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Wood Framed Renee Strand, P.E.Senior EngineerWood Framed
Tall Walls
Senior Engineer iLevel® by Weyerhaeuser Tall Walls
July 2010
yNR
AIA CourseAIA CourseAIA CourseAIA CourseWoodWorks is a Registered Provider with the American Institute of A hit t C ti i Ed ti S t C dit d Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are
il bl available on request.
This program is registered with the AIA/CES for continuing p g g gprofessional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentationaddressed at the conclusion of this presentation.
Presentation ObjectivesPresentation ObjectivesTall Wall Applications
Presentation ObjectivesPresentation Objectivespp
ChallengesThermal PerformanceThermal PerformanceProductsD i C id tiDesign ConsiderationsFraming DetailsFire AssembliesInnovative Solutions
Wood Framed Tall Wall ApplicationsWood Framed Tall Wall ApplicationsWood Framed Tall Wall ApplicationsWood Framed Tall Wall Applications
Residential ConstructionFoyersGreat Rooms
Wood Framed Tall Wall ApplicationsWood Framed Tall Wall ApplicationsWood Framed Tall Wall ApplicationsWood Framed Tall Wall ApplicationsLight-Framed Commercial W d C t tiWood ConstructionSchoolsCh hChurchesRetailMulti-Family
Challenges Associated with Tall WallsChallenges Associated with Tall WallsChallenges Associated with Tall WallsChallenges Associated with Tall WallsLarge OpeningsMaintain in-plane shear pathMaintaining Height to Width Ratio of Shear Walls
O f Pl D fl iOut-of-Plane DeflectionProtect finishes / keep building envelope in tacked
C nstr cti nConstructionHinge pointsConnectionsConnectionsBracing
Quality of materialQuality of material
Large OpeningsLarge OpeningsLarge OpeningsLarge OpeningsIn-Plane Shear TransferMaximum Shear Wall Dimension Ratios – Table 2305.3.4 (2006 IBC)
Wood Structural Panels3 5 1 f h h
h
3.5:1 for other than seismic2:1 for seismic3.5:1 for seismic if allowable
wshear multiplied by 2w/h
Large OpeningsLarge OpeningsLarge OpeningsLarge OpeningsIn-Plane Shear Transfer Pre-fabricated Shear Walls
Allowable In-Plane Shear loadsShear loads
• 550 lbs to 1460 lbs seismic control
• 605 lbs to 2445 lbs wind control
OutOut--ofof--Plane Deflection LimitsPlane Deflection LimitsExcessive Deflection
OutOut--ofof--Plane Deflection LimitsPlane Deflection Limits
Walls don’t feel stiffPerformance issues
Moisture intrusionExterior/Interior finish cracks and pops
OutOut--ofof--Plane Deflection LimitsPlane Deflection Limits
IBC Table 1604.3
OutOut--ofof--Plane Deflection LimitsPlane Deflection Limits
Flexible Finishes: H/120 (2009 IBC – H/180)Brittle Finishes: H/240Brittle Finishes: H/240The wind load is permitted to be taken as 0.70 times the “component and cladding” loads for the purpose p g p pof determining deflection limits
IBC Section 2403.3IBC Section 2403.3Mullions: L/175 up to ¾"
2006/2009 IRC Table R301 7 2006/2009 IRC Table R301.7 Plaster/Stucco Surfaces: H/360
ConstructionConstructionConstructionConstructionNot Straight
Bowing, twisting and warpingof solid-sawn lumber
Limited Material Lengthsg“Hinge Point” creates a structural weakness in the wall
ConstructionConstructionConstructionConstruction
WINDWIND
WINDWIND
Thermal PerformanceThermal PerformanceThermal PerformanceThermal Performance
Source: The Thermal Performance of Light-Frame Assemblies, Canadian Wood Council
Thermal PerformanceThermal PerformanceThermal PerformanceThermal Performance
Source: The Thermal Performance of Light-Frame Assemblies, Canadian Wood Council
ProductsProductsProductsProducts
Dimension LumberDimension LumberStuds, Headers, Built-up ColumnsS lid S Solid Sawn
2x4 to 2x14 (20ft to 26ft)
Fi J i t dFinger-JointedVertical Stud Use Only (12ft)
2x3 to 2x6
Structural Finger Joint (32ft to 40ft)HRA or Non- HRA
(Heat Resistant Adhesive)( )2x3 to 2x12
ProductsProductsProductsProductsEngineered Lumber ProductsStuds
Laminated Veneer Lumber (LVL)Laminated Strand Lumber (LSL) Glue Laminated Lumber
H d d C l Headers and Columns Structural Composite Lumber (SCL)
LSL LVL Glu Lam Parallel Strand Lumber (PSL)LSL, LVL, Glu-Lam, Parallel Strand Lumber (PSL)
Glue Laminated Lumber
ProductsProductsProductsProductsEngineered Lumber Products
Code Evaluation ReportsAC202 – Acceptance Criteria for Wood-Based Studs6 0 Evidence Submitted6.0 Evidence SubmittedEx.: 6.2 Data in accordance with the ICC-ES Acceptance Criteria for Wood-based Studs (AC202), dated June 2009dated June 2009.
Design ConsiderationsDesign Considerationsgg
Combined Loads Vertical Load
Vertical LoadRoof/Snow and dead
L l L dLateral LoadWind load (⊥ to wall plane)Wind and Seismic (// to wall plane) P
ress
ure
( p )
Deflection
orm
Win
d P
Deflection
Uni
fo
n
Vertical Load
Stud or ColumnUniform Wind Pressure
Top View of Wall Header
Design ConsiderationsDesign ConsiderationsDesign ConsiderationsDesign ConsiderationsBuckling Height Limits
Every column has a height limit to prevent bucklingMax height = 50d (d= depth in inches)
1½”: 8’ height limit 1½”: 8’ height limit 3½” (2x4) Max Height: 14’3½” (2x4) Max Height: 14’5½” (2 6) M H i ht 22’5½” (2 6) M H i ht 22’ 6”6”1½ : 8 height limit 1½ : 8 height limit
between blocking…between blocking…5½” (2x6) Max Height: 22’5½” (2x6) Max Height: 22’--6”6”7¼” (2x8) Max Height: 30’7¼” (2x8) Max Height: 30’
Stud or column in a sheathed Stud or column in a sheathedStud or column in a sheathed wall is braced against buckling in this direction.
Stud or column in a sheathed wall is not braced against buckling in this direction.
Design ConsiderationsDesign ConsiderationsDesign ConsiderationsDesign ConsiderationsNational Design Specification (NDS)g p ( )Eqn 15.4-1 0
Eqn 3.7-1
Eqn 15.3-1 – multiple Cp by Kf for built-up q p p y f pcolumns
Design ConsiderationsDesign Considerations
NDS t ti
Design ConsiderationsDesign Considerations
NDS notationsCP
c = 0.9 for SCL and GLBc = 0.8 for sawn lumberc 0.8 for sawn lumber
Design ConsiderationsDesign Considerations
NDS t ti
Design ConsiderationsDesign Considerations
NDS notationsCP
FcE = 0.822 Emin′/(le/d)2
E ′ = E[1-1 645COVe](1 03)/1 66 (D-4)Emin E[1-1.645COVe](1.03)/1.66 (D-4)E = Eapparent
COV 0 25 0 095COVe = 0.25 to 0.095Ke = 0.85 to 1.0 to determine le
Design ConsiderationsDesign ConsiderationsAllowable Design Stresses
Design ConsiderationsDesign Considerations
Design Stresses
DF‐L #2 SP #2 ES11 ES12 LSL 24F LVL PSL
Fb psi 900 1250 1350 19501700 to 2360
24002250 to 2950
29002360 2950
E x 106 psi 1.6 1.6 1.6 1.9 1.3 to 1.6 1.6 1.5 to 2.0 2.0
Fv psi 95 90 200 200400 to 410
190250 to 290
290
Fc// psi 1350 16001350 to 1550
1700 to 2300
1400 to 2175
16502350 to 3200
2900
Design ConsiderationsDesign Considerations
NDS
Design ConsiderationsDesign Considerations
NDS notationse = eccentricity
1/6 of the wall thickness 1/6 w
w
Design ToolsDesign ToolsDesign ToolsDesign Tools Wind LoadsWind LoadsWind LoadsWind Loads
Exposure ‘B’
Exposure ‘C’ Exposure ‘D’
Design ToolsDesign ToolsDesign ToolsDesign Tools Design ToolsDesign ToolsDesign ToolsDesign Tools
Framing DetailsFraming DetailsFraming DetailsFraming Details Framing DetailsFraming Details
Bracing?
Framing DetailsFraming Details
Bracing?
Framing DetailsFraming DetailsFraming DetailsFraming Details Framing DetailsFraming DetailsFraming DetailsFraming Details
Framing DetailsFraming DetailsFraming DetailsFraming Details Framing DetailsFraming DetailsFraming DetailsFraming Details
Framing DetailsFraming DetailsFraming DetailsFraming DetailsNailinggSpacingLateral and withdrawal values
Dependent on specific gravity of productSpecific gravity varies between face and edge
Hold-downsBolt valuesscrews
FireFireFireFireMultiple Resources for Fire-rated assembliesSolid SawnIBCGypsum Association GA-600-2009 Gypsum Association GA 600 2009 www.gypsum.orgAmerican Wood Council Design for Code gAcceptance 3 www.awc.org
Finger-Jointed StudHRA mark required
FireFireFireFireELPCheck manufacturer’s code evaluation report
May be a direct substitute in sawn lumber assembliesMay be reduction to allowable design stressesM d ddi i l i l iMay need additional insulation
FireFireFireFireFire Retardant TreatmentsLSL, LVL, PSL check with the manufacturer
Most don’t allow – voids warranty
Glue-laminated members check with manufacturerNot recommended
LumberAllowed
Design Value Reductions – 0.80 to 0.98Galvanized or stainless steel fasteners – reductions apply – 0.91 to 0.98
Innovative SolutionsInnovative SolutionsInnovative SolutionsInnovative SolutionsTilt-up LSL wall
Innovative Solutions Innovative Solutions I-Joists as wall studs?
Innovative Solutions Innovative Solutions J
AdvantagesReduced capacity for thermal bridgingReduced capacity for thermal bridgingThicker walls / More insulation
DisadvantageDisadvantageNot code evaluatedNon rectangular shapeNon-rectangular shapeSpecial detailing requiredNo load tablesNo load tables
Th k YTh k YThank YouThank You
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