2012 irc wood wall bracing - umn ccaps irc wall bracing 21 base shear february 2008 macon co....

2012 IRC Wall Bracing 12/11/2017

Copyright 2013 International Code Council 1

2012 IRC Wood Wall Bracing2012 IRC Wood Wall Bracing2012 International Residential Code® (IRC®)

DescriptionDescription This 6-hour seminar provides a comprehensive

explanation of the 2012 International Residential Code® (IRC®) bracing requirements. It guides the participant through an in-depth review and analysis of the bracing requirements for wood-frame residential structures. The seminar is designed to clarify the application of wall bracing provisions in the IRC wall bracing Sections R602.10 – R602.12.

2012 IRC Wall Bracing 2

GoalGoal The participant will successfully apply the

provisions of the 2012 IRC to problems involving bracing requirements for wood-framed residential structures.


ObjectivesObjectives Upon completion, participants will be

better able to:1. Identify the forces that act on a house.2. Describe the history of bracing and how it

works.3. Apply the wall bracing provisions of the IRC.4. Grasp the physical limits under which

bracing can be used.




Objectives (continued)Objectives (continued)5. Select from the various bracing options

available.6. Determine how much bracing is required,

and how adjustment factors are applied.7. Recognize special considerations for

bracing.8. Apply attachment details, and pony and

cripple wall details.


Target AudienceTarget Audience Designers Plans examiners Inspectors Builders Contractors Architects & Engineers


ResourcesResourceswww.iccsafe.orgItem no. 7102S12

www.apawood.orgPublication F430


Bracing TopicsBracing Topics


Forces and History Limits Bracing Examples

Load Path

Lateral Forces

Stiffened Walls

Bracing History

Limits

Irregular Buildings

Wind Exposure

Locate BWL

Required Length

BWP Location

Panel Material & Ends

Sufficient Length

Connections

Foundation

Simplified Wall Bracing

Wind 90 mph, Exp B, SDC A

Wind 85 mph, Exp B, SDC D2

Wind 95 mph, Exp C, SDC B





Forces & History Limits Bracing Examples

Chapter 1 Chapter 4Chapter 2 Chapter 3




Load Path

Lateral Forces

Stiffened Walls

Bracing History

1. Ridge Beam

2. Post

3. Header

4. Jack Studs

5. Sill Plate

6. Foundation

7. Ground2012 IRC Wall Bracing 11

Load PathLoad Path

Vertical (Gravity) Load PathLoad LoadLoad


Load PathLoad Path

Lateral (Sideways) Load PathLoad LoadLoad




Load PathLoad Path

1. Load on wall

2. Transfer to roof

4. Transferto wall

5. Transfer to foundation

3. Connections


Load PathLoad Path

R301.1 Application The construction of buildings…shall result in a…complete load path…for the transfer of all loads…to the foundation.

Foundation3.7

Load

BracedWall

Panel

Foundations,IRC Chapter 4

Floors,IRC Chapter 5

Walls,IRC Chapter 6

Roof/Ceiling,IRC Chapter 8

Load PathLoad Path





Load Path

Lateral Forces

Stiffened Walls

Bracing Provisions



Lateral ForcesLateral Forces


Wind

Force =Pressure x Area

Force =Mass x Acceleration

Seismic

Resisted by hold-downs & Dead Load

Overturning

Resisted by Anchors

Base Shear

Resisted by Bracing

RackingEffects of Forces



Resisted by Bracing

Racking

Resisted by Anchors

Base Shear

Resisted by Hold-downs and Dead Load

OverturningEffects of Forces





Racking





Base Shear

February 2008

Macon Co.

‘Super Tuesday’ Tornado



Overturning

Anchors

hold-down





2003 Missouri Tornado





2003 Missouri TornadoLateral ForcesLateral Forces

2003 Missouri Tornado


Introduction: Lateral ForcesIntroduction: Lateral Forces


Wind Speed



Wind Speed – USA





Earthquake



SDC – United States




Load Path

Lateral Forces

Stiffened Walls

Bracing History

Stiffened WallsStiffened Walls


Wall FramingHinge

Hinge





Wall Framing

Panelresistanceimparted towall framing(Prevents hinging)

Interior Finish



Wall FramingWall FramingHinge

HingeBracedWall Panel(Prevents hinging)

(1) Areas requiring wind design in Table R301.2(4)B may not use the IRC for lateral provisions.



BWP (Prescriptive)

Limitations 3-Stories MaximumWind < 110 mph(1)

SDC A-D2Others (see IRC Chap. 3)

Typically withouthold-downs

Shear Walls (Engineered)

Applications Any building size/shapeWind – no limit SDC – no limit Calculations requiredTypically withhold-downs

VS.

Prescribedmaterial and nailing

Calculated load,material and nailing

Hold-downcapacity calculated



VS.BracedWall

Panel(BWP)

ShearWall



Wall BracingWall Bracing R602.10 Wall Bracing "Where a building, or portion thereof, does not

comply with one or more of the bracing requirements in this section, those portions shall be designed and constructed in accordance with Section R301.1.ʺ





Load Path

Lateral Forces

Stiffened Walls

Bracing History

History of BracingHistory of Bracing

Uniform Building Code – 1927 All exterior walls and partitions shall be thoroughly and effectively

angle braced.

Southern Building Code – 1946 Sheathing shall be applied on the exterior walls of buildings more than one story

in height, corners shall be braced by a let-in 1 x 4 or 1 x 6 continuous diagonal brace.

Uniform Building Code – 1952 All exterior walls and partitions shall be thoroughly and effectively angle braced

or sheathed with approved panels adequately nailed along all edges.


History of Wall BracingHistory of BracingHistory of Bracing




History of BracingHistory of BracingUniform Building Code – 1970

All exterior walls and main cross stud partitions shall be effectively and thoroughly braced at each end, or as near thereto as possible, and at least every 25 feet of length by on of the following methods:

A. Nominal 1-inch by 4-inch…B. Wood boards of 5/8-inch…C. Plywood sheathing…D. Fiberboard sheathing…E. Gypsum sheathing…F. Particleboard sheathing…

The Southern Building Code of 1970 had similar requirements as did the National Building Code by 1984.




History of BracingHistory of BracingUniform Building Code - 1994

32-inch alternate braced wall panel added


International Residential Code – 2000 Bracing percentage requirement added Continuous wood structural panel bracing method added

International Residential Code – 2006 Alternate braced wall panel adjacent to door or window opening added Continuous sheathing 4:1 and 6:1 aspect ratio panels at garage door added





History of BracingHistory of BracingInternational Residential Code – 2009

Methods renamed from number designation to abbreviation Wall bracing length determined by the greater length requirement from separate

wind and seismic bracing length tables Intermittent portal frame at garage added Continuous sheathing with structural fiberboard added Table of effective braced length for braced panels less than 48 in. long added Braced panel end distance limit of 12.5 ft. cumulative for SDC A-C with

intermittent bracing Additional bracing requirements for structures with masonry veneer moved to

wall bracing section Anchorage for masonry foundations with short wall lengths added Angled wall lines added Imaginary braced wall lines added


History of BracingHistory of BracingInternational Residential Code – 2012

Reorganization of wall bracing section Simplification of end distance and distance between braced wall panels Simplification of braced wall line length New method – Simplified Wall Bracing





?Questions

Load Path

Lateral Forces

Stiffened Walls

Bracing History




Limits

Irregular Buildings

Wind Exposure



Limits – Story HeightLimits – Story Height

2012 IRC Wall Bracing 49R301.3

In-plane lateral forces

Requirements for story height exist to limit the wind and seismic provisions

In-plane forces (lateral forces along a wall line):• Story height limit – 11 ft. 7 in• Stud height – 10 ft.

Except:Stud height may be increased to 12 ft., therefore maximum story height may be 13 ft. 7 in

Limits – Story HeightLimits – Story Height


StudHeight

StoryHeight

StoryHeight

16" Max Floor Framing(Joist Depth)

10' = Max. Stud Height(1)

16" = Max. Floor Framing Height(2)

(1)R301.3 – Item 1, Exception permits the stud height to be 12' provided bracing length is increased by a factor of 1.2.

(2)R301.3 Permits floor framing depths greater than 16ʺ when maximum story height is 11'-7ʺ or less.

R301.3

Limits – Stud HeightLimits – Stud Height


Stud Size

(Inches)

BEARING WALLS NONBEARING WALLS

Laterally unsupported stud height

(feet)

Maximum spacing when

supporting roof-ceilingassembly or

habitable attic, only (inches)


supporting one floor, plus a roof-ceilingassembly or

habitable attic (inches)


supporting two floors, aroof-ceilingassembly or

habitable attic (inches)


supporting one floor

height (inches)

Laterally unsupported stud height

(feet)

Maximum spacing (inches)

2 x 3 -- -- -- -- -- 10 16

2 x4 10 24 16 -- 24 14 24

3 x 4 10 24 24 16 24 14 24

2 x 5 10 24 24 -- 24 16 24

2 x 6 10 24 24 16 24 20 24

Size, Height and Spacing of Wood Studs - Table R602.3(5)

Limits – Story vs Stud HeightLimits – Story vs Stud Height


Balloon Framing Platform Framing

Stud Height

Story Height

Story Height

Stud Height

Stud Extends Two Stories

LateralSupport

R301.1.2



Limits - SeismicLimits - Seismic R301.2.2 Seismic provisions.

The seismic provisions of this code shall apply to… Townhouses in SDC C, D0, D1 and D2 Detached one and two family dwellings in SDC D0,

D1 and D2


Limits - SeismicLimits - Seismic


TownhouseSeismic requirements

apply

One- & two-familySeismic requirements

don't applyR301.2.2

Seismic Design Category C

Limits - SeismicLimits - Seismic


Wind Requirements Only

Wind and Seismic Requirements

Seismic Design Category

One- and two-family Townhouses

A & B N/A N/A

C N/A Seismic Req. Apply

D0 Seismic Req. Apply Seismic Req. Apply



R301.2.2

Limits - TownhouseLimits - TownhouseR202 TOWNHOUSE Three or more attached

units

Units extend from foundation to roof

Open space on at least two sides Open

two sides

R301.2.22012 IRC Wall Bracing 56



Limits - TownhouseLimits - TownhouseR202 TOWNHOUSE Three or more attached

units

Units extend from foundation to roof

Open space on at least two sides

Not open two sides(therefore, not a townhouse)


Limits - WeightLimits - Weight


R301.2.2.2.1 Weight of MaterialsAverage dead loads shall not exceed:

15 or 25 psf for roofs/ceiling assemblies 10 psf for floor assemblies 15 psf for exterior wall assemblies

Wind RequirementsWeight of materials

provisions do not apply

Seismic RequirementsWeight of materials

provisions apply

Limits - WeightLimits - Weight

2012 IRC Wall Bracing 59R301.2.3

Snow Load, R301.2.3Load Design Method

< 70 psf Prescriptive> 70 psf Engineered

Limits – Irregular BuildingsLimits – Irregular Buildings


R301.2.2.2.5 Irregular buildings

Wind Requirements

Irregular building provisions do not apply

Seismic Requirements

Irregular building provisionsapply

1 2 3 4 5 6 7Irregular building definitions



LimitsLimits


GroundSnowLoad

WindSpeed(mph)

SeismicDesign

CategorySubject to Damage From

WinterDesignTemp

Ice BarrierUnderlayment

Required

FloodHazards

AirFreezing

Index

MeanAnnualTemp

≤70 <110 A-D2Weathering Frost Line

Depth Termite

CLIMATIC AND GEOGRAPIC DESIGN CRITERIA - TABLE R301.2(1)




Limits

Irregular Buildings

Wind Exposure

Limits: Wind ExposureLimits: Wind ExposureR301.2.1.1 Wind Limitations and Wind Design Required

When wind speeds are 110 mph or greater OR When IRC Figure R301.2(4)B requires wind design


The following references may be used to design the walls to resist lateral forces:• WFCM• ICC 600• ASCE-7• AISI S230 (steel)• IBC R301.2.1.1

Limits: Wind ExposureLimits: Wind ExposureFigure R301.2(4)B shows where the IRC wall bracing requirements do not apply.

Another code or standard must be used to brace the walls against lateral loads.


Figure R301.2(4)B



Limits: Wind ExposureLimits: Wind ExposureR301.2.1 Wind Design Criteria Component and cladding loads for wall coverings,

windows, etc. per Table R301.2(2) and adjusted per Table R301.2(3) shall be used…


Figure R301.2(7)

Limits: Wind ExposureLimits: Wind Exposure

2012 IRC Wall Bracing 66Cladding Failure

R301.2.1 Wind limitations



Exposure A:Large city centers with at least 50 percent of the buildings having a height in excess of 70 feet for a distance of 0.5 mile upwind from the structure being designed.

70'Average

1/2 MileR301.2.1.4.1



Exposure B:Urban and suburban areas, wooded areas or other terrain with many closely spaced obstructions having the size of single family dwellings or larger.

R301.2.1.4.2





Exposure C (1 of 2):Open with scattered obstructions or undulations generally less that 30 feet in height extending for 1,500 feet in any direction.

>30'

R301.2.1.4.3



Exposure C (2 of 2):Within Exposure B terrain, but located directly adjacent to open areas of Exposure C for a distance of more than 600 ft..

More than600'

Exposure C terrain Exposure B terrain

R301.2.1.4.3



Exposure D:Flat, unobstructed areas exposed to wind flowing over open water for at least 1 mile. Extends inland 1,500 feet.

1 Mile 1,500'

R301.2.1.4.4




Limits

Irregular Buildings

Wind Exposure ?

Questions






Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Forces & History Bracing ExamplesLimits


Bracing: BWL SpacingBracing: BWL Spacing

Start End

AB

C

How many BWL's?


R202, R602.10.1, R602.10.2




1

2

LengthA B

Wid

th

LOAD

RES

ISTA

NC

E

RES

ISTA

NC

E

R602.10.1

Loaded wall versus resisting walls





1

2

LengthA B

Wid

th

LOAD

RESISTANCE

RESISTANCE

Loaded wall versus resisting walls



1

2

BWL SpacingA B

BW

L Sp

acin

g

WindBWL Spacing = 60' max.SeismicSDC C (only applies to townhouses)

BWL Spacing = 35' max.Permitted to be = 50' max. when bracing length increased.

Table R602.10.1.3

SeismicSDC D0, D1, & D2 (all dwellings)

BWL Spacing = 25' max.Permitted to be = 35' max. 1. To accommodate one

room not exceeding 900 ft2

2. For all BWLs when bracing length is increased and L/W < 3:1

Table R602.10.1.3


Bracing: BWL SpacingBracing: BWL Spacing Bracing: BWL SpacingBracing: BWL Spacing

21 32BWLSpacing

BWLSpacing

Locating BWL here makes distance between BWL's less.

2




Bracing: BWL SpacingBracing: BWL Spacing Wall Lines with BWP Offset Limitations Wall lines with BWP that are counted as part of a

BWL must be parallel to the BWL Offsets out-of-plane up to 4' are permitted for any wall

line There is an angle wall exception which will be

discussed later


R602.10.1.2 R602.10.1.2

1

2

A B


25'

20'

6'




4' BWL

R602.10.1.2



4'

4'

8'BWL

R602.10.1.2





4'

4'

A

B

24'

16'

C

R602.10.1.2



Wind 20' Edge to Edge "X" End BWP Width

6'

A

B

24'

16'

10' Max.

4'C

R602.10.1.2



25'

18'

6'Max.

6' Max.

R602.10.1.2

?



24'

BWP BWP3'

R602.10.1.2




Bracing: BWL SpacingBracing: BWL SpacingHow many BWL's?



24'

4'

R602.10.1.3 Angled Corners

Wall sheathing in a diagonal wall section may be counted for a wall line’s bracing length if the diagonal wall line is 8” or less in length.

R602.10.1.4



Angled Walls R602.10.1.4

Angle from BWL (degrees)

Projected BWL Length from Angled Wall Line

(ft.)Angled Wall Line

Length4 ft. 6 ft. 8 ft.

15 3.9 5.8 7.830 3.5 5.2 7.045 2.9 4.3 5.7 R602.10.1.4




Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Wind Speed Seismic Risk

Both wind speed and seismic risk must be considered when defining required wall bracing. The required bracing length is the greater of the two bracing lengths.

Bracing: Required LengthBracing: Required Length



Wind Requirements• Braced wall line spacing• Wall height• Eave to ridge height• Roof ties

Seismic Requirements• Wall length• Braced wall line spacing• Hold-downs• Material weight limits

When considering whether wind or seismic requirements control, a number of factors must be considered.

• Wall bracing length - either wind or seismic requirements may control. Use the longest required length.

• Hold-downs, Roof Ties, Limits – if wind or seismic requirements require additional connections or limits, they must be applied regardless of which requirement set controls.




R602.10.3, Tables R602.10.3(1), R602.10.3(2), R602.10.3(3) & R602.10.3(4)

Bracing Length Tables

2012 – Two bracing length tables• Wind Table R602.10.3(1) • Seismic Table R602.10.3(3)

Required bracing length is the maximum of the two tables’ bracing length x all adjustment factors



Bracing Required?

Wind Table R602.10.3(1)

All detached dwellings and townhouses

Seismic Table R602.10.3(3)

Detached dwellings in SDC

D0-D2

Townhouses in SDC C-D2

Decision Tree for Determining Required Bracing Length

R301.2.1, R301.2.2, R602.10.3





Table R602.10.3(1)

Bracing Requirements Based on Wind SpeedWind Bracing Table based on:

• Wind Exposure Category B• Mean roof height of 30 ft.• Eave to ridge height of 10 ft.• Wall height of 10 ft.• Two braced wall lines

Required bracing length is determined by:

• Wind speed• Story location• Wall line spacing• Bracing method


Adjust required bracing length

using Table R602.10.3(2)

Wind Exposure Category

Adjustment

Roof Eave to Ridge Height Adjustment

Wall Height Adjustment

# of BWLs Adjustment

Hold-down, Interior finish, GB fastener Adjustments

Adjustments to the required bracing length for wind forces:

Only required when adjustment is greater than 1.0 Table R602.10.3(2)




Table R602.10.3(2)

Bracing Requirements Based on Wind Speed –Adjustment Factors

Wind bracing adjustment factors are in Table R602.10.3(2)

1. Wind exposure category2. Eave-to-ridge height3. Wall height4. Number of braced wall lines5. 800-lb hold-down on top story6. Application of interior gypsum board finish7. Gypsum board fastening



Adjustment Factor –Wind Exposure Category, Mean Roof Height

Number of Stories

Exposure/Height FactorExposure B Exposure C Exposure D

1 1.0 1.2 1.52 1.0 1.3 1.63 1.0 1.4 1.7

Table R602.10.3(2)




Bracing: Required LengthBracing: Required LengthAdjustment Factor –

Roof Eave-to-Ridge Height

Support Condition

Roof Eave-to-Ridge Height< 5' 10' 15' 20'

Roof only 0.7 1.0 1.3 1.6Roof + floor 0.85 1.0 1.15 1.3

Roof + 2 floors 0.9 1.0 1.1 NPNP – Not Permitted

Roof sail area that contributes to total structure sail area

Eave-to-ridge height

Table R602.10.3(2)

Bracing: Required LengthBracing: Required LengthAdjustment Factor – Wall Height

Wall Height (ft.)

Adjustment Factor

8' 0.90

9' 0.95

10' 1.0

11' 1.05

12' 1.1

Table R602.10.3(2)



Bracing: Required LengthBracing: Required LengthAdjustment Factor – Number of Braced Wall Lines

Number of Braced Wall Lines

Adjustment Factor

2 1.0

3 1.30

4 1.45

> 5 1.60

x

xx

xxx

x – Braced wall line spacing– Braced wall line

Table R602.10.3(2)


Bracing: Required LengthBracing: Required LengthAdjustment Factor – Number of Braced Wall Lines

Footnote cNumber of Braced

Wall LinesAdjustment

Factor2 1.0

3 1.30

4 1.45

> 5 1.60

xx

xxx

x – Braced wall line spacing– Braced wall line

Table R602.10.3(2)

Table R602.10.3(2) Footnote c allows the adjustment factor to be 1.0 when the braced wall line spacing on exterior lines neglects the interior lines.

For example – when interior BWLs are only need for seismic bracing or when they are only needed to support BWLs in the story above.



Bracing: Required LengthBracing: Required LengthAdjustment Factors – wind cont.

AdjustmentFactor

BracingMethod

Adjustment Factor

Additional 800-lb hold-down at each BWP for top story only

DWB, WSP, SFB, PBS, PCP, and HPS 0.80

Interior finish DWB, WSP, SFB, PBS, PCP, HPS, CS-WSP, CS-G, and CS-SFB 1.4

Gypsum board fastening –4” o.c. at all panel edges, blocked horizontal joints

GB 0.7

Table R602.10.3(2)


Bracing TopicsBracing TopicsForces & History Bracing Examples

Locate BWL

Required Length

BWP Location


Sufficient Length

Support

Connections


Limits

?Questions


Bracing TopicsBracing TopicsForces & History Limits Bracing Examples

Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation




Bracing: BWP LocationBracing: BWP Location

R202, R602.10.1, R602.10.2

BWP, BWL & Spacing





6' 10'21' unbraced length

25' o.c.2'2'

4'BWP

4'BWP

BWP Spacing – 2009 and earlier



6' 10'20' unbraced length

R602.10.2.2

BWP Spacing – 2012 Edition



R602.10.2.2, R602.10.2.3

R602.10.2.2 Location of Braced Wall Panels,R602.10.2.3 Minimum Number of BWPs

BWL 1

10′ MAX

Placement Requirements BWP to begin no more than 10' feet from the end of a BWL. BWP located not more than 20' o.c. from edge to edge Two BWPs per BWL when BWL > 16 ft. ANDMinimum 1- 48″ BWP or 2- reduced length BWPs for BWL < 16 ft.

2012 IRC Wall Bracing 111 2012 IRC Wall Bracing 112


8' to 12'

Distance from Corner

Corner(end of wall line)

Wind Panel begins up to 10 ft. from the corner

R602.10.2.2, R602.10.2.2.1

Braced Panel Starting Location




Wall Bracing

Parameter

Intermittent CS-WSP CS-SFB

Wind & SDC A-C

SDCD0-D2

Wind & SDC A-C

SDCD0-D2

Wind & SDC A-C

SDCD0-D2

Panel end distance

12.5'Combined 0' or 8' (a) 12.5' 8' 12.5' Not

Permitted

Corner return length Not required 24" Min. (b) 32" Min. (b)

(a) For WSP, 8' with 24" panel at corner or 1,800 lb hold down per R602.10.1.4.1, exception items 1 & 2.

(b) In lieu of a corner return, an 800 lb hold-down may be fastened to the side of the BWP closest to the corner per R602.10.5.3, exception item 2.

Overview – 2009 and earlier



Wall Bracing

Parameter

Intermittent CS-WSP, CS-G, CS-PF CS-SFB

Wind & SDC A-C

SDCD0-D2

Wind & SDC A-C

SDCD0-D2

Wind & SDC A-C

SDCD0-D2

Panel end distance 10' 0' or 10' (a) 10' 10' 10' Not

Permitted

Corner return length Not required 24" Min. (b) 32" Min. (b)

(a) For WSP, 10' with 24" panel at corner or 1,800 lb hold down per R602.10.2.2.1, exception items 1 & 2.

(b) In lieu of a corner return, an 800 lb hold-down may be fastened to the side of the BWP closest to the corner per Figure R602.10.7, End Condition 2.

Overview – 2012 IRC

R602.10.2.2, Figure R602.10.7



2012 IRC Wall Bracing 115R602.10.2.2



12'-6" Max.

48"

Wind – 2009 IRC25' Centers"X" EndBWP length

25' Max.

R602.10.1.4, Figures R602.10.1.4(1) and R602.10.1.4(2)

48" 48"

Summary – 2009 Provisions





10' max

48"

Wind – 2012 IRC20' Spacing10' EndBWP length

20' max

R602.10.2.2

48" 48"

Summary – 2012 Provisions



Does this meet code?No, 20' maximum exceeded.

Wind – 2012 IRC20' Spacing10' EndBWP Width

R602.10.2.2

28'

48" 48"

Wind – 2012 IRC20' Spacing10' EndBWP Length



Does this meet code?Yes, 20' maximum not exceeded.

16'

36'

48" 48"48"

R602.10.2.2



Does this meet code?No, BWP required to begin no more than 10 feet from the end of the wall.


12'

36'

48" 48"

R602.10.2.2




3.7

Does this meet code?No, width requirement not met.

Wind & Seismic - 201220' Spacing10' EndBWP Width

R602.10.5

48" 48"

18'

2012 IRC


Bracing: BWP LocationBracing: BWP LocationDoes this meet code?

Yes, width requirements are met.


3.7Note: If BWP is supporting a story above, nailing must be a maximum 4ʺ o.c.

18'

8'

R602.10.6.1

28"

ABW

28"

ABW

ABW

Equals 4'


Bracing: BWP LocationBracing: BWP LocationDoes this meet code?

Yes, width requirements are met.

Wind & Seismic - 201220' Spacing10' EndBWP Width

3.7

Extended HeaderExtended Header

8' Note: Increase BWP width to 24" if supporting a story above.

R602.10.6.2

18'

16"

PFH

16"

PFH

Equals 4'

PFH



Locate BWL

Required Length

BWP Location


Sufficient Length

Support

Connections


Limits

?Questions





Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits


Bracing TopicsBracing TopicsBracing

Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation



Intermittent Bracing

Continuous Sheathing

Narrow Bracing

Mixed Methods

Interior Finish

Ends Conditions – Continuous Sheathing

Joints


Bracing: Panel Material -IntermittentBracing: Panel Material -Intermittent


Intermittent Bracing Methods:LIB - Let-in diagonal braceDWB - 3/4" Diagonal wood boardsWSP - 3/8" Wood structural panelBV-WSP – 7/16" Wood structural panel with stone or masonry veneerSFB - 1/2" Structural fiberboardGB - 1/2" Interior gypsum wallboard or gypsum sheathing particleboardPBS - 3/8" Particleboard sheathingPCP - Portland cement plaster on studsHPS - 7/16" Hardboard panel sidingABW - Alternate braced wallPFH - Portal frame with hold-downsPFG - Portal frame at garage door openings in SDC A-C

Table R602.10.4



Angled 45 to 60 degrees from horizontal

Extends continuously from bottom plate to top plate

1x4 lumber or approved metal strap

Application limited 8' to 10' wall height only 55" to

120"

8' to 10'

Table R602.10.4

Method LIB – Let-in Brace





Table R602.10.4




Must extend continuously from

bottom plate to top plate



8' to 12'

Method DWB – Diagonal Wood Boards Wood boards 3/4" (1" nominal)

thick applied diagonally Studs spaced 24" max.

4' min.Table R602.10.4




Method DWB – Diagonal Wood Boards




Method WSP – Wood Structural Panel 3/8" min. thickness Wood structural panel

defined in R604

8' to 12'

4' min.Table R602.3(3)



Method WSP – Wood Structural Panel

48"48" 48"


Method SFB – Structural Fiberboard Sheathing 1/2" or 25/32" thick Studs spaced 16" o.c. max. Must conform to ASTM C 208 Nailing 3" o.c. edge, 6" o.c. field

8' to 12'





Method SFB – Structural Fiberboard Sheathing




8' min.

Method GB – Gypsum Board 1/2" min. thick for studs

spaced 24" o.c. max. 4' minimum length Nailing at 7" o.c. Bracing length:

Single sided = 0.5 x actual length

Double sided = 1x actual length

No floating corners!

8' to 12'

Table R602.10.4




Method GB – Gypsum Board


Method PBS – Particleboard Sheathing 3/8" or 1/2" min. thickness Studs 16" o.c. max. 4' minimum length Nailing at 3" edge, 6" field Minimum 8d nails for 1/2"

thick sheathing8' to 12'



Bracing: Panel Material -IntermittentBracing: Panel Material -IntermittentMethod PCP – Portland Cement Plaster

Studs 16" o.c. max. Installed in accordance with R703.6 Nailing 6" o.c.

8' to 12'







Method PCP – Portland Cement


Method HPS – Hardboard Panel Siding• 7/16" minimum thickness• Studs 16" on center• Nailing 4" o.c. edge and

8" o.c. field

8' to 12'





Method HPS – Hardboard Panel Siding


Table R602.10.5 Minimum length for braced wall panels

48″ to 58″

BWP

BWP Height

BWPLengthMinimum Length of BWPs

Table R602.10.5

Method (See Table R602.10.4)

Minimum Lengtha

(inches) Contributing Length (inches)

Wall Height8 ft. 9 ft. 10 ft. 11 ft. 12 ft.

DWB, WSP, SFB, PBS,

PCP, HPS, BV-WSP

48 48 48 53 58 Actualb

GB 48 48 48 53 58

Double sided = Actual

Single sided = 0.5 × Actual

LIB 55 62 69 NP NP Actualb





Table R602.10.5.2 Effective length of braced panels less than 48"

For Methods DWB, WSP, SFB, PBS, PCP, HPS

ActualLength

Effective Length of BWP

8' 9' 10'48" 48" 48" 48"

42" 36" 36" N/A

36" 27" N/A N/A

27" to 48"

BWP

BWP Height

BWPLengthPartial Credit for Narrow BWPs

R602.10.5.22012 IRC Wall Bracing 145

Bracing: Panel Material -IntermittentBracing: Panel Material -IntermittentMethod ABW - Alternate Braced Wall

Equivalent to 48" panel For use on bottom story only Minimum length varies with SDC and

height Nailing:

Single story – 6" o.c. min Bottom of two story – 4" o.c. min

Minimum hold-down capacity changes with SDC and height

R602.10.6.1, Table R602.10.4



Length

Height

Method ABW - Alternate Braced Wall

Table R602.10.5

Minimum ABW LengthWall Height (ft.)

8 9 10 11 12SDC A-C 28 32 34 38 42SDC D0-D2

32 32 34 NP NP

Table R602.10.5 Minimum length for braced wall panels (excerpt)



Method ABW - Alternate Braced Wall Hold-down:

A prefabricated metal anchoring device that attaches the framing of a wall system to the structure below.The hold-down prevents uplift of the studs and, thus overturning of the wall segment.

Hold-down

Foundation reinforcement required(Caused by moment from hold-downs)





Min. 3/8" thick wood structural panel sheathing

#4 bars top and bottom for bracing

12" x 12" min. footing

Anchor bolts 1/2" (2)

Hold-down capacity per Table R602.10.6.1

Wind8' to 12'

SDC C, D0, D1and D2

8' to 10'

Figure R602.10.6.1

Method ABW - Alternate Braced Wall



Method PFH – Intermittent Portal Frame 16" min panel length for 1-story, 24" min for 2-story Header 6' min. to 18' max. Each vertical panel replaces a 48" braced wall panel

Extended header

16" or 24" min.

8' to 10'

R602.10.6.2, Table R602.10.5

PFH

PFH

PFH

Opening Opening



Min. 3/8" thick wood structural panel

(1) 5/8" anchor bolt

10' Max.

Extended header

3" o.c. nailing

4,200 lb strap type hold-down

1,000 lb strap capacity(opposite side from sheathing)

Method PFH – Intermittent Portal Frame

Figure R602.10.6.2


Method PFH with taller walls Wall height up to 12 ft. tall Portal height limited to 10 ft.

(top of header) Pony wall built above portal

header 4 ft. max pony wall height Pony walls require tension

straps (Table R60210.6.4) Number of jack studs

required for single portal post in Table R502.5(1)




Min. #4,200 hold-down

Min. 1,000 lbstrap(opposite side)

Figure R602.10.6.2


Min. 1,000 lbhold-down



Figure R602.10.6.2





For use in SDC A-C only Bracing length = 1.5 x length of panel

Minimum 24" length Header 6' min. to 18' max.

R602.10.6.3, Table R602.10.5

Method PFG – Intermittent Portal Frame at Garage

Min. 1,000 lb strap(opposite side from sheathing)

No hold-downs required

Extended header



Method PFG – Intermittent Portal Frame at Garage

Min. 7/16" thick wood structural panel

(2) 1/2" anchor bolts

10' Max.

Extended header

3" o.c. nailing

No hold-downs required

1,000 lb strap capacity(opposite side)

Figure R602.10.6.3




Method PFG with taller walls Wall height up to 12 ft. tall Portal height limited to 10 ft.

(top of header) Pony wall built above portal

header 4 ft. max pony wall height Pony walls require tension

straps (Table R60210.6.4) Number of jack studs

required for single portal post in Table R502.5(1)


Table R602.10.5 Minimum length for braced wall panels (excerpt)

Minimum Length of Narrow BWPs

Method (See Table R602.10.4)

Minimum Lengtha (inches) Contributing Length (inches)

Wall Height8 ft. 9 ft. 10 ft. 11 ft. 12 ft.

DWB, WSP, SFB, PBS, PCP, HPS, BV-WSP 48 48 48 53 58 Actualb

ABWSDC A, B and C 28 32 34 38 42

48SDC Do, D1 and D2 32 32 34 NP NP

PFHSupporting roof only 16 16 16 18c 20c 48Supporting one story

and roof 24 24 24 27c 29c 48

PFG SDC A, B and C 24 27 30 33d 36d 1.5 × Actualb


Bracing: Panel Material -ProprietaryBracing: Panel Material -ProprietaryOther bracing methods per code report Prefabricated units Laminated Kraft-paper board Fiberboard in various thicknesses




Bracing: Panel Material -ProprietaryBracing: Panel Material -Proprietary


Bracing Per Code Report

Bracing: Panel Material -ProprietaryBracing: Panel Material -Proprietary


Bracing Per Code Report


Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Mixed Methods

Interior Finish


Joints


Bracing: Panel Material -ContinuousBracing: Panel Material -Continuous Continuous Sheathing Bracing Methods:

CS-WSP Continuously sheathed wood structuralpanel

CS-G Continuously sheathed wood structural panel adjacent to garage openings

CS-PF Continuously sheathed portal frame CS-SFB Continuously sheathed structural

fiberboard


Table R602.10.4



Bracing: Panel Material -ContinuousBracing: Panel Material -ContinuousMain Concepts Allows for narrow

BWP's without hold-downs

BWL's must be fully sheathed with wood structural panel or structural fiberboard sheathing (continuously sheathed)


R602.10.4.2, Table R602.10.5

Bracing: Panel Material -ContinuousBracing: Panel Material -Continuous

R602.10.4.2 & R602.10.5

Sheathing Requirements:1. Sheath full height areas including gable ends2. Sheath above and below openings3. Adjacent openings determine minimum BWP length

Too Narrow


OpeningHeight

OpeningHeight


Figure R602.10.52012 IRC Wall Bracing 167


Aspect Ratio:The ratio of the height of a bracing unit to its length.

Length

Aspect Ratio = HeightLength

Aspect Ratio = 8'4'

= 2

Height

Table R602.10.52012 IRC Wall Bracing 168




BWP

20' Max.20' Max.

Infill Sheathing

R602.10.4 & Figure R602.10.52012 IRC Wall Bracing 169


R602.10.4.2, Table R602.10.4

Method CS-WSP Continuous Sheathing with Wood Structural Panel Area above and below openings fully sheathed including gable ends Min 3/8" wood structural panel sheathing

Method CS-SFB Continuous Sheathing with Structural Fiberboard Area above and below openings fully sheathed including gable ends Min 1/2" structural fiberboard sheathing



Wall Bracing Parameter

Continuously SheathedWood Structural PanelCS-WSP, CS-G, CS-PF

Continuously SheathedStructural Fiberboard

CS-SFB

Wind applicability < 110 mph ≤ 100 mph

Seismic applicability A - D2 A - C

Permitted wall heights 8' to 12' 8' to 12'

Corner return length(both sides of corner)

24" Min.(or hold downs at first BWP)

32" Min.(or hold downs at first BWP)

Panel end distance 10' 10'

Table R602.10.4, Figure R602.10.72012 IRC Wall Bracing 171


Table R602.10.5

Method CS-WSPFull-height sheathed wall segments having a length equal or greater than Table R602.10.5 are counted toward the total bracing length.

Wall minimum length is based on wall height and height of the adjacent clear opening.

Too Narrow




a. Garage opening adjacent to method CS-G panel shall have header. Max opening height includes header height.

b. Max header height 10 feet, pony wall may be used above header.


Bracing: Panel Material -ContinuousBracing: Panel Material -ContinuousMethod CS-WSP

Table R602.10.5

Method

Adjacent Clear

Opening Height (ft.)

Wall Height (ft.)

8 9 10 11 12

CS-WSP

64 24 27 30 33 3668 26 27 30 33 3672 27 27 30 33 3676 30 29 30 33 3680 32 30 30 33 3684 35 32 32 33 3688 38 35 33 33 3692 43 37 35 35 3696 48 41 38 36 36100 44 40 38 38104 49 43 40 39108 54 46 43 41112 50 45 43116 55 48 45120 60 52 48

Method

Adjacent Clear

Opening Height

(ft.)

Wall Height (ft.)

8 9 10 11 12

CS-WSP

124 56 51128 61 54132 66 58136 62140 66144 72

CS-G a 24 27 30 33 36CS-PF <120 16 18 20 22b 24b

Table R602.10.5 Minimum Length of Braced Wall Panels (in)


36'

All panels less than 20′ apart edge to edge

< 20' < 20' < 20'

8'

R602.10.4.2 & Table R602.10.5

Too narrow to be counted

24" 108" 32" 24"24"24"

Method CS-WSP



12' Max

H/4

Method CS-G Wood structural panel adjacent to garage opening Full-height sheathed wall segments to either side of garage openings Roof covering dead loads of 3 psf or less (seismic requirement only)

Applied to one wall line of garage only Panel length = bracing length 4:1 aspect ratio

R602.310.4, Table R602.10.5

GarageOpening



4:1 Aspect Ratio (24" min.)

Garage only, supportingroof with 3 psf covering.

Standard Header

Method CS-G





Garage

Opening

H/6

10' max(12' max

with pony wall)

Method CS-PF Continuous portal frameWalls on either or both sides of openings in garage may have wall segment with a maximum 6:1 height-to-length ratio.

R602.10.6.4

Fully sheathed dwelling

GarageOpening

No hold-downs required OK on raised floor Top of header at 10' max

Top of wall at 12' max Panel length = bracing length



Extended Header

6:1 Aspect Ratio (16" min.)

Garage only, story above permitted.

R602.10.6.4, Table R602.10.5

Method CS-PF




Figure R602.10.6.4

Method CS-PF

Bracing: Panel Material -ContinuousBracing: Panel Material -ContinuousMethods PFH, PFG and CS-PF

MINIMUM WALLSTUD FRAMINGNOMINAL SIZE

AND GRADE

MAXIMUMPONY WALL

HEIGHT (feet)

MAXIMUMTOTAL WALL

HEIGHT(feet)

MAXIMUMOPENING

WIDTH(feet)

BASIC WIND SPEED (mph)

85 90 100 85 90 100

Exposure B Exposure C

Tension strap capacity required (lbf)

2 × 4No. 2 Grade

0 10 18 1000 1000 1000 1000 1000 1000

1 109 1000 1000 1000 1000 1000 1275

16 1000 1000 1750 1800 2325 350018 1000 1200 2100 2175 2725 DR

2 10

9 1000 1000 1025 1075 1550 2500

16 1525 2025 3125 3200 3900 DR18 1875 2400 3575 3700 DR DR

2 129 1000 1200 2075 2125 2750 4000

16 2600 3200 DR DR DR DR

18 3175 3850 DR DR DR DR

Table R602.10.6.4: Tension Strap Capacity Required for Resisting Wind Pressures Perpendicular to 6:1 Aspect Ratio Walls





MINIMUM WALLSTUD

FRAMINGNOMINAL SIZE

AND GRADE

MAXIMUMPONY WALL

HEIGHT (feet)

MAXIMUMTOTAL WALL

HEIGHT(feet)

MAXIMUMOPENING

WIDTH(feet)

BASIC WIND SPEED (mph)

85 90 100 85 90 100

Exposure B Exposure C

Tension strap capacity required (lbf)

2 × 4No. 2 Grade 4 12

9 1775 2350 3500 3550 DR DR16 4175 DR DR DR DR DR

2 × 6Stud Grade

2 129 1000 1000 1325 1375 1750 2550

16 1650 2050 2925 3000 3550 DR

18 2025 2450 3425 3500 4100 DR

4 129 1125 1500 2225 2275 2775 3800

16 2650 3150 DR DR DR DR18 3125 3675 DR DR DR DR

Table R602.10.6.4 cont.: Tension Strap Capacity Required for Resisting Wind Pressures Perpendicular to 6:1 Aspect Ratio Walls

Methods PFH, PFG and CS-PF cont.


Plan View

Garage DoorGarage Door



R602.10.6.4

Method CS-PF

4

CS-G CS-PF




R602.10.5

Method CS-SFB Continuous Sheathing with Structural

Fiberboard

Wall minimum length based on wall height and height of adjacent clear opening

Maximum wall height = 12′ Length requirements for braced wall panels in Table R602.10.5 Same minimum bracing length requirements as CS-WSP Same aspect ratio (opening height limits) as CS-WSP





4:1 4:1 6:1 ~2:1

0% to 65%

H

0% to 65%

H

0% to 65%

H

18'

8'

R602.10.5.1

Too narrow to be counted

24"BWP

24"BWP

40"BWP

Method CS-SFB


18'

3:1 6:1 ~2.4:16:1

65%to

85% H

65%to

85% H

0%to

65%H8'


R602.10.5.2

32"BWP

40"BWP

Method CS-SFB Too narrow to be counted



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Mixed Methods

Interior Finish


Joints


Bracing Basics: Mixing Bracing MethodsBracing Basics: Mixing Bracing Methods


BWP method variation permitted from story to story with any type of sheathing

R602.10.4.1 Item 1

R602.10.4.1 Item 1



BWP method variation permitted from BWL to BWL within a story for intermittent sheathing

For continuous and intermittent sheathing, variation may only occur in SDC A-C with winds < 100 mph

R602.10.4.1 Item 2

R602.10.4.1 Item 2



BWP method variation within a BWL permitted ONLY in SDC A-B and for detached houses in SDC C with intermittent bracing

Greatest required bracing length for panel materials must be used.

Not applicable for use with continuous sheathing OR dwellings in SDC D0-D2

R602.10.4.1 Item 3

R602.10.4.1 Item 3



Mixing of CS-WSP, CS-G and CS-FP along a BWL is permitted in any SDC

R602.10.4.1 Item 4

R602.10.4.1 Item 4



BWP method variation in a BWL with continuous sheathing on exterior walls and intermittent on interior walls permitted ONLY in SDC A-B and for detached houses in SDC C Greatest required bracing length

for all panel materials in BWL must be used

Not applicable for dwellings in SDC D0-D2

R602.10.4.1 Item 5

R602.10.4.1 Item 5






Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Mixed Methods

Interior Finish


Joints


Interior Finish (Gypsum) Required½" thickness min

Exceptions:1. Wall panels braced with Methods GB, BV-WSP, ABW, PFH, PFG and CS-PF.2. When an approved interior finish material with an in-plane shear

resistance equivalent to gypsum board is installed.3. For all methods except LIB, omitting gypsum wall board is permitted when

the length of bracing in Tables R602.10.3(1) and R602.10.3(3) is multiplied by the factors in Tables R602.10.3(2) or R602.10.3(4).

BWP Material

R602.10.4.3 Braced Wall Panel Interior Finish Material

R602.10.4.3

Bracing Basics: Braced Panel ConstructionBracing Basics: Braced Panel Construction


Interior Finish (Gypsum) Required½" thickness min

Method LIB requires fasteners into interior finish at maximum 8" o.c.

Method LIB

R602.10.4.3 Braced Wall Panel Interior Finish Material

R602.10.4.3

Bracing Basics: Braced Panel ConstructionBracing Basics: Braced Panel Construction



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Mixed Methods

Interior Finish


Joints




Bracing: End ConditionsBracing: End Conditions

End Conditions – BWP at CornerCondition 1 - Return panel on perpendicular wall

Condition 2 - In lieu of a return panel, an 800 lb hold-down may be fastened to the corner stud.

Condition 3 - Minimum 48″ BWP, no return required

WSP return panel – 24″ minimumSFB return panel – 32″ minimum

R602.10.7

R602.10.7 End Conditions for Braced Wall Lines with Continuous Sheathing



End Conditions - BWP offset from corner

Condition 4 - Corner panel and return panel on perpendicular wall

Condition 5 - In lieu of a corner panel, an 800 lb hold-down may be

fastened to end of the BWP.

WSP return panel and corner panel – 24″ minimumSFB return panel and corner panel – 32″ minimum

R602.10.7

R602.10.7 End Conditions for Braced Wall Lines with Continuous Sheathing




Minimum required CS-WSP = 24"corner detail CS-SFB = 32"

Figure R602.10.7

18'

9' 84" 84"32" BWP

32" BWP

24"

Cor

ner

24"

Cor

ner

36" BWP

36" BWP

Continuous Sheathing Corner Requirements


Gypsum

BWP Material or Infill

16d nail at 12" o.c.

Gypsum

16d nail at 12" o.c.

Table R602.3(1) Item 8

Table R602.3(1) Item 8 - Corner Stud Requirements

BWP Material or Infill





Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation





Mixed Methods

Interior Finish


Joints


Bracing: JointsBracing: Joints


All vertical panel joints shall occur

over studs

Wood Structural PanelMethod WSP

GypsumMethod GB

R602.10.10

48"48"48"



Horizontal Blocking

R602.10.10 Panel jointsBlocking required at horizontal edges of BWP's.



Blocking is required at vertical edges of BWP's, except:

Exception 1 –Vertical panel joints may occur over doubled studs when nailed at 10″ o.c. with 10d box nails

Braced Wall PanelMethod WSP R602.10.10

48"

R602.10.10 Exceptions





Horizontal BlockingBlocking is required at horizontal edges of BWP's

Exceptions:2. Blocking at horizontal joints is not required in infill areas.3. Where the bracing length provided is 2x the minimum length required (Tables R602.10.3(1) and R602.10.3(3)) blocking at horizontal joints shall not be required in braced wall panels constructed using Methods WSP, SFB, GB, PBS or HPS.4. When Method GB panels are installed horizontally, blocking of horizontal joints is not required.

R602.10.10

R602.10.10 Exceptions


Locate BWL

Required Length

BWP Location


Sufficient Length

Support

Connections


Limits

?Questions



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits


Bracing: Sufficient LengthBracing: Sufficient Length


What is the minimum length of bracing allowed in a braced wall line?

(New) Section R602.10.2.3

BWL < 16 ft.: Minimum 2 BWPs any lengthOR 1 BWP 48″ long

BWL > 16 ft.: Minimum 2 BWPs





Determine whether there is sufficient space to place all the required bracing in a BWL

• Add length of qualified braced wall panel lengths• Check against required length• Locate space to place narrow panels if needed• Check end distances and spacing between panels

First, we will review panel lengths



Minimum panel width – OK Distance between panels – OK End distance – OK



Table R602.10.511'

3.748" 48"

Bracing Length = = 8′ 48" + 48"12"




18'

3.748" 48"36"

2006 - 48" min length requirement 2009/2012 - 36" braced panel is allowed with a reduced effective length

Bracing Length = = 10.25′ 48" + 27" + 48" 12"

Tables R602.10.5, R602.10.5.2

Min panel width Distance

between panels End distance





18'

3.7

16"

PFH

32"

ABW

Bracing Length = = 8′ 48" + 48"12"

Table R602.10.5




9'

18"40'

27" 27"18"

4'

2'Method CS- WSP

CS-WSPBottom of

Two Stories

90 mph SDC A

? NA

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5 40'

37'Wind Direction

Complete analysis

Basic Wind Speed (mph)

Story Location

Braced Wall Line Spacing

(ft.)

Minimum Total Length of Braced Wall Panels Required Along Each Braced Wall Line

Method LIB

Method GB (double sided)

Methods DWB, WSP, SFB, PBS, PCP, HPS


< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1) 2012 IRC Wall Bracing 216


9'

21"40'

48" 48"21"

4'

2'Method CS- WSP

CS-WSPBottom of

Two Stories

90 mph SDC A

12' NATotal Bracing Length = 11.5′ vs. 12′ Required

Bracing is insufficient(From Table – 40′ BWL)

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5





9'

21"40'

48" 48"21"

4'

2'Method CS- WSP

CS-WSPBottom of

Two Stories

90 mph SDC A

11.4' NA

Can interpolate for BWL spacing or for wall height.

0.95 x 12′ = 11.4′

Total Bracing Length = 11.5′ vs. 11.4′ Required

Bracing is OK

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5



8'

16'2' 2'

CS-GOne Story

90 mph SDC C? NA

Method CS-WSP

Garage Opening

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

20'

22'Wind Direction


Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)



8'

16'2' 2'

CS-GOne

Story

105 mph SDC C

5' NA

Method CS-G

Garage Opening

Total Bracing Length = 4′ vs. 5′ Required

Bracing is NG

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5




Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)



8'

16'2' 2'

CS-GOne

Story

105 mph SDC C

3.8' NA

Method CS-G

Garage Opening

Interpolate bracing length:5′ – 3.5′ = 1.5′ 1.5′ /10 = 0.15′ 3.5′ + 2x0.15′ = 3.8′Total Bracing Length = 4′ vs. 3.8′ Required

Bracing is OK

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5



PBSBottom of

Two Stories

90 mph SDC A

? ?

10'

4' 4'24'

16'

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

24'

42'Wind DirectionBasic Wind

Speed (mph)

Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)





PBSBottom of

Two Stories

90 mph SDC A

17′ NA

10'

4' 4'24'

16'

Total Bracing Length = 8′ vs. 17′ RequiredBracing is insufficient

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5


Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)



PBSBottom of

Two Stories

90 mph SDC A

14.6′ NA

10'

4' 4'24'

16'

Interpolated required bracing length:17′ – 14′ = 3′ 3′/10 = 0.3′14′ + 2x0.3′ = 14.6′Total Bracing Length = 8′ vs. 14.6′ Required

Bracing is insufficient

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5


36'

48" 48"

10'

SFBBottom of

Two Stories

90 mph SDC B

? NA

Method SFB

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

36'

20'Wind Direction





Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)



36'10'

Placement Requirement 4' + 4' = 8'

Wind Requirement7.5'

SFBBottom of

Two Stories

90 mph SDC B

7.5' NA

48" 48"

Wind Requirement 20' Centers 10' Ends BWP Width Bracing Length

Method SFB

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

7.5' < 8' 8 ft. required, 8 ft. available



36'7' 8' 6' 8' 7'

8'

PCPBottom of

Two Stories

105 mph SDC B

? NA

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

36'

25'Wind Direction Basic Wind Speed (mph)

Story Location


(ft.)


Method LIB

Method GB (doublesided)



< 110 (mph)

10 5.5 5.5 3 320 10 10 6 530 14.5 14.5 8.5 740 18.5 18.5 11 950 23 23 13 11.560 27.5 27.5 15.5 13.510 10.5 10.5 6 520 19 19 11 9.530 27.5 27.5 16 13.540 36 36 20.5 17.550 44 44 25.5 21.560 52.5 52.5 30 25.5



Table R602.10.3(1)





36'7' 8' 6' 8' 7'

8'

PCPBottom of Two

Stories

105 mph SDC B

16' NATotal Bracing Length = 20′ vs. 16′ Required

Bracing is OK

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

Bracing Basics: PercentageBracing Basics: Percentage

36'

10'

WSPBottom of Two Story

90 mph SDC B

? NA

48"

WSP 48"

WSP

Method WSP

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

36'

28'Wind Direction



Story Location


(ft.)


Method LIB




< 90 (mph)

10 3.5 3.5 2 220 7 7 4 3.530 9.5 9.5 5.5 540 12.5 12.5 7.5 650 15.5 15.5 9 7.560 18.5 18.5 10.5 910 7 7 4 3.520 13 13 7.5 6.530 18.5 18.5 10.5 940 24 24 14 1250 29.5 29.5 17 14.560 35 35 20 17



Table R602.10.3(1)



36'

10'



Wind 20' Centers 10' Ends BWP Width Bracing Length


90 mph SDC B

10.5' NA

48"

WSP 48"

WSP

Method WSP

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5




36'

10'



Wind 20' Centers 10' Ends BWP Width Bracing Length


90 mph SDC B

10.5' NA

48"

WSP 48"

WSP

Method WSP

Tables R602.10.3(1)&(2), R602.10.4, R602.10.5

60"

WSP

4' + 5' + 4' = 13'



Locate BWL

Required Length

BWP Location


Sufficient Length

Support

Connections


Limits

?Questions



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits


Item Building Element Number, Type and Spacing of Fastener

13 Double top plates, face nail 10d (3″ × 0.128″) @ 24″ oc

14Double top plates, minimum 24-inch offset of end joints, face nail in lapped area

8-16d (31/2″ × 0.135″)

15 Sole plate to joist or blocking, face nail

16d (31/2″ × 0.135″) @ 16″ oc

16 Sole plate to joist or blocking at braced wall panels

3-16d (31/2″ × 0.135″) @ 16″ oc

17 Stud to sole plate, toe nail 3-8d (21/2″ × 0.113″) or 2-16d (31/2″ × 0.135″)

18 Top or sole plate to stud, end nail 2-16d (31/2″ × 0.135″)

19 Top plates, laps at corners and intersections, face nail 2-10d (3″ × 0.128″)


Bracing: ConnectionsBracing: ConnectionsBWP sole plates and top plates connections per Table R602.3(1) Items 13-19

Excerpt from Table R602.3(1) Items 13-19



Bracing: ConnectionsBracing: Connections


When braced wall panels are perpendicular to joists above or below, blocking shall be provided in line with the BWPs…

R602.10.8 Item 1, Figure R602.10.8(1)

3.7BWP BWPBWP



(3) 16d nails at 16" o.c. along BWP16d (3-1/2" x 0.135")

8d toenailed at 6" o.c. 8d (2-1/2" x 0.113")

BWP Perpendicular to Framing

Figure R602.10.8(1) & Table R602.3(1)

Continuous band or rim joist below BWP

Full height blocking above and below BWP



Where joists are parallel to BWPs above or below… where a parallelframing member cannot be located… full-depth blocking at 16 inch spacing shall be provided…

BWP Blocking(not parallel)

R602.10.8 Item 2, Figure R602.10.8(2)


2012 IRC Wall Bracing 244Figure R602.10.8(2) & Table R602.3(1)

2-16d nails each side

8d nails toe-nailed at 6"o.c.

Full height blocking @ 16" o.c. above and below BWP

(3) 16d nails at16" o.c. along

BWP

BWP Parallel to Framing

3-8d nails toe-nailed at blocking @ 16" o.c.

(3) 16d nails at blocking @ 16" o.c.



SDC Wind Speed

Distance (bottom of roof sheathing

to top of plate)Blocking1

SDC A, B, C Wind < 100 mph

9.25" or less Not required, attach per R602.3(1)

9.25" to 15.25" Per R602.10.8.2.2 Item 1 and Figure R602.10.8.2(1)

SDC D0, D1, D2Wind > 100 mph 15.25" or less Per R602.10.8.2 Item 2 and

Figure R602.10.8.2(1)

All SDCsWind < 110 mph 15.25" to 48"

Per R602.10.8.2 Item 3 and Figure R602.10.8.2(2) or R602.10.8.2(3)



(1) Rafter or truss plate connection per Table R602.3(1)

R602.10.8.2

BWP Connection Requirements to Roof Framing


2012 IRC Wall Bracing 246Figure R602.10.8.2(1)

BWP Perpendicular to Rafters or Roof Trusses

For SDC A, B and C and wind speeds less than 100 mph, where

• 9.25″ < distance < 15.25″ to top of the rafters to perpendicular top plates

• The rafters connected to the top plates of braced wall panels with blocking

• In accordance with Figure R602.10.8.2(1) and attached using Table R602.3(1).




Figure R602.10.8.2(1)

For SDC D0, D1 and D2 or wind speeds of 100 mph or greater, where

• distance < 15.25″ to top of rafters or roof trusses to perpendicular top plates

• rafters or roof trusses shall be connected to the top plates of braced wall panels with blocking

• in accordance with Figure R602.10.8.2(1) and attached in accordance with Table R602.3(1)


Bracing: ConnectionsBracing: ConnectionsBWP Perpendicular to Rafters or Roof Trusses

For all Seismic Design Categories and wind speeds, where

• Distance > 15.25″ to top of rafters or roof trusses to perpendicular top plates

• Perpendicular rafters or roof trusses shall be connected to the top plates of braced wall panels in accordance with Figure R602.10.8.2(2) or Figure R602.10.8.2(3)

Roof Trusses per R802.10

Figure R602.10.8.2(2)




2012 IRC Wall Bracing 249Figure R602.10.8.2(3)

Roof Trusses per R802.10

Bracing



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits

?Questions



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits


Bracing: FoundationBracing: Foundation


Soil frictionLateral bearing capacity

Weight of the structure and footingBearing capacity of soil

Weight of soil

SlidingResisted by soil friction and lateral bearing capacity of soil.

OverturningResisted by weight of structure and footing, weight of soil on footing, and bearing capacity of soil.



Code Section Provision SDC A-C

High Seismic Regions SDC D0-D2

R602.10.6, Figures R602.10.6.1 and

R602.10.6.2

Alternate wall bracing (ABW,

PFH)

Methods ABW and PFH required 1-#4 horizontal top and bottom of footing

Methods ABW and PFH required 1-#4 horizontal at top and bottom of footing

R602.10.9, Figure R602.10.9

Short concrete or masonrywalls below

BWPs

Rebar required complying with Figure R602.10.9 if wall length, height, and thickness are L ≤ 48" AND H > 12" AND T < 6"

Rebar required complying with Figure R602.10.9 if wall length, height, and thickness are L ≤ 48" AND H > 12" AND T < 6

Wall Bracing – Foundation Requirements (R602.10)




3"

#4 bars at top & bottom

For footings supporting an ABW or PFH panel

R403.1.3.2

Wall Bracing Section Requirements




Narrow Masonry Wall RequirementsOnly required for walls

less than 48" long.


Main Concepts Code provisions defined in R602.9. Supported on continuous footings. There are two methods for determining the

required braced panel length for cripple walls (R602.10.11).

Cripple WallsCripple Walls

Cripple WallA framed wall extending from the top of the foundation to the underside of the floor framing of the first story above grade plane.



Bracing Length from Tables R602.10.3(1) or (3)

for Roof only

1.15 x (Roof only Bracing Length)



Cripple Wall Supporting One Story


for Roof only

Roof + Floor Bracing Length

Redesignated as a Two-story

or

R602.10.11

Seismic Design Categories A-D1

14' BWP edge to edge 20' BWP edge to edge


for Roof only

1.15 x (Roof + 1 Floor BP Length)


for Roof + 1 Floor

14' BWP edge to edge

Cripple Wall Supporting Two Stories

Redesignated as a Three Story

20' BWP edge to edge


for Roof only

BP length for Roof + 2 Floors


for Roof + 1 Floor

or



Seismic Design Categories A-D1



Cripple Wall or Story Above Grade?See Chapter 2 Definitions: Story Above Grade Grade Plane

Stacked framing not permitted





Bracing: FoundationBracing: FoundationFootings:

Anchor bolt placement Bolts embedded 7 inches Total length = 7” + plate(s) depth + threaded end

Footing depth Minimum 12 inches (R403.1.4) Frost depth controls in many areas

Footing width, W Table R403.1 lists minimum footing widths




6' Max.

7 bolt dia. min.to 12" max.

1/2" bolt with 7" min. embedment in concrete or masonry

End of Plate

R403.1.6



7"

1' 0"

6"

1' 0"

6" 7"

W W

T

P

3-1/2"

R403.1.1

Slab on Grade Raised Floor


Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits

?Questions





Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits


Bracing: Simplified Wall BracingBracing: Simplified Wall BracingPrescriptive Limits

The structure must meet the following requirements: Seismic Design Category (SDC) A, B, or C (SDC A or B for townhouses) Basic Wind Speed of 90 mph or less with Wind Exposure Category A or B One or two story structure Wood structural panel (WSP) or structural fiberboard sheathing (SFB) is used to

brace exterior walls with ½ in gypsum board fastened to the interior side of walls 60 ft. maximum length and width of the building Max eave-to-ridge height of 15 ft. Wall max height of 10 ft. Max ratio between long and short side of building: 3 to 1 Max cantilever of 24 inches beyond foundation No cripple walls in two story buildings



Bracing: Simplified Wall BracingBracing: Simplified Wall Bracing

Prescriptive Limits

WSP

1 or 2 story

SFBBraced Wall Panel

Material

Building Length


Advantages to the Simplified Method: No seismic requirements Bracing only occurs on the perimeter (exterior walls)

(No braced wall line length or spacing) No additional adjustment factors to check No interpolation





Procedure:

1. Draw a rectangle around the perimeter of the building and stagger the required number of bracing units along the four wall lines.



Rectangle Circumscribing an Enclosed Building

2012 IRC Wall Bracing 270Figure R602.12.1


Procedure cont.:

2. Identify the number of bracing units required on each side of the rectangle.


Bracing: Simplified Wall BracingBracing: Simplified Wall BracingMinimum Number of Bracing Units on Each Side of the Circumscribed Rectangle


Story Level

Eave-to Ridge Height(Feet)

Minimum Number of Bracing Units on Each Long Side a,b

Minimum Number of Bracing Units on Each Short Side a,b

Length of short side (ft.) c Length of long side (ft.) c

10 20 30 40 50 60 10 20 30 40 50 60

101 2 2 2 3 3 1 2 2 2 3 3

2 3 3 4 5 6 2 3 3 4 5 6

151 2 3 3 4 4 1 2 3 3 4 4

2 3 4 5 6 7 2 3 4 5 6 7

Table R602.12.4

a. Interpolation shall not be permitted.b. Cripple walls or wood-framed basement walls in a walk-out condition of a one-story structure

shall be designed as the first floor of a two-story house.c. Actual lengths of the sides of the circumscribed rectangle shall be rounded to the next highest

unit of 10 when using this table.




MaterialStud Spacing

& Fastener Criteria

Fastener Spacing Criteria

Bracing Unit Method

Minimum Bracing Unit Length (feet)

Wood Structural

PanelTable R602.3(3) 6'' edge

12'' fieldContinuous 3

Intermittent 4

Structural Fiberboard Sheathing

Max 16''spacing

Table R602.3(1)

3'' edge 6'' field

Continuous 3

Intermittent 4

Bracing Methods for Simplified Wall Bracing

a. Mixing of wood structural panel and structural fiberboard sheathing in one building is not permitted.b. Continuous and intermittent bracing units may be mixed from one story to another. c. Continuous and intermittent bracing unit methods may not be mixed within one story.

R602.12.2, R602.12.32012 IRC Wall Bracing 273


Narrow Bracing Method

Equivalent Bracing Units

CS-G 0.5CS-PF 0.5PFH 1PFG 0.75

Narrow Bracing Methods for Simplified Wall Bracing

Each narrow bracing method is worth one or less than one 3 ft. or 4 ft. bracing unit.

R602.12.6




Example SDC B Wind 90 mph, Wind Exposure B Method CS-WSP 1 Story Walls - 9 ft. Eave to ridge height - 12 ft.

Example Highlights: Strategic placement of bracing units

One Story

90 mph SDC B

NA

A B

49'-4"

2

1

59'-8"

1. Draw rectangle around the entire building

2. Check the length of the N-S and E-W sides the of rectangle

Less than 60 ft.?

OK




Bracing: Simplified Wall BracingBracing: Simplified Wall BracingTable R602.12.4 Minimum Number of Bracing Units


A B

49'-4"

2

1

59'-8" 1. 4 bracing units required along each wall line

2. With CS-WSP, the minimum bracing unit length is 3 ft.

3. Panels must be within 12 ft. of the end of wall line and within 20 ft. of one another.

Sufficient space?

Yes, CS-PF units are only worth 0.5 units each so 5 B.U.s min will be needed on the south wall.

Furthermore, 3 CS-PF are needed to space units less than 20 ft. apart.

10'-2"18' 19'-6" 12'

CS-WSP

CS-WSP

CS-PF CS-

PFCS-PF

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP


A B

4

1

59'-8"

Sufficient space?Yes, 4 CS-WSP bracing units fit along the east and west wall lines.

21'-8"

21'-2"

2

25'-2"

22'-2"

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP

CS-WSP



Locate BWL

Required Length

BWP Location


Sufficient Length

Connections

Foundation


Limits

?Questions




Bracing TopicsBracing TopicsForces & History ExamplesBracing






Limits


ExamplesExamples

Symbol Description

Diagonal let-in

Diagonal wood boards

Wood structural panel

Structural fiberboard

Gypsum wallboard

Particleboard

Portland cement

Hardboard

Symbol Description

Alternate BWP

Alt. BWP adj. opening

Continuous sheathing

Continuous 4:1

Continuous 6:1

Continuous sheathing

LIB

HBS

DWB

PBS

PCP

CS-G

ABW

PFH

CS-WSP

CS-PF

Symbol Key

CS-SFB

WSP

SFB

GB







Limits


Example: SDC A, Wind 90 mph, Exp BExample: SDC A, Wind 90 mph, Exp BExample Attributes: SDC A, Single-family dwelling Wind 90 mph, Wind Exposure B Method SFB Roof only (top of two stories) Wall height is 8 ft.

Example Highlights: Bracing percent based on wind. This structure is exempt from the seismic

requirements. BWP's on the second floor can be placed over an opening on the first floor. BWP's are permitted to occur up to 10 feet away from the ends of BWL's.


SFBTop

Story

90 mph SDC A



24'-11"

36'-10"A B

1

2

SFBTop

Story

Wall Line

90mph

SDCA

1, 2 5.5 ft.N/A

A, B 7.5 ft.

Upper Story


Exposure Category B30 ft. Mean Roof Ht.10 ft. Eave to Ridge

Ht.10 ft. Wall Height

2 Braced Wall Lines

Minimum Total Length (feet) of Braced Wall Panels Required Along Each Braced Wall Line

Basic Wind Speed

StoryLocation

Braced Wall Line Spacing(feet)

MethodLIB

Method GB

(double sided)

Methods DWB, WSP, SFB, PCP,

HPS

CS‐WSP,CS‐G, CS‐PF

< 90 (mph)

10 3.5 3.5 2.0 2.020 7.0 7.0 4.0 3.530 9.5 9.5 5.5 5.040 12.5 12.5 7.5 6.050 15.5 15.5 9.0 7.560 18.5 18.5 10.5 9.010 7.0 7.0 4.0 3.520 13.0 13.0 7.5 6.530 18.5 18.5 10.5 9.040 24.0 24.0 14.0 12.050 29.5 29.5 17.0 14.560 35.0 35.0 20.0 17.0

EXPOSURE CATEGORY B, 30 FT MEAN ROOF HEIGHT, 10 FT EAVE TO RIDGE HEIGHT,

10 FT WALL HEIGHT,2 BRACED WALL LINES

MINIMUM TOTAL LENGTH (feet) OF BRACED WALL PANELS REQUIRED ALONG EACH BRACED WALL LINE


Story Location


(feet)Method LIBf, h

Method GB (double sided)g

Methods DWB, WSP, SFB, PBS, PCP, HPSf,i


≤ 85 (mph)

10 3.5 3.5 2.0 1.5

20 6.0 6.0 3.5 3.0

30 8.5 8.5 5.0 4.5

40 11.5 11.5 6.5 5.5

50 14.0 14.0 8.0 7.0

60 16.5 16.5 9.5 8.0

10 6.5 6.5 3.5 3.0

20 11.5 11.5 6.5 5.5

30 16.5 16.5 9.5 8.0

40 21.5 21.5 12.5 10.5

50 26.5 26.5 15.0 13.0

60 31.5 31.5 18.0 15.5

10 NP 9.0 5.5 4.5

20 NP 17.0 10.0 8.5

30 NP 24.5 14.0 12.0

40 NP 32.0 18.0 15.5

50 NP 39.0 22.5 19.0

60 NP 46.5 26.5 22.5

≤ 90 (mph)

10 3.5 3.5 2.0 2.0

20 7.0 7.0 4.0 3.5

30 9.5 9.5 5.5 5.0

40 12.5 12.5 7.5 6.0

50 15.5 15.5 9.0 7.5

60 18.5 18.5 10.5 9.0

10 7.0 7.0 4.0 3.5

20 13.0 13.0 7.5 6.5

30 18.5 18.5 10.5 9.0

40 24.0 24.0 14.0 12.0

50 29.5 29.5 17.0 14.5

60 35.0 35.0 20.0 17.0

10 NP 10.5 6.0 5.0

20 NP 19.0 11.0 9.5

30 NP 27.5 15.5 13.5

40 NP 35.5 20.5 17.5

50 NP 44.0 25.0 21.5

60 NP 52.0 30.0 25.5

Minimum Required Length of BracingTable R602.10.3 (1)




2 Braced Wall Lines


Basic Wind Speed

StoryLocation


MethodLIB

Method GB

(double sided)


HPS


< 90 (mph)

10 3.5 3.5 2.0 2.020 7.0 7.0 4.0 3.530 9.5 9.5 5.5 5.040 12.5 12.5 7.5 6.050 15.5 15.5 9.0 7.560 18.5 18.5 10.5 9.010 7.0 7.0 4.0 3.520 13.0 13.0 7.5 6.530 18.5 18.5 10.5 9.040 24.0 24.0 14.0 12.050 29.5 29.5 17.0 14.560 35.0 35.0 20.0 17.0





Story Location






≤ 85 (mph)

10 3.5 3.5 2.0 1.5

20 6.0 6.0 3.5 3.0

30 8.5 8.5 5.0 4.5

40 11.5 11.5 6.5 5.5

50 14.0 14.0 8.0 7.0

60 16.5 16.5 9.5 8.0

10 6.5 6.5 3.5 3.0

20 11.5 11.5 6.5 5.5

30 16.5 16.5 9.5 8.0

40 21.5 21.5 12.5 10.5

50 26.5 26.5 15.0 13.0

60 31.5 31.5 18.0 15.5

10 NP 9.0 5.5 4.5

20 NP 17.0 10.0 8.5

30 NP 24.5 14.0 12.0

40 NP 32.0 18.0 15.5

50 NP 39.0 22.5 19.0

60 NP 46.5 26.5 22.5

≤ 90 (mph)

10 3.5 3.5 2.0 2.0

20 7.0 7.0 4.0 3.5

30 9.5 9.5 5.5 5.0

40 12.5 12.5 7.5 6.0

50 15.5 15.5 9.0 7.5

60 18.5 18.5 10.5 9.0

10 7.0 7.0 4.0 3.5

20 13.0 13.0 7.5 6.5

30 18.5 18.5 10.5 9.0

40 24.0 24.0 14.0 12.0

50 29.5 29.5 17.0 14.5

60 35.0 35.0 20.0 17.0

10 NP 10.5 6.0 5.0

20 NP 19.0 11.0 9.5

30 NP 27.5 15.5 13.5

40 NP 35.5 20.5 17.5

50 NP 44.0 25.0 21.5

60 NP 52.0 30.0 25.5



A B

1

2

24'-11"

36'-10"

BWP over opening below

8 ft.9' 4' 4' 10'

4 4

8 ft.

9' 4' 4' 7'4 4

SFBTop

Story

Wall Line

90mph

SDCA

1, 2 5.5 ft.N/A

A, B 7.5 ft.

Upper Story

OK

OK

SFB

SFB SFB

SFB




A B

1

2

24'-11"

36'-10"

8 ft.

4'

4'

4

4

8 ft.

4'

4'

10'

4

4

Upper Story

OKOK

SFB

SFB

SFB

SFB

SFBTop

Story

Wall Line

90mph

SDCA

1, 2 5.5 ft.N/A

A, B 7.5 ft.


A B

1

2

24'-11"

36'-10"

4'

4'

4'

4'

10'

9' 4' 4' 7'

9' 4' 4' 10'

4

4

4

4

4 4

4 4

SFBTop

Story

Wall Line

90mph

SDCA

1, 2 5.5 ft.N/A

A, B 7.5 ft.

Upper Story

SFB

SFB SFB

SFB

SFB

SFB

SFB

SFB


Example cont.: SDC A, Wind 90 mph, Exp BExample cont.: SDC A, Wind 90 mph, Exp BExample Attributes: SDC A, Single-family dwelling Wind 90 mph, Wind Exposure B Method SFB Roof plus 1 floor (bottom of two stories) Wall Height is 8 ft.


SFBBottom Story

90 mph SDC A

24'-11"

36'-10"A B

1

2

SFBBottom Story

Wall Line

90mph SDC A

1, 2 10.5 ft.N/A

A, B 14 ft.

Bottom Story




36'-10"

24'-11"

A B

1

2

36'-10"

4' 4' 4' 8'

12 ft.SFB SFB SFB

10' 6' 4'

10 ft.SFB

SFBBottom Story

Wall Line

90mph SDC A

1, 2 10.5 ft.N/A

A, B 14 ft.

OK

NG

Bottom Story

SFB

SFB SFB

SFB

SFB


36'-10"

24'-11"

A B

1

2

36'-10"

4' 4' 4' 8'

12 ft.SFB SFB SFB

10' 6' 4'

10 ft.SFB SFB

SFBBottom Story

Wall Line 90 mph SDC A

1, 2 9 ft.N/A

A, B 13 ft.

OK

OK

Bottom Story

SFB

SFB SFB

SFB

SFB

10.5' x 0.9 = 9'14' x 0.9 = 13'


A B36'-10"

24'-11"

1

2

3'

12.2

5 ft.

SFB

SFB

4′-6ʺ

12 ft

.

SFB

SFB

SFBBottom Story


1, 2 9 ft.N/A

A, B 13 ft.

NG NG

SFB 3′-6ʺ

4′-6ʺ

4′-6ʺ

5′-6ʺ

SFB

Bottom Story

The 3.5 ft. and 3 ft. segments qualify using Table R602.10.5.2

SFB

SFBSFB

SFB

SFB SFB


A B36'-10"

24'-11"

1

2

With the wall height adjustment, the required bracing length is 13 ft. x 0.9 = 11.7 ft.

3'

12.2

5 ft.

SFB

SFB

4′-6ʺ

12 ft

.

SFB

SFB

SFBBottom Story


1, 2 9 ft.N/A

A, B 11.7 ft.

OK OK

SFB 3′-6ʺ

4′-6ʺ

4′-6ʺ

5′-6ʺ

SFB

Bottom Story

SFB

SFBSFB

SFB

SFB SFB




A B36'-10"

24'-11"

1

2

3'

SFB

SFB

4′-6ʺSFB

SFB

SFBBottom Story


1, 2 9 ft.N/A

A, B 11.5 ft.

SFB 3′-6ʺ

4′-6ʺ

4′-6ʺ

5′-6ʺ

SFB

10' 6' 4'4 4

4' 4'4 4

4' 8'4

Bottom Story

SFB

SFB SFB

SFB

SFB

SFB

SFBSFB

SFB

SFB SFB








Limits


Example: SDC A, Wind 90 mph, Exp BExample: SDC A, Wind 90 mph, Exp B

Example 3 SDC A Wind 90 mph Method WSP & GB 1 Story 8 ft. tall walls, 10 ft. eave to ridge height

Example Highlights: Strategic placement of BWL's. Different bracing methods can be used together. Application of PFH

WSPOne

Story

90 mph SDC A

GBOne

Story

90 mph SDC A


17'-2" 17' 15'-7"

A

2

B C D27'-11"

28'-10"

27'-8"

4'8'

64'-6"

4'34

1

3'-8"

77'-8"2012 IRC Wall Bracing 300



17'-2" 17' 15'-7"

A

2

B C D27'-11"

28'-10"

27'-8"

4'8'

64'-6"

4'34

1

3'-8"

77'-8"2012 IRC Wall Bracing 301



2 Braced Wall Lines


Basic Wind Speed

StoryLocation


MethodLIB

Method GB

(double sided)


HPS


< 90 (mph)

10 3.5 3.5 2.0 2.020 7.0 7.0 4.0 3.530 9.5 9.5 5.5 5.040 12.5 12.5 7.5 6.050 15.5 15.5 9.0 7.560 18.5 18.5 10.5 9.010 7.0 7.0 4.0 3.520 13.0 13.0 7.5 6.530 18.5 18.5 10.5 9.040 24.0 24.0 14.0 12.050 29.5 29.5 17.0 14.560 35.0 35.0 20.0 17.0





Story Location






≤ 85 (mph)

10 3.5 3.5 2.0 1.5

20 6.0 6.0 3.5 3.0

30 8.5 8.5 5.0 4.5

40 11.5 11.5 6.5 5.5

50 14.0 14.0 8.0 7.0

60 16.5 16.5 9.5 8.0

10 6.5 6.5 3.5 3.0

20 11.5 11.5 6.5 5.5

30 16.5 16.5 9.5 8.0

40 21.5 21.5 12.5 10.5

50 26.5 26.5 15.0 13.0

60 31.5 31.5 18.0 15.5

10 NP 9.0 5.5 4.5

20 NP 17.0 10.0 8.5

30 NP 24.5 14.0 12.0

40 NP 32.0 18.0 15.5

50 NP 39.0 22.5 19.0

60 NP 46.5 26.5 22.5

≤ 90 (mph)

10 3.5 3.5 2.0 2.0

20 7.0 7.0 4.0 3.5

30 9.5 9.5 5.5 5.0

40 12.5 12.5 7.5 6.0

50 15.5 15.5 9.0 7.5

60 18.5 18.5 10.5 9.0

10 7.0 7.0 4.0 3.5

20 13.0 13.0 7.5 6.5

30 18.5 18.5 10.5 9.0

40 24.0 24.0 14.0 12.0

50 29.5 29.5 17.0 14.5

60 35.0 35.0 20.0 17.0

10 NP 10.5 6.0 5.0

20 NP 19.0 11.0 9.5

30 NP 27.5 15.5 13.5

40 NP 35.5 20.5 17.5

50 NP 44.0 25.0 21.5

60 NP 52.0 30.0 25.5



Use Table R602.10.3(1) to determine required bracing lengthExterior braced wall lines Add adjustment factor

BWL A – assume 20 ft. spacingMethod WSP = 4 ft. 4 x 1.45 x 0.9 = 5.2 ft.

BWL D – assume 50 ft. spacingMethod WSP = 9 ft. 9 x 1.45 x 0.9 = 11.7 ft.

BWL 1, 3, 4 – assume 30 ft. spacingMethod WSP = 5.5 ft. 5.5 x 1.45 x 0.9 = 7.2 ft.

Interior braced wall linesBWL B – assume 20 ft. spacing

Method GB = 7 ft. 7 x 1.45 x 0.9 = 9.1 ft.BWL C – assume 50 ft. spacing

Method GB = 15.5 ft. 15.5 x 1.45 x 0.9 = 20.2 ft.BWL 2 – assume 30 ft. spacing

Method GB = 9.5 ft. 9.5 x 1.45 x 0.9 = 12.4 ft.

Adjustment Factors:• Wind Exposure B = 1.0 • 4 BWLs = 1.45• Walls - 8 feet tall = 0.9• Eave to ridge height - 10 feet tall = 1.0

Total = 1.31

OneStory

Wall Line

90mph

SDCB

WSPAD

1, 3, 4?

NA

GBBC2

?


16'-2" 16' 14'-7"

A

2

B C D28'-5"

28'-10"

27'-8"

73'-8"4'3

4

3'-8"

4'8'

60'-6"

1

23.7

ft.

14.8

ft.

41 ft

.

25.2

ft.

GB

GB

OneStory

Wall Line

90mph

SDCB

WSP AD

5.211.7

NAGB B

C9.1

20.2

WSP

WSP

WSP

WSPWSP

23'-8"

9'-8"

15'-6"23'-0"

18'-0"

2'-9"equivalent

14'-2"

OK OK OK OK




17'-2" 17' 15'-7"

A

2

B C D27'-11"

28'-10"

27'-8"

77'-8"4'3

4

3'-8"

4'1

64'-6"

12 ft.

3 3

3 16 ft.8'

38 ft.

18 ft.

3

3

55

PFHPFH PFH

WSP

WSP

WSP

WSP

WSP

WSP

GB GB

WSP

OneStory

Wall Line

90mph

SDCB

WSP 1, 3, 4 7.2 ft.NA

GB 2 12.4 ft.

3WSP

6'

4'

20" typical

4'

4' 4'

4'

4'

4'

4'

4' OK

OK

OK

OK2012 IRC Wall Bracing 305







Limits

?Questions


307

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© International Code Council 2006

2012 IRC Wall Bracing



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