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Wood Framed Tall Wall Applications Light-Framed Commercial Wd C it tWood Construction Schools Ch hChurches Retail Multi-Family Challenges Associated with …
AIA Course WoodWorks is a Registered Provider with the American Institute of A hit t Continuing Architects C ti i Education Ed ti Systems. S t C Credit dit earned d on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available il bl on request.

Wood Framed Tall Walls July 2010

Renee Strand, P.E. Senior Engineer iLevel® by Weyerhaeuser y NR

Presentation Objectives Tall Wall Applications pp Challenges Thermal Performance Products D i C Design Considerations id ti Framing Details Fire Assemblies Innovative Solutions

This pprogram g is registered g with the AIA/CES for continuingg professional 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 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 presentation. presentation

Wood Framed Tall Wall Applications Residential Construction Foyers „ Great Rooms „

Wood Framed Tall Wall Applications Light-Framed Commercial Wood Construction W dC t ti

Challenges Associated with Tall Walls Large Openings Maintain in-plane shear path „ Maintaining Height to Width Ratio of Shear Walls „

Schools „ Churches Ch h „ Retail „ Multi-Family „

O Out-of-Plane f Pl D Deflection fl i „

Protect finishes / keep building envelope in tacked

C nstr cti n Construction Hinge points „ Connections „ Bracing „

Quality of material

Large Openings

Large Openings In-Plane Shear Transfer

In-Plane Shear Transfer „

Maximum Shear Wall Dimension Ratios – Table 2305.3.4 (2006 IBC) „

Wood Structural Panels 33.5:1 5 1 ffor other h than h seismic „ 2:1 for seismic „ 3.5:1 for seismic if allowable shear multiplied by 2w/h





Pre-fabricated Shear Walls

Allowable In-Plane Shear loads • 550 lbs to 1460 lbs seismic control • 605 lbs to 2445 lbs wind control

Out-of Outof--Plane Deflection Limits Excessive Deflection Walls don’t feel stiff „ Performance issues „

Moisture intrusion „ Exterior/Interior finish cracks and pops „

Out-of Outof--Plane Deflection Limits IBC Table 1604.3 Flexible Finishes: H/120 (2009 IBC – H/180) „ Brittle Finishes: H/240 „ The wind load is permitted to be taken as 0.70 times the “component p and cladding” g loads for the purpose p p of determining deflection limits „

IBC Section 2403.3 „

Mullions: L/175 up to ¾"

2006/2009 IRC Table R301.7 R301 7 „


Plaster/Stucco Surfaces: H/360


Not Straight „

Bowing, twisting and warping of solid-sawn lumber


Limited Material Lengths g „

“Hinge Point” creates a structural weakness in the wall WIND

Thermal Performance

Source: The Thermal Performance of Light-Frame Assemblies, Canadian Wood Council

Products Dimension Lumber Studs, Headers, Built-up Columns „ Solid S lid SSawn

Thermal Performance

Source: The Thermal Performance of Light-Frame Assemblies, Canadian Wood Council

Products Engineered Lumber Products „


„ „




2x4 to 2x14 (20ft to 26ft)

Fi Finger-Jointed J i t d Vertical Stud Use Only (12ft) „

2x3 to 2x6

Structural Finger Joint (32ft to 40ft) „ HRA or Non- HRA ((Heat Resistant Adhesive))


„ „

H d Headers and d Columns C l „

2x3 to 2x12

Structural Composite Lumber (SCL) „



Laminated Veneer Lumber (LVL) Laminated Strand Lumber (LSL) Glue Laminated Lumber


LSL LVL LSL, LVL, Glu Glu-Lam, Lam Parallel Strand Lumber (PSL)

Glue Laminated Lumber

Design g Considerations

Products Engineered Lumber Products Code Evaluation Reports

Vertical Load

ƒ Vertical Load

AC202 – Acceptance Criteria for Wood-Based Studs „ 6.0 6 0 Evidence Submitted Ex.: 6.2 Data in accordance with the ICC-ES Acceptance Criteria for Wood-based Studs (AC202), dated June 2009. 2009 „


Roof/Snow and dead

ƒ Lateral L l LLoad d „ „

Unifo orm Wind P Pressure


Combined Loads

Wind load (⊥ to wall plane) Wind and Seismic ((// to wall pplane)) Deflection n


Vertical Load

Uniform Wind Pressure

Top View of Wall Header

Design Considerations Buckling Height Limits ƒ Every column has a height limit to prevent buckling ƒ Max height = 50d (d= depth in inches)

Stud or Column

Design Considerations National Design g Specification p (NDS) ( ) Eqn 15.4-1


3½” (2x4) Max Height: 14’ 1½”:: 8’ 1½ 8 height limit between blocking…

Stud or column in a sheathed wall is braced against buckling in this direction.

5½” (2x6) (2 6) Max M Height: H i ht 22’22’-6” 7¼” (2x8) Max Height: 30’

Stud or column in a sheathed wall is not braced against buckling in this direction.

Eqn 3.7-1 Eqn q 15.3-1 – multiple p Cp p byy Kf for built-upp columns

Design Considerations

Design Considerations

NDS notations t ti „

NDS notations t ti

CP „ c = 0.9 for SCL and GLB „ c = 0.8 for sawn lumber


Emin′ = E[1-1.645COV E[1-1 645COVe](1.03)/1.66 ](1 03)/1 66 „ E = Eapparent „ COVe = 0 0.25 25 to 0.095 0 095 „ Ke = 0.85 to 1.0 to determine le „

Design Considerations

Design Considerations

Allowable Design Stresses

NDS notations „

Design  Stresses

DF‐L #2

SP #2


CP „ FcE = 0.822 Emin′/(le/d)2







2250 to  2950


Fb psi





1700 to  2360

E x 106 psi





1.3 to 1.6


1.5 to 2.0


Fv psi





400 to  410


250 to  290


Fc// psi



1350 to  1700 to  1400 to  1550 2300 2175


2350 to  3200


e = eccentricity „

1/ 6

of the wall thickness 1/





Design Tools

Wind Loads

Exposure ‘B’

Exposure ‘C’

Design Tools

Design Tools

Exposure ‘D’

Framing Details

Framing Details Bracing?

Framing Details

Framing Details

Framing Details

Framing Details

Framing Details


Nailingg Spacing „ Lateral and withdrawal values „

Dependent on specific gravity of product „ Specific gravity varies between face and edge „

Hold-downs Bolt values „ screws „

Multiple Resources for Fire-rated assemblies Solid Sawn IBC „ Gypsum Association GA-600-2009 GA 600 2009 www.gypsum.org „ American Wood Council Design g for Code Acceptance 3 www.awc.org „

Finger-Jointed Stud „

HRA mark required




Check manufacturer’s code evaluation report May be a direct substitute in sawn lumber assemblies „ May be reduction to allowable design stresses „ May M need d additional ddi i l insulation i l i

Fire Retardant Treatments „


LSL, LVL, PSL check with the manufacturer „


Glue-laminated members check with manufacturer „


Most don’t allow – voids warranty Not recommended

Lumber „


Design Value Reductions – 0.80 to 0.98 „ Galvanized or stainless steel fasteners – reductions apply – 0.91 to 0.98 „

Innovative Solutions ƒ Tilt-up LSL wall

Innovative Solutions I-Joists J as wall studs? Advantages Reduced capacity for thermal bridging „ Thicker walls / More insulation „

Disadvantage Not code evaluated „ Non-rectangular Non rectangular shape „ Special detailing required „ No load tables „

Thank Th k You Y