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Today’s Goals & Objectives

Understanding the need for bracing

Understand the requirements for

wall bracing in the 2012 IRC

Be able to perform a design, plan

review or inspection of bracing of

a wood framed dwelling

Illustrate some new tools for

designing/reviewing wall bracing

“What’s the big deal with

wall bracing? I have been

building this way for 20

years and have never had

a problem”

Prescriptive Residential Codes

Why do we have a

prescriptive code?

How does it differ from

an engineered design?

What is the basis for the

requirements?

Where might it fall

short?

Purpose of a Residential Code

R101.3

“…to safeguard the public

safety, health and general

welfare through

affordability, structural

strength…and safety to

life and property from fire

and other hazards

attributed to the built

environment.”

Engineered Design vs.

Prescriptive Construction

Engineered Design

• Design loads specific to each structure

• Load resisting elements are designed

using accepted engineering practice

Prescriptive Construction

• Generic loads for all structures within

the scope of the code

• Historical Performance

• Non-traditional engineering methods

Prescriptive Code

• Based on long

standing custom

• Historical

performance

• Typical

construction

materials

• Typical building

shapes

Typical?

2,434 ft² 2005

Average Home Size

2,095 ft² 1995

1,660 ft² 1973

1,000 ft² 1950

Source: Characteristics of Single Family Housing; Housing at the Millennium

Last 12 Years

(Z)

5

10

15

20

25

30

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Under 1400

Over 3000

Residential Design Trends

More wall openings

Larger rooms

Large openings in floor diaphragms

Weaker “non-structural” materials

Unique “architectural features”

Smaller building materials

Historical performance may not be

applicable to modern construction

Why Do We Need

Wall Bracing?

Overall Wind Effects

Load Path

Wind forces depend on

size of building

Graphics courtesy of APA-The Engineered Wood Association

1

1

2

3

The Sail Boat Story What makes a sail boat faster?

Building geometry affects the amount of wind force:

• The more surface area, the higher the wind loads.

How does wall

bracing work?

Wall Bracing Mechanics

Shear Wall Connections

Wall Bracing Connections

Lateral Loads

Wall Racking

Provide Shear Walls or Properly

Designed Wall Bracing

Lateral Load Damage: Racking

Foundation Sliding

Anchor building to foundation using

properly installed anchor bolts or other

approved alternate

Lateral and Uplift: Overturning

Provide holdowns at ends of

shearwall sections

Lateral Load Damage: Overturning

Review: Lateral Effects from

Wind or Earthquake

Shear/Sliding

Overturning

Racking

Purpose of Wall Bracing

How Does the Wall Bracing

System Work?

A Braced Wall Panel keeps the wall square by

transferring shear from the top of the wall to the bottom

Braced wall panels are built in a specific way

Braced wall panel has a specific amount of resistance

Panels are placed at specific locations within a braced

wall line to resist the lateral loads - typically the ends of

each braced wall line and at 25 ft o.c

Braced wall lines are placed at specific locations within

the structure

Wall Bracing

Requirements

of the 2012 IRC

2006 to 2009 Wall Bracing Revisions

Re-format

Allow greater flexibility

Add more narrow methods

Add illustrations

Reduce math (eliminate

percentages)

Correct bracing amounts for

wind resistance

2012 Wall Bracing Revisions

Re-re-format

Add/revise illustrations

Further simplify

Add CS-SFB bracing method

Add BV-WSP bracing method for

brick veneer in higher seismic

regions

Add Simplified Wall Bracing

Method R602.12

2012 IRC Wall Bracing Format:

R602.10. Braced Wall Lines: Location, offsets, and spacing

Braced Wall Panels: Construction, location,

number required, uplift load path

Required length of bracing

Braced wall panel construction methods

Braced wall panel minimum lengths

Braced Wall Line corner options

Braced Wall Panel Connections

Braced Wall Panels Support

Braced Wall Panel Joints

Cripple Wall Bracing

Simplified Wall Bracing provisions

R602.10 Wall Bracing

R602.10 Wall bracing. Buildings

shall be braced in accordance

with this section or, when

applicable, Section R602.12.

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.


How do you do that?

1. Place braced wall lines on structure

2. Place braced wall panels on the braced

wall lines

3. Construct the braced wall panels

correctly

How do you brace a house?

Easy as 1-2-3 1. Place braced wall lines on house

2. Place braced wall panels on walls

3. Construct braced wall panels properly

Braced Wall Lines


R602.10.1 Braced wall lines. For the purpose of

determining the amount and location of bracing

required in each story level of a building, braced

wall lines shall be designated as straight lines in

the building plan placed in accordance with this

section. – R602.10.1.1 Length of a braced wall line.

– R602.10.1.2 Offsets along a braced wall line.

– R602.10.1.3 Spacing of braced wall lines.

Length of Braced

R602.10.1.1 Length of a braced

wall line. The length of a braced

wall line shall be the distance

between its ends. The end of a

braced wall line shall be the

intersection with a perpendicular

braced wall line, an angled braced

wall line as permitted in Section

R602.10.1.4 or an exterior wall as

shown in Figure R602.10.1.1.

Braced Wall Lines: Offsets

R602.10.1.2 Offsets along a braced wall line. All

exterior walls parallel to a braced wall line shall be

offset not more than 4 feet from the designated braced

wall line location as shown Figure R602.10.1.1.

Interior walls used as bracing shall be offset not more

than 4 feet from a braced wall line through the interior

of the building as shown in Figure R602.10.1.1.

Braced Wall Lines: Spacing

R602.10.1.3 Spacing of braced wall lines. The

spacing between parallel braced wall lines shall be in

accordance with Table R602.10.1.3. Intermediate

braced wall lines through the interior of the building

shall be permitted.

R602.10.1.4 Angled walls. Any portion of a wall along

a braced wall line shall be permitted to angle out of

plane for a maximum diagonal length of 8 feet. Where

the angled wall occurs at a corner, the length of the

braced wall line shall be measured from the projected

corner as shown in Figure R602.10.1.4.

Where the diagonal length is greater than 8 feet, it shall

be considered a separate braced wall line and shall be

braced in accordance with Section R602.10.1.

Braced Wall Lines: Angled Walls

Braced Wall Lines: Easy as 1-2-3

BWL is a straight line through the

building plan view. They do not have

to be on a wall

All exterior walls must be within 4’ of a

BWL (4’ maximum offset permitted)

BWL spaced a maximum of 60’ O.C.

Wall Bracing Example: BWL

Example:

1) All Exterior Walls Part of a BWL

52 ft

60 ft

40 ft

8 ft

12 ft

20 ft

20 ft25 ft

60 ft

Example:

2) BWL Spaced a Max. of 60’ O.C.

52 ft

60 ft

40 ft

8 ft

12 ft

20 ft

20 ft25 ft

60 ft

52 ft

60 ft

40 ft

8 ft

12 ft

20 ft

20 ft25 ft

60 ft

Example:

3) 4’ Max. Offset from BWL

Where do they go?

How do you build them?

≤ 25’ ≤ 25’ ≤ 25’

Braced Wall Panels:

Braced Wall Panels:

What are they?

1. Intermittent

2. Continuous

3. Narrow Alternates

Intermittent

Wood

Structural

Panel

Bracing

Same 8 Braced Wall Panel Methods:

Intermittent BWP – R602.10.2

1. LIB - 1x4 Let in Brace

2. DWB - Diagonal Wood Boards

3. WSP - Wood Structural Panels

4. SFB - Structural Fiberboard

5. GB - Gypsum Board

6. PBS - Particleboard

7. PCP - Portland Cement Plaster

8. HPS - Hardboard Panel Siding

Braced Wall Panels:

Table R602.10.2

Intermittent Bracing Methods

Method LIB:

1x4 Let In Bracing

Installed at an angle of

45°- 60° from

horizontal

Min wall length = 8’-6” to

5’-1” for 8’ wall

2-8d nails at each stud

and plate

R602.10.2 Intermittent braced

wall panel construction

Method LIB continued:

Metal Wall Brace

Installed at an angle of 45°- 60° from horizontal

Min wall length =

– 5’-0” for WB for 8’ wall

– 5’-6” for RCWB for 8’ wall

Install in pairs in “X” or “V” for flat strap style

Install only one for “let in” style

Nailing to each stud and plate per manufacturer



Braced Wall Panels: LIB



Method WSP:

Wood Structural

Sheathing

Min wall length = 48”

3/8” min thickness OSB

or Plywood

6” O.C. edge nailing

12” O.C. field nailing

WSP Fastening


wall panel construction Method SFB:

Structural Fiberboard Sheathing

Min wall length = 48”

1/2” min thickness structural fiberboard

3” O.C. edge nailing

6” O.C. field nailing

All Panel Edges to be blocked

Fasteners:

•1½” galv. roofing nail

•8d common nail

Method SFB:

Structural Fiberboard Sheathing



Method GB: Gypsum Board 1/2” min thickness

Fastening: Nails or screws

at 7″ spacing at panel

edges including top and

bottom plates; for all

braced wall panel locations

for exterior sheathing nail

or screw size, see Table

R602.3(1); for interior

gypsum board nail or

screw size, see Table

R702.3.5 Min wall length = 96”

for single sided

Min wall length = 48” for double sided

b. Screws shall be in accordance with Section R702.3.6.

R702.3.6 Fastening. Screws for attaching gypsum board to

wood framing shall be Type W or Type S in accordance with

ASTM C 1002 and shall penetrate the wood not less than 5/8

inch (16 mm).

Interior Gypsum Board Fastening

Exterior Gypsum Sheathing Nailing:

Table 602.3(1)

Other Methods

”

Method DWB

Diagonal Boards

5/8” minimum thickness

•8d nails or 1¾” staples,

•2 to each stud

PBS

1-1/2″ galvanized roofing nails or 8d common

(2-1/2″ × 0.131) nails at 3″ spacing (panel

edges) at 6 spacing (intermediate supports)

Other Methods

Method HPS

Hardboard Panel Siding

Method PCP

1-1/2″, 11 gage, 7/16″ head nails at

6″ spacing or 7/8″, 16 gage staples at

6″ spacing 0.092″ dia., 0.225″ head nails with length to

accommodate 11/2″ penetration into studs at 4″ spacing

(panel edges), at 8″ spacing (intermediate supports)

Proprietary Methods Brace-o-

Brace-o-ply

Brace-O-Ply

The Magic Bracing Company

Braceville, USA

R602.10.2.1 Intermittent braced wall

panel interior finish material

Intermittent braced wall panels shall have gypsum

wall board installed on the side of the wall opposite

the bracing material. Gypsum wall board shall be

not less than 1/2 inch in thickness and be fastened

in accordance with Table R702.3.5 for interior

gypsum wall board.

Exceptions:

1. Wall panels that are braced in accordance with Methods

GB, ABW, PFG and PFH.

2. When an approved interior finish material with an in-plane

shear resistance equivalent to gypsum board is installed.

3. For Methods DWB, WSP, SFB, PBS, PCP and HPS,

omitting gypsum wall board is permitted provided the length

of bracing in Tables R602.10.1.2(1) and R602.10.1.2(2) is

multiplied by a factor of 1.5.

Braced Wall Panels:

Minimum Lengths

Minimum Lengths:

Table R602.10.3.1

Partial Credit:

Table R602.10.3

Alternate Braced Wall Panel

Most braced wall panels have

minimum lengths of 48” or

more

Alternate Braced Wall Panels

allow lengths less than 48”

So what are

our biggest

challenges?

GARAGE RETURNS

Garage Openings

GARAGE RETURNS

Usually the weakest

part of the building

Typical width of

12”-24”

Less than 2’-4”

minimum required

by code for

prescriptive

methods or 4:1

when supporting

light roof only

Not enough wall space

Effect of Narrow Panels

Alternate Braced Wall Panel

Most braced wall panels have

minimum lengths of 48” or

more

Alternate Braced Wall Panels

allow lengths less than 48”

To make up for reduced width,

have to have restraint to keep

from overturning

ABW

Type 1:

One Story Building

Replaces 4’ Braced Wall

Minimum Length of 2’-4”

Maximum Height of 12’

Sheath with 3/8” min W.S.P.

6” O.C. 8d edge nailing

12” O.C. 8d field nailing

2 Anchor Bolts

2 Holdowns

Reinforced Foundation

ABW

Type 2:

First Story of Two-

Story Building

All the requirements of

Type 1 plus:

Nail at 4” o.c. at edges

instead of 6” o.c.

2 Holdowns

Three Anchor Bolts

Figures instead of text

Minimum Widths & Tie-Down Forces of Alternate Braced Wall Panels

Seismic Design

Category and

Windspeed Tie-Down Force (lb)

Height of Braced Wall Panel

Sheathed Width

8 ft 9 ft 10 ft 11 ft 12 ft

2'-4" 2'-8" 2'-8" 3'-2" 3'-6"

SDC A-C

Windspeed < 110

R602.10.6.1, Item 1 1800 1800 1800 2000 2200

R602.10.6.1, Item 2 3000 3000 3000 3300 3600

SDC D (all)

Windspeed < 110

Sheathed Width

8 ft 9 ft 10 ft 11 ft 12 ft

2'-8" 2'-8" 2'-8" 3'-2" 3'-6"

R602.10.6.1, Item 1 1800 1800 1800 --- ---

R602.10.6.1, Item 2 3000 3000 3000 --- ---

ABW Minimum Widths of Alternate Braced Wall Panel

Simpson Components from

T-WALLBRACE

•Portal with holdowns

•Replaces 4’ of braced wall panel

•Must be adjacent to a window or

door opening with a full-length

header

Method PFH

Alternate Panel Size

• Height of not more than 10 feet

• One story buildings –

– minimum length of 16”

• First of two story buildings –

– minimum length of 24”

PFH

Sheathed on one face with a single layer of 3/8” minimum-thickness wood structural panel sheathing

Nailed with 8d common or galvanized box nails in accordance with Figure R602.10.6.2.

PFH

The wood structural panel sheathing extends up over the solid sawn or glued-laminated header and is nailed in accordance with Figure R602.10.6.2.

The header extends over and rests on studs at each side of opening.

PFH

The clear span of

the header not

less than 6’ and

not more than

18’ in length.

A 1000 pound

strap installed

from the header

to the inner

studs opposite

the sheathing.

PFH

1000 LB. STRAP

INSTALLED TO

FRAMING AND

HEADER OPPOSITE

SHEATHING

One anchor bolt not less than 5/8” diameter installed in the center of a triple sill plate

Embedded strap type tie-down device (holdown) with a min. capacity of 4,200 lbs. installed to the studs at each end of the panel.

PFH

PFH

Panels supported directly on a

foundation or on floor framing

supported directly on a

foundation, which is continuous

across the entire length of the

braced wall line.

The foundation reinforced with not

less than one No. 4 bar top and

bottom.

Portal Frame Garage (PFG):

R602.10.3.4 (Intermittent)

Minimum Width:

8-ft = 24-in

9-ft = 27-in

10-ft = 30-in

Sheathing Nailed to all

Studs, Plates, Blocking

with 8d Common Nails

at 3” O.C.

Splices Shall Occur Within

24” of Mid-height and

Edges Shall be Blocked

2 Rows of 16d Sinkers

Nails at 3” O.C.

1000 lb Header Strap

Minimum 3” x 11¼”

Continuous Header

Two Anchor Bolts

with 2½”x2½”x3/16”

Plate Washers

7/16” Min. Thickness

Wood Structural Panel

Sheathing

Min (2) 2x4

2x Top Plate

10’

Max

Full Height Outer Stud

Nailed to Header with

6-16d Sinkers

Sheathing Nailed to

Header with 8d Nails

in 3” Grid Pattern

• SDC A-C

• Adjacent to Garage Door Opening

• Directly on Foundation

Use wall

length x 1.5

when

determining

bracing

amounts

Method PFG

Simple right?

Problems anywhere else?

Challenges with minimum panel

width?

Continuously Sheathed Wall

IRC Introduced new bracing concept

All areas of all walls fully sheathed with wood

structural panel sheathing, including above

and below all openings

– Lengths less than 4’ allowed

– Reduced bracing amounts allowed

– Specific exemption for garage return

3/8” WSP Sheathing

Above and Below all Openings

6”/12” O.C. Nailing

Braced Wall Panels:

Continuous Sheathing – R602.10.4

Similar Table for Continuous Methods

Continuously Sheathed Method:

Minimum Lengths

2009 Req’d Length Table

Continuously Sheathed Method:

Minimum Lengths (2012)

Special corner framing Figure R602.10.4.4(1)

Continuously Sheathed Method

Special corner framing

24” panel each side of corner



Special corner framing not present


Special corner framing-

first panel doesn’t meet width rqmts


Special corner framing-

First panel not at corner


Special corner framing

800-pound hold-down fastened

to foundation or framing below

Straps to framing below

Anchor

connecting to

foundation

Effect of Narrow Panels

Continuously Sheathing:

3 Primary Benefits

Braced wall panels can be

narrower than 48”

Braced wall lengths are

reduced

Method CS-G can be used at

garages of one-story homes

Method CS-PF can be used at

openings

Garage returns too small?

Windows too close to corners?

Too much glass on back/front of

house?

What if I STILL can’t meet the min.

braced wall panel requirements?

Narrow Continuous Methods

Continuously Sheathed - Garage

Wall supporting light framed roof only

Adjacent to a garage

3/8” minimum Continuous WSP

One wall of a garage only

10-ft max Height

No special construction req’d

Wall

Height

Min.

Length

8-ft 24-in

9-ft 27-in

10-ft 30-in

CS-PF Walls on either or both sides of openings attached to fully sheathed dwellings shall be permitted to be built similar to PFG EXCEPT

•a single bottom plate is used

•two anchor bolts are placed at 1/3 points of sill plate.

CS-PF •Tie-down devices are not required

•The vertical wall segment has a minimum

width per Table R602.10.4.2

H

W

(H/W≤6)

Continuous Portal Frame (CS-PF):

R602.10.4.1.1

Minimum Width:

8-ft = 16-in

9-ft = 18-in

10-ft = 20-in

Sheathing Nailed to all

Studs, Plates, Blocking

with 8d Common Nails

at 3” O.C.

Splices Shall Occur Within

12” of Mid-height and

Edges Shall be Blocked

2 Rows of 16d Sinkers

Nails at 3” O.C.

1000 lb Header Strap

Minimum 3” x 11¼”

Continuous Header

Foundation:

Two Anchor Bolts with

2”x2”x3/16” Plate Washers

Wood Floor:

Two 670-lb Framing

Anchors or Overlapped

Sheathing

3/8” Min. Thickness

Wood Structural Panel

Sheathing

Min (2) 2x4

2x Top Plate

10’

Max

Full Height Outer Stud

Nailed to Header with

6-16d Sinkers

Sheathing Nailed to

Header with 8d Nails

in 3” Grid Pattern

Use actual

wall length

when

determining

bracing

amounts

CS-PF Alternate Anchorage for

Upper Story Walls

Braced Wall Panels:

Narrow Alternates

Alternate Braced Wall (ABW),

R602.10.3.2

Portal Frame with Hold-Downs

(PFH), R602.10.3.3

Portal Frame at Garage Opening

(PFG), R602.10.3.4

Continuous Sheathed Portal Frame

(CS-PF), R602.10.4.1.1

Continuous Sheathed at Garage

Opening (CS-G), R602.10.4

Inte

rmitte

nt

Contin

uo

us

BIG CHANGE:

AMOUNT OF BRACING

No longer just a percentage

(16%)

Based on either

• BWL spacing for wind

• BWL length for seismic

Wall Bracing Amounts

2009 IRC Wind Hazard Map

Amount of Bracing:

WIND

R602.10.1.2(1)

SEISMIC

R602.10.1.2(2)

A) Amount of Bracing:

Table R602.10.1.2(1)

Adjustment Factors

•Wind Force •Projected Area •Bracing Strength

Adjustment Factors: Exposure

Wind Exposures:

Consult your local

building department for

site classification!

Exposure B

Numerous closely spaced obstructions having the size of

single-family dwellings or larger.


Exposure C

Open terrain extending more than 1500 feet in any quadrant.

Exposure C extends 600 feet into adjacent exposure B type

terrain. Includes flat open country, grasslands, and shorelines

in hurricane prone regions.


Exposure D

Exposed to wind flowing over open water for a distance of at

least 1 mile. Extends inland 1500 feet. Excludes shorelines in

hurricane prone regions. Includes inland waterways and Great

Lakes.


Adjustment Factors: Ridge Height

Wall

Height

Wall

Height

Wall

Height

Eave-to-

Ridge

Height

BWL Supporting

Roof Above

BWL Supporting

Roof and One

Story Above

BWL Supporting

Roof and Two

Stories Above

Adjustment Factors: Wall Height

• 0.90 for 8’

• 0.95 for 9’

• 1.00 for 10’

• 1.10 for up to 12’

Wall

Height

Wall

Height

Wall

Height

Eave-to-

Ridge

Height

BWL Supporting

Roof Above

BWL Supporting

Roof and One

Story Above

BWL Supporting

Roof and Two

Stories Above

Adjustment Factors: No. of BWLs

BWL

C

BWL

B

BWL

A

BWL

Spacing

BWL

Spacing

Number of BWLs

Wall Bracing for Wind 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

BASIC WIND SPEED

STORY LOCATION

BRACED WALL LINE SPACING

(FT)

METHOD LIB

f,h

METHOD GB (DOUBLE

SIDED)g

METHODS DWB, WSP, SFB, PBS, PCP, HPS

i

CONT. SHEATHING

≤ 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

60 X 30 Bldg. 2 braced wall lines, Spacing = 60 feet

Bracing req’d for WSP = 10.5’

Total bracing = 2 X 10.5 = 21’



2 BRACED WALL LINES


BASIC WIND SPEED

STORY LOCATION


(FT)

METHOD LIB

f,h

METHOD GB (DOUBLE

SIDED)g


i

CONT. SHEATHING

≤ 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



Total bracing = 3 X 5.5 = 16.5’ (less than 21’ required)

Adjustment Factors:

800-Pound Tie-Down 0.80 for top-most story only

Each end of each BWP in BWL

Fastened to foundation or framing

below

Straps to framing below

Anchor

connecting to

foundation

Adjustment factor: Gypsum on

inside face of BWP

f. Bracing lengths are based on the application of gypsum board finish (or equivalent) applied to the inside face of a braced wall panel. When gypsum board finish (or equivalent) is not applied to the inside face of braced wall panels, the tabulated lengths shall be multiplied by the appropriate factor from the following table:

Bracing Method Adjustment Factor

Method LIB 1.8

Methods DWB, WSP, SFB, PBS, PCP, HPS 1.4

Seismic Bracing Table

Seismic adjustments all in one

table

A) Amount of Bracing:

R602.10.1.2 Length of Bracing

In no case shall the

minimum total length of

bracing in a braced wall line,

after all adjustments have

been taken, be less than 48

inches total.

Braced Wall Panel Placement

Easy as A…..B……C

A. Amount (LENGTH) of

bracing

B. Spacing between panel

edges

C.Placement at ends of

wall lines

A) Amount of Bracing

A B C D

Amount = A + B + C + D

(Each segment must meet

minimum width rqmts.)

B) Braced Wall Panel Spacing

C) Braced Wall Panel at End of Wall

R602.10.2.2 Locations of braced wall panels. A braced wall

panel shall begin within 10 feet from each end of a braced

wall line as determined in Section R602.10.1.1. The distance

between adjacent edges of braced wall panels along a braced

wall line shall be no greater than 20 feet as shown in Figure

R602.10.2.2.

BWP Spacing and End Distance

Mixing Bracing Amounts

Mixing of bracing method shall be permitted as

follows:

1. Mixing bracing methods from story to story is permitted.

2. Mixing bracing methods from braced wall line to braced wall

line within a story is permitted, except that continuous

sheathing methods shall conform to the additional

requirements of Sections R602.10.4 and R602.10.5.

3. Mixing bracing methods within a braced wall line is permitted

only in Seismic Design Categories A and B, and detached

dwellings in Seismic Design Category C. The length of

required bracing for the braced wall line with mixed

sheathing types shall have the higher bracing length

requirement, in accordance with Tables R602.10.1.2(1) and

R602.10.1.2(2), of all types of bracing used.

Blocking of Horizontal Joints

R602.10.8 Blocking

required at all horizontal

joints in BWPs

– Blocking may be omitted

for WSP, SFB, GB, PBS,

HPS when bracing

amount is doubled

– GB installed horizontally

does not require blocking

R301.3 Story height.

R301.3 Story height. Buildings constructed in

accordance with these provisions shall be limited

to story heights of not more than the following:

1. For wood wall framing, the laterally unsupported

bearing wall stud height permitted by Table

R602.3(5) plus a height of floor framing not to

exceed 16 inches.

Stud Table

R301.3 Story height.

Exception: For wood framed wall buildings with

bracing in accordance with Tables R602.10.1.2(1)

and R602.10.1.2(2), the wall stud clear height

used to determine the maximum permitted story

height may be increased to 12 feet without

requiring an engineered design for the building

wind and seismic force resisting systems provided

that the length of bracing required by Table

R602.10.1.2(1) is increased by multiplying by a

factor of 1.10 and the length of bracing required by

Table R602.10.1.2(2) is increased by multiplying

by a factor of 1.20. Wall studs are still subject to

the requirements of this section.

Construction Issues

No Reduction if: – < 1/16” in dry

conditions

– Not more than 20% around perimeter > 1/16” up to 1/8”

– Actual panel thickness less overdriving amount ≥ required panel thickness (i.e. 7/16” actual w/ 1/8” overdriven = 5/16” net thickness

Overdriven Fasteners (APA TT-012)

Construction Issues

If more than 20% around perimeter are overdriven by 1/16” or if ANY are overdriven by 1/8”, additional fasteners shall be driven to maintain the required shear capacity.

Install one additional fastener for every two fasteners that are overdriven

Overdriven Fasteners (APA TT-012)

Fastener Location Fasteners must be located a minimum of

3/8” from the edge of the panel

Construction Issues

Connections

Where joists are perpendicular to the braced wall lines above, blocking shall be provided under and in line with the braced wall panels.

Where joists are perpendicular to braced wall lines below, blocking shall be provided over and in line with the braced wall panels.

Where joists are parallel to braced wall lines above or below, a rim joist or other parallel framing member shall be provided at the wall to permit fastening per Table R602.3(1).

Connections

Braced wall line sole plates shall be fastened to the floor framing and top plates shall be connected to the framing above in accordance with Table R602.3(1).

Sills shall be fastened to the foundation or slab in accordance with Sections R403.1.6 and R602.11.

Connections

R602.10.6 BWP connections

– Table R602.3(1): 8d Box Nails 6” O.C. rim

board/blocking to top plate below

– Joist, full height blocking, or other framing

member above and below BWPs

Connections

Rim joist to top plate, toe nail

8d (2-1/2″×0.113″) at 6″ o.c.

Sole plate to joist or blocking

at braced wall panels

3-16d (3½”×0.135”) at 16” o.c.

Connections

2. Where joists are parallel to a braced wall

panel above or below, a rim joist, end joist

or other parallel framing member shall be

provided directly above and below the

braced wall panel in accordance with

Figure R602.10.6(2). Where a parallel

framing member cannot be located directly

above and below the panel, full-depth

blocking at 16 inch (406 mm) spacing shall

be provided between the parallel framing

members to each side of the braced wall

panel in accordance with Figure

R602.10.6(2). Fastening of blocking and

wall plates shall be in accordance with

Table R602.3(1) and Figure R602.10.6(2).

Connections

3. Connections of braced wall panels

to concrete or masonry shall be in

accordance with Section R403.1.6.

Miscellaneous Bracing Provisions

Figure R602.10.6(1) Perpendicular Framing


Figure R602.10.6(2) Parallel Framing

R403.1.6 Foundation anchorage.

Sill plates and walls supported directly on

continuous foundations shall be anchored

to the foundation in accordance with this

section.

Wood sole plates at all exterior walls on

monolithic slabs, wood sole plates of

braced wall panels at building interiors on

monolithic slabs and all wood sill plates

shall be anchored to the foundation with

anchor bolts spaced a maximum of 6 feet

on center.

R403.1.6 Foundation anchorage.

Bolts shall be at least ½ inch in diameter and

shall extend a minimum of 7 inches into

concrete or grouted cells of concrete masonry

units.

A nut and washer shall be tightened on each

anchor bolt.

IRC R403.1.6 Foundation Anchorage

There shall be a minimum of two bolts per

plate section with one bolt located not

more than 12 inches or less than seven

bolt diameters from each end of the plate

section.

Interior bearing wall sole

plates on monolithic slab

foundation that are not

part of a braced wall panel

shall be positively anchored

with approved fasteners.

Exceptions:

1. Foundation anchorage, spaced as required to provide equivalent anchorage to 1/2-inch-diameter anchor bolts.


Exceptions:

1. Foundation anchorage, spaced as required to provide equivalent anchorage to 1/2-inch-diameter anchor bolts.

2. Walls 24 inches total length or shorter connecting offset braced wall panels shall be anchored to the foundation with a minimum of one anchor bolt located in the center third of the plate section and shall be attached to adjacent braced wall panels per Figure R602.10.5 at corners.

3. Walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels shall be permitted to be connected to the foundation without anchor bolts. The wall shall be attached to adjacent braced wall panels per Figure R602.10.5 at corners.


Miscellaneous Bracing

Provisions


R106.1.1 Building official may require

that construction documents include

– Braced Wall Lines

– Braced Wall Panel location and length

– Bracing Method

– Foundation Requirements

Uplift at braced wall panels

R602.10.1.2.1 Braced wall panel uplift load path. Braced wall panels located at exterior walls that support roof rafters or trusses (including stories below top story) shall have the framing members connected in accordance with one of the following:

1. Fastening in accordance with Table R602.3(1) where:

1.1 The basic wind speed does not exceed 90 mph, the wind exposure category is B, the roof pitch is 5:12 or greater, and the roof span is 32 feet or less, or

1.2 The net uplift value at the top of a wall does not exceed 100 plf. The net uplift value shall be determined in accordance with Section R802.11 and shall be permitted to be reduced by 60 plf for each full wall above.

2. Where the net uplift value at the top of a wall exceeds 100 plf, installing approved uplift framing connectors to provide a continuous load path from the top of the wall to the foundation. The net uplift value shall be as determined in Item 1.2 above.

3. Bracing and fasteners designed in accordance with accepted engineering practice to resist combined uplift and shear forces.

Uplift at BWP’s

R602.10.1.2.1 Uplift load path required

– Approved uplift framing connectors

required at top and bottom of studs at

braced wall panels when net uplift from

R802.11 exceeds 100 plf

These loads are for framing 24” o.c.

Divide by two for plf


R602.10.6.2 BWP connections to roof

– Top of rafter/truss to top of top plate ≤ 9¼”:

no additional requirements (low seismic)

– ≤ 14¼”: Figure R602.10.6.2(1)

– ≤ 48”: Figures R602.10.6.2(2) or

R602.10.6.2(3)


R602.10.7 BWP support

1. BWP on cantilevered floor joists

2. BWP on elevated post or pier foundations

3. BWP on masonry stem walls

a. Length ≤ 48”: reinforced per Figure R602.10.7

b. ABW and PFH not permitted on masonry

HEEEEERE’S

BILLY!

Another Challenge

About That Great Room…

Topics:

– Framing for great room walls

– Framing for 2 story entry area

walls

– Bracing in these areas

– Alternative solutions

Great Room & Tall Wall Areas


IRC R602.10

– Bracing amounts based on 10’ wall heights

IRC R301.3 Exception

– Can increase wall height to 12’ without

engineered design provided length of bracing

in Table R602.10.1 is increased by a factor of

1.2

IRC Table R602.10.6

– alternate wall panels up to 12’ height (SDC A-

C only)

IRC Table R602.3(5)

– Limits bearing wall stud height to 10’


How do I build a great room wall?

IRC 2006 R602.3.1

– Studs more than 10’ in height in accordance

with Table R602.3.1

– Allows for certain size & grade stud heights up

to 24’

IRC 2006 R602.8 -- Fireblocking

– Requires horizontal blocking at intervals not

exceeding 10 feet

IRC 2006 R602.10 – Bracing still applies!

– Is it 1 story or 2?

– What type of braced wall panels do I use?

<25’

A Proprietary Solution: – Stacked Prefabricated Shearwall applications

– Available now from several manufacturers

– Based on SDC, wind speed, & foundation type

– Looks at values of single story and 1st of 2 stories




2 BRACED WALL LINES


BASIC WIND SPEED

STORY LOCATION


(FT)

METHOD LIB

f,h

METHOD GB (DOUBLE

SIDED)g


i

CONT. SHEATHING

≤ 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



Total bracing = 2 X 10.5 = 21’



2 BRACED WALL LINES


BASIC WIND SPEED

STORY LOCATION


(FT)

METHOD LIB

f,h

METHOD GB (DOUBLE

SIDED)g


i

CONT. SHEATHING

≤ 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



Total bracing = 3 X 5.5 = 16.5’ (less than 21’ required)

f. Bracing lengths are based on the application of gypsum board finish (or equivalent) applied to the inside face of a braced wall panel. When gypsum board finish (or equivalent) is not applied to the inside face of braced wall panels, the tabulated lengths shall be multiplied by the appropriate factor from the following table:

Bracing Method Adjustment Factor

Method LIB 1.8

Methods DWB, WSP, SFB, PBS, PCP, HPS 1.4

i. Required bracing length for Methods DWB, WSP, SFB, PBS, PCP and HPS in braced wall lines located in one-story buildings and in the top story of two or three story buildings shall be permitted to be multiplied by 0.80 when an approved hold-down device with a minimum uplift design value of 800 pounds is fastened to the end studs of each braced wall panel in the braced wall line and to the foundation or framing below.

DTT2Z or FSC

Seismic Bracing

SOIL CLASS Da

WALL HEIGHT = 10 FT 10 PSF FLOOR DEAD LOAD

15 PSF ROOF/CEILING DEAD LOAD BRACED WALL LINE SPACING ≤ 25 FT


SEISMIC DESIGN

CATEGORY (SDC)

STORY LOCATION

BRACED WALL LINE

LENGTH METHOD LIB

METHODS

DWB, SFB, GB, PBS, PCP, HPS

METHOD WSP

CONT. SHEATHING

SDC A and B, and Detached Dwellings in C

Exempt from Seismic Requirements Use Table R602.10.1.2(1) for bracing requirements

SOIL CLASS Da

WALL HEIGHT = 10 FT 10 PSF FLOOR DEAD LOAD

15 PSF ROOF/CEILING DEAD LOAD

1 BWL BWLBRACED WALL LINE

SPACING ≤ 25 FT


SEISMIC DESIGN

CATEGORY (SDC)

STORY LOCATION

BRACED WALL LINE

LENGTH

METHOD LIB

METHODS

DWB, SFB, GB, PBS, PCP,

HPS

METHOD WSP

CONT. SHEATHING

10 NP 3.0 2.0 1.7

20 NP 6.0 4.0 3.4

30 NP 9.0 6.0 5.1

40 NP 12.0 8.0 6.8

50 NP 15.0 10.0 8.5

10 NP 6.0 4.5 3.8

20 NP 12.0 9.0 7.7

30 NP 18.0 13.5 11.5

40 NP 24.0 18.0 15.3

50 NP 30.0 22.5 19.1

10 NP 8.5 6.0 5.1

20 NP 17.0 12.0 10.2

30 NP 25.5 18.0 15.3

40 NP 34.0 24.0 20.4

SDC D0 or D1

50 NP 42.5 30.0 25.5

Questions?

Thank you!

Braced Wall Amount and Location Example:

Single Story, Category A or B, 100 mph or less – Wall Length = 50’

– Required Braced Wall Length = (50’)x(16%) = 8’

– Available Wall Length = 12’-4”+12’-4”+4’; Use two 12’-4” walls

Check O.C. Spacing; 20’ OK – Must begin no more than 12’6” from end of wall line; OK

R602.10.1 Braced Wall Lines

30’ front wall:

A, B or C - 30ft(.16)= 4.8 ft

D1 - 30ft(.20)= 6 ft

D2 - 30ft(.25)= 7.5 ft

32"

32" 48" Req'd (Use 60" to elminate need for 3 panels)

48"

48"

30'-0"

9'-0"

20'-0"

9'-0"

6

12

21'-4" 26'-0"

elminate

panels)

1800 lb. Holdown Req'd (3000 lb for 2-story)

21’-4” garage front:

A, B, or C - (21.33)(.16) = 3.4 ft

D1 – (21.33)(.20)= 4.27 ft

D2 – (21.33)(.25)= 5.33 ft

Braced Wall Example

32"

32" 48"

48"

30'-0"

9'-0"

20'-0"

9'-0"

6

12

21'-4" 25'-0"

elminate

panels)

1800 lb. Holdown Req'd (3000 lb for 2-story)

Braced Wall Example

5’

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