shear walls section 3. typical shear wall even distribution of shear walls even distribution of...
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Shear WallsShear WallsShear WallsShear Walls
Section 3Section 3
Typical Shear WallTypical Shear WallTypical Shear WallTypical Shear Wall
Even Distributionof Shear Walls
Even Distributionof Shear Walls
Location of Shear Location of Shear WallsWalls
Location of Shear Location of Shear WallsWalls
Create box structureCreate box structure
Equal length & Equal length & symmetricalsymmetrical
Create box structureCreate box structure
Equal length & Equal length & symmetricalsymmetrical
Break inBreak inLoad PathLoad Path
InteriorInteriorPartitionPartition
InteriorInteriorShear WallShear Wall
Continuous Load PathContinuous Load PathFloor Must Support Shear WallFloor Must Support Shear Wall
Cripple WallCripple Wall
ExteriorExteriorShear WallShear Wall
Vertical Offset of Vertical Offset of Shear WallShear Wall
Vertical Offset of Vertical Offset of Shear WallShear Wall
Shear Shear Wall OverWall Over
Floor Floor BeamBeam
Shear Shear Wall OverWall Over
Floor Floor BeamBeam
Horizontal Shear Horizontal Shear ForcesForces
Horizontal Shear Horizontal Shear ForcesForces
Uplift Uplift Forces OnForces On
Shear Shear WallWall
Uplift Uplift Forces OnForces On
Shear Shear WallWall
STIFFNESSControl Sidesway
STIFFNESSControl SideswayEarthquake ForceEarthquake Force
ConnectionFor Uplift
Resistance
ConnectionFor Uplift
ResistanceConnectionFor SlidingResistance
ConnectionFor SlidingResistance
STRENGTHSTRENGTH
ResistShear
Two Functions of a Two Functions of a Shear WallShear Wall
Two Functions of a Two Functions of a Shear WallShear Wall
What Provides Shear What Provides Shear Wall Strength?Wall Strength?
What Provides Shear What Provides Shear Wall Strength?Wall Strength?
LumberLumber
SheathinSheathingg
FastenerFastenerss
LumberLumberStrengtStrengt
hhFailureFailure
LumberLumberStrengtStrengt
hhFailureFailure
Sheathing Strength Sheathing Strength FailureFailure
Sheathing Strength Sheathing Strength FailureFailure
FastenFastenerer
StrengtStrengthh
FailureFailure
FastenFastenerer
StrengtStrengthh
FailureFailure
Combining Different Combining Different Material StrengthsMaterial Strengths
Combining Different Combining Different Material StrengthsMaterial Strengths
Different sheathing materials Different sheathing materials DO NOT combine strengthDO NOT combine strength
Sheathing materials reach Sheathing materials reach ultimate strength at different ultimate strength at different wall displacementswall displacements
Different MaximumDisplacements
Wall Displacement
Sheathing Material Sheathing Material StrengthsStrengths
Sheathing Material Sheathing Material StrengthsStrengths
Earthquake ForceEarthquake Force
Resisting Forcefrom ConnectionResisting Forcefrom Connection
End Studin TensionEnd Studin Tension
End Stud inCompression
End Stud inCompression
C T
C T
Earthquake ForceEarthquake Force
Most Important Most Important FactorsFactors
Most Important Most Important FactorsFactors
ARESTIFFER
THAN
ARESTIFFER
THANLong Short WallsLong Short Walls
TallNarrowWalls
TallNarrowWalls
Allowable Aspect Allowable Aspect RatiosRatios
Allowable Aspect Allowable Aspect RatiosRatios
Northridge EarthquakeNorthridge EarthquakeShowed Us:Showed Us:
Northridge EarthquakeNorthridge EarthquakeShowed Us:Showed Us:
Most materials did NOT Most materials did NOT do as well as predicteddo as well as predicted
More material and wider More material and wider walls neededwalls needed
Reduced Code ValuesReduced Code ValuesReduced Code ValuesReduced Code Values
Drywall Drywall FailureFailureDrywall Drywall FailureFailure
Stucco FailureStucco FailureStucco FailureStucco Failure
NarrowNarrowPanelPanel
FailureFailure
NarrowNarrowPanelPanel
FailureFailure
Successful Plywood Successful Plywood CoverageCoverage
Successful Plywood Successful Plywood CoverageCoverage
Wood Structural Wood Structural Panel Shear WallsPanel Shear WallsWood Structural Wood Structural
Panel Shear WallsPanel Shear Walls
Lumber typeLumber type
Lumber sizeLumber size
Condition of existing Condition of existing woodwood
Douglas Fir-LarchDouglas Fir-LarchDouglas Fir-LarchDouglas Fir-Larch Hem FirHem FirHem FirHem Fir
StrongerStrongerStrongerStronger WeakerWeakerWeakerWeaker
Effect Of Lumber Species Effect Of Lumber Species On StrengthOn Strength
Effect Of Lumber Species Effect Of Lumber Species On StrengthOn Strength
Structural 1Structural 1
Allowable Shears (lbs/ft)Based on Lumber SpeciesAllowable Shears (lbs/ft)Based on Lumber Species
RedwoodOpen GrainRedwood
Open GrainHem-
FirDouglasFir-Larch
Nail Spacin
g at Panel Edges
Common
Nail Sizes
Wood Structural Panel
ThicknessPanel Grade
15/32 inStructural 1 8d 4 430 355 280280
15/32 inStructural 1 8d 3 550 450 360360
15/32 in15/32 in 10d10d 33 665665 545545 430430
Use Proper Size StudUse Proper Size StudUse Proper Size StudUse Proper Size Stud
Framing members split at Framing members split at ultimate loads when sheathing ultimate loads when sheathing nails are closely spacednails are closely spaced
Shear Walls: 17% stronger Shear Walls: 17% stronger when 3” framing used when 3” framing used throughoutthroughout
2” 2” AdjoininAdjoining Studg Stud
2” 2” AdjoininAdjoining Studg Stud
Install Proper Size Install Proper Size BlockingBlocking
Install Proper Size Install Proper Size BlockingBlocking
Fasten all edges to framing Fasten all edges to framing members or blockingmembers or blocking
Provide blocking if panel Provide blocking if panel members are unsupported members are unsupported between framing membersbetween framing members
Cripple Wall BlockingCripple Wall BlockingCripple Wall BlockingCripple Wall Blocking
3” Flat Blocking3” Flat Blocking3” Flat Blocking3” Flat Blocking
ReinforcReinforced ed
Window Window Opening Opening in Shear in Shear
WallWall
ReinforcReinforced ed
Window Window Opening Opening in Shear in Shear
WallWall
Blocking For Blocking For Opening Opening
ReinforcemeReinforcementnt
Blocking For Blocking For Opening Opening
ReinforcemeReinforcementnt
How is the Length ofHow is the Length ofShear Wall Measured?Shear Wall Measured?How is the Length ofHow is the Length of
Shear Wall Measured?Shear Wall Measured?
Horizontally along sheathing Horizontally along sheathing between wall ends with hold-between wall ends with hold-downsdowns
NOTNOT length of plywood length of plywood
ISIS measured by hold-down measured by hold-down locationlocation
What’s What’s Wrong?Wrong?What’s What’s Wrong?Wrong?
Too close to Too close to end wall; end wall; countersunkcountersunk
Too close to Too close to end wall; end wall; countersunkcountersunk
What’s What’s Wrong?Wrong?What’s What’s Wrong?Wrong?
Too far Too far from shear from shear wall endwall end
Too far Too far from shear from shear wall endwall end
Acceptable Hold-Down Acceptable Hold-Down LocationLocation
Acceptable Hold-Down Acceptable Hold-Down LocationLocation
Lumber GradeLumber GradeLumber GradeLumber Grade
Effect of Lumber Effect of Lumber Grade onGrade on
Hold-Down CapacityHold-Down Capacity
Effect of Lumber Effect of Lumber Grade onGrade on
Hold-Down CapacityHold-Down Capacity
Penetration Through Penetration Through Shear WallShear Wall
Penetration Through Penetration Through Shear WallShear Wall
Wood DecayWood DecayWood DecayWood Decay
Termite Termite DamageDamageTermite Termite DamageDamage
Crawl Space Crawl Space VentilationVentilation
Crawl Space Crawl Space VentilationVentilation
Installing the Installing the SheathingSheathing
Installing the Installing the SheathingSheathing
Use specified wood Use specified wood structural panelstructural panel
OSBOSB
PlywoodPlywood
Construction of Construction of Oriented Strand Board Oriented Strand Board
PanelPanel
Construction of Construction of Oriented Strand Board Oriented Strand Board
PanelPanel
Construction of Construction of PlywoodPlywood
Construction of Construction of PlywoodPlywood
3 ply3 layer panel3 ply3 layer panel
4 ply3 layer panel4 ply3 layer panel
5 ply5 layer panel5 ply5 layer panel
Minimum Minimum Recommended Recommended
ThicknessThickness
Minimum Minimum Recommended Recommended
ThicknessThickness 15/32”15/32”
Both 4-ply and 5-plyBoth 4-ply and 5-ply
More plies More plies stronger stronger sheathingsheathing
Use Correct Panel Use Correct Panel GradeGrade
Use Correct Panel Use Correct Panel GradeGrade
Sheathing OrientationSheathing OrientationSheathing OrientationSheathing Orientation
2” studvertical orhorizontal
3” stud
3” block
nail edges
Use proper size panelUse proper size panel 2:1 aspect ratio2:1 aspect ratio 4’ x 8’ panel minimum4’ x 8’ panel minimum
Mark stud locations on panelsMark stud locations on panels Avoid improper fasteningAvoid improper fastening
Maintain fire resistive and Maintain fire resistive and sound-rated constructionsound-rated construction Don’t change anything!Don’t change anything!
Cripple Wall Cripple Wall VentilationVentilation
Cripple Wall Cripple Wall VentilationVentilation
Shear WallShear WallFastenersFasteners
Shear WallShear WallFastenersFasteners
Use Common NailsUse Common NailsUse Common NailsUse Common Nails
Use ProperUse Proper
Nail LengthNail Lengthandand
Head SizeHead Size
Use ProperUse Proper
Nail LengthNail Lengthandand
Head SizeHead Size
Performance Performance Losses for Nail Losses for Nail SubstitutionsSubstitutions
Performance Performance Losses for Nail Losses for Nail SubstitutionsSubstitutions
Nail Gun With Flush Nail Gun With Flush AttachmentAttachment
Nail Gun With Flush Nail Gun With Flush AttachmentAttachment
Round-Round-Head NailsHead Nails(P-Nails)(P-Nails)
Round-Round-Head NailsHead Nails(P-Nails)(P-Nails)
ModifiedModifiedRound-Round-
Head Nails Head Nails (P-Nails)(P-Nails)
ModifiedModifiedRound-Round-
Head Nails Head Nails (P-Nails)(P-Nails)
Clipped Nail Clipped Nail HeadHead
Clipped Nail Clipped Nail HeadHead
Smaller nail head Smaller nail head areas areas smaller smaller
shear wall strengthsshear wall strengths
Smaller nail head Smaller nail head areas areas smaller smaller
shear wall strengthsshear wall strengths
1994 1994 UBC:UBC:1994 1994 UBC:UBC:
Nail should “not fracture the Nail should “not fracture the surface of the sheathing”surface of the sheathing”Nail should “not fracture the Nail should “not fracture the surface of the sheathing”surface of the sheathing”
1997 1997 UBC:UBC:1997 1997 UBC:UBC:
The “head or crown of the The “head or crown of the nail is flush with the surface nail is flush with the surface of the sheathing”of the sheathing”
The “head or crown of the The “head or crown of the nail is flush with the surface nail is flush with the surface of the sheathing”of the sheathing”
Overdriven nails reduce Overdriven nails reduce shear wall strengthshear wall strength
Overdriven nails reduce Overdriven nails reduce shear wall strengthshear wall strength
OverdrivOverdriven Nailsen NailsOverdrivOverdriven Nailsen Nails
Improper Improper Edge Edge
DistanceDistance
Improper Improper Edge Edge
DistanceDistance
ImportantImportantImportantImportant
Install nails flush to sheathingInstall nails flush to sheathing
Maintain proper sheathing edge Maintain proper sheathing edge distancedistance
Check for splittingCheck for splitting
Remove improperly installed nailsRemove improperly installed nails
Provide proper edge nailingProvide proper edge nailing
OOPS!OOPS!OOPS!OOPS!
How to Nail a Shear How to Nail a Shear WallWall
How to Nail a Shear How to Nail a Shear WallWall
Edge nailEdge nail:: hold-down stud(s)hold-down stud(s) upper top plateupper top plate sill or sole platesill or sole plate blocking for individual panel edgesblocking for individual panel edges blocking for opening reinforcementblocking for opening reinforcement
Field nailField nail the studs between the panel the studs between the panel edgesedges