2012 irc wall bracing provisions - ohiobbseducation.com 8 bbs2015-464.pdf · 2012 irc wall bracing...

2012 IRC Wall Bracing Provisions

CONNECTIONS CRIPPLE WALLS FOUNDATION

Module 8

2012 IRC Wall Bracing 2

Objectives

• Upon completion of this module, you will be better able to:

• Describe connection of braced wall panels

• Describe cripple walls

• Identify foundations


Item Building Element Number and Type

of Fastener

Spacing of

Fasteners

7 Built-up studs-face nail 10d (3" × 0.128") 24" o.c.

8

Abutting studs at

intersecting wall corners,

face nail

16d (3 ½” x 0.135”) 12" o.c.

12 Double studs, face nail 10d (3" × 0.128") 24" o.c.

13 Double top plates, face nail 10d (3" × 0.128") 24" o.c.


Bracing: Connections BWP sole plates and top plates connections per Table R602.3(1)

Excerpt from Table R602.3(1) Items 7, 8, 12, 13

Item Building Element Number and Type of

Fastener

Spacing of

Fastener

14

Double top plates,

minimum 24-inch offset of

end joints, face nail in

lapped area

8-16d (31/2″ × 0.135″) --

16 Sole plate to joist or

blocking at braced wall

panels

3-16d (31/2″ × 0.135″) 16″ oc


Bracing: Connections BWP sole plates and top plates connections per Table R602.3(1)

Excerpt from Table R602.3(1) Items 14 and 16


Bracing: 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)

3.7

BWP BWP BWP


7

BWP Perpendicular to Framing

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




Where joists are parallel to BWPs above or below… where a parallel framing 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)


9

BWP Parallel to Framing

Figure R602.10.8(2) & Table R602.3(1)

2012 IRC Wall Bracing

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 Item 1 and

Figure R602.10.8.2(1)

SDC D0, D1, D2

Wind > 100 mph 15.25" or less

Per R602.10.8.2 Item 2 and Figure

R602.10.8.2(1)

All SDCs

Wind < 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



Figure 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″ from

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).




For all Seismic Design

Categories and wind

speeds, where

• Distance > 15.25″ from 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)



Figure R602.10.8.2(3)

Roof Trusses per R802.10

Bracing


Roof Connections

Section R802.11

2009 IRC - requires roof assemblies with more than 20 psf roof uplift pressure to use connectors having a minimum capacity equal to Table R802.11. Use Table R301.2(2) to determine uplift (-) value

2012 IRC Wall Bracing 14 R802.11

2009 IRC

Component and cladding loads above 20 psf require a connector.

For shallow roofs, that only occurs in regions with winds more than 100 mph


Roof Connections

Roof Connections

Zones 2 and 3 are at the edges of roofs


Roof Connections

Section R802.11

2012 IRC - requires roof assemblies with uplift greater than 200 lbs to have rafters or trusses tied to walls with connectors having a minimum capacity equal to Table R802.11

2012 IRC Wall Bracing 17 R802.11

2012 IRC

Use of Table R301.2(2) is not needed

Under 200 lbs, 3 toenails are OK

Above 200 lbs, a manufactured connector is required.

2012 IRC Wall Bracing 18 Table R802.11

Roof Connections

For loads above 200 psf


CRIPPLE WALLS



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 Walls

Cripple Wall

A 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 Walls


Cripple Wall Supporting One Story

Bracing Length from

Tables R602.10.3(1) or (3)

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

Bracing Length from

Tables R602.10.3(1) or (3)

for Roof only

1.15 x (Roof + 1 Floor BP Length)

Bracing Length from

Tables R602.10.3(1) or (3)

for Roof + 1 Floor

14' BWP edge to edge

Cripple Wall Supporting Two Stories

Redesignated as a Three Story

20' BWP edge to edge

Bracing Length from

Tables R602.10.3(1) or (3)

for Roof only

BP length for Roof + 2 Floors

Bracing Length from

Tables R602.10.3(1) or (3)

for Roof + 1 Floor

or

Cripple Walls

2012 IRC Wall Bracing 23 R602.10.11

Seismic Design Categories A-D1

2012 IRC Wall Bracing Wind 24

Cripple Walls

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

Stacked framing not permitted

Cripple Walls


FOUNDATION


Bracing: Foundation


Soil friction Lateral bearing capacity

Weight of the structure and footing Bearing capacity of soil

Weight of soil

Sliding Resisted by soil friction and lateral bearing capacity of soil.

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

Bracing: Foundation


7"

1' 0"

6"

1' 0"

6" 7"

W W

T

P

3-1/2"

R403.1.1

Slab on Grade Raised Floor

Bracing: Foundation


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

Bracing: Foundation


Footings: Anchor bolt length

• 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

Bracing: Foundation


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 masonry

walls 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)

Bracing: Foundation


3"

#4 bars at top & bottom

For footings supporting an ABW or PFH panel

R403.1.3.2

Wall Bracing Section Requirements

Bracing: Foundation


Narrow Masonry Wall Requirements Only required for walls less

than 48" long.

Bracing: Foundation - Wood


Summary

This module covered: • Connection of braced wall panels

– Table R602.3(1) contains a number of requirements for the fastening of wall elements.

– When braced wall panels are parallel to joists above or below and the joists are not aligned with the braced wall panels, blocking at 16 inches on center is required between the joists.

• Cripple Walls – situated at the bottom of the first story – main code provisions for cripple walls are in Section R602.9.

• Foundations – In the case of the RCO, foundations are focused on footings – OBC Sections R403 and R602.10 do not directly reference the

foundation and basement wall section of Chapter 4.


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© International Code Council 2014

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