305.3.8.2.8
Load path. Load path. A load path to
the foundation shall be provided for each uplift force,
T and t, for each shear force, V and v, and for each
compression chord force, C. Elements resisting shear
wall forces contributed by multiple stories shall be
designed for the sum of forces contributed by each
story.
International Building Code 2305.3.8.2.9
Deflection of shear walls with openings.
The controlling deflection of a blocked shear
wall with openings uniformly fastened throughout
shall be taken as the maximum individual deflection
of the shear wall segments calculated in accordance
with Section 2305.3.2, divided by the appropriate
shear resistance adjustment factors of Table
2305.3.8.2.
International Building Code 2305.3.9
Summing shear capacities. The shear values for
shear panels of different capacities applied to the same side
of the wall are not cumulative except as allowed in Table
2306.4.1.
The shear values for material of the same type and
capacity applied to both faces of the samewall are cumulative.
Where thematerial capacities are not equal, the allowable
shear shall be either two times the smaller shear
capacity or the capacity of the stronger side, whichever is
greater.
Summing shear capacities of dissimilar materials
applied to opposite faces or to the same wall line is not
allowed.
Exception: Forwind design, the allowable shear capacity
of shear wall segments sheathed with a combination
of wood structural panels and gypsum wallboard on
opposite faces, fiberboard structural sheathing and gypsum
wallboard on opposite faces or hardboard panel
siding and gypsum wallboard on opposite faces shall
equal the sum of the sheathing capacities of each face
separately.