lateral design considerations for mid-rise wood … · lateral design considerations for mid-rise...

Lateral Design Considerations for Mid-Rise Wood Structures

Marselle Condominiums Trochalakis, PLLC Photographer: Matt Todd Photographer

5 stories of wood over 6 stories concrete (podium) 2 above grade

By: R. Terry Malone, PE, SESenior Technical DirectorArchitectural & Engineering Solutionswww.woodworks.org

E-mail: [email protected]

120 Union, San Diego, CATogawa Smith Martin

This presentation is copyrighted by Woodworks

Mid-rise Codes and Standards

CrescentTerminusbuilding- credit:RichardLubrant.

The analysis techniques provided in this presentation are intended to demonstrate one method of analysis, but not the only means of analysis. The techniques and examples shown here are provided as information for designers to consider to refine their own techniques.

Course Description

Research, full-scale testing and code requirements continue to evolve for mid-rise construction. This presentation will focus on important engineering considerations related to the lateral design of mid-rise* wood buildings. Implementation of a well-considered design requires the understanding of diaphragm and shear wall flexibility and their effects on the horizontal distribution of forces through the structure. In mid-rise, multi-family buildings, corridor only shear walls are becoming very popular as a way to eliminate exterior shear walls. The special design issues this situation creates will be addressed.

*Definition:A mid-rise building can be described as something between a high-rise and low-rise structure —that is, between four and ten stories with heights ranging between 35 to 75 feet tall.

Learning Objectives• Design Considerations

Discuss important lateral engineering issues that need to be considered to successfully design a mid-rise structure.

• Diaphragm and Shear Wall FlexibilityUnderstand the relationship between diaphragm and shear Wall stiffness on the horizontal distribution of shears within a mid-rise structure.

• Tall Shear Walls With Multi-story EffectsDiscuss the behavior of shear walls under multi-story effects and the impact on the distribution of shear forces within the structure.

• Overview-Open Front and Non-Open Front StructuresReview key points in the analysis of open front diaphragms and non-open front designs.

Presentation Topics

• Design Considerations

• Complete Load Paths

• Diaphragm Flexibility

• Tall Shear Walls-Flexibility

• Horizontal Distribution of Shears

• Overview-Mid-rise: Exterior shear Walls

• Overview-Mid-rise: Open Front


Design ConsiderationsMethods of analysis for open-front or tall shear wall mid-rise structures are currently evolving as more complex building geometries are becoming more prevalent. Building shapes and footprints are driving the design procedures for all lateral resisting systems and materials.

Design requirements:

• IBC1604.4- Analysis:o Method of analysis shall take into account equilibrium, general stability,

geometric compatibility, and both short-and long term material properties.

o Shall be based on rational analysis in accordance with well established principals of mechanics. Analysis shall provide complete load paths.

Considerations:

• Make sure that you have complete continuous lateral load paths.

• Address vertical / horizontal irregularities.

• Investigate diaphragm and shear wall flexibility/stiffness.

• Consider the multi-story effects on shear wall stiffness.

• Check the effects of offset diaphragms and shear walls.

• Verify the horizontal distribution of forces within the diaphragm and to the shear walls.

76’

35’

6’

35’

Open Front & Non-open Front Floor Plan w/ and w/o offsets

7654321

Typical Unit

F

C

B

A

D

E

Open Front

Non-Open Front

8

SWTypical

SWTypical

Typical Unit

• ASCE 7-10 Section 12.3.1.1- (c), Light framed construction, meeting all conditions:

§ Longitudinal-Typically permitted to be idealized as flexible, provided exterior shear walls of adequate stiffness exist. However, diaphragm can be semi-rigid, rigid or open front, even if exterior walls exist.

§ Transverse-Traditionally assumed to be flexible diaphragm.

§ If token or questionable wall stiffness occurs at the exterior wall line, consider using semi-rigid analysis using the envelope method-(conservative), or semi-rigid, or idealize as rigid.

Non-open front

Open Front Structures:• SDPWS 4.2.5.2 :

§ Loading parallel to open side - Model as semi-rigid, which shall include shear and bending deformation of the diaphragm, or it can be idealized as rigid.

§ Loading perpendicular to open side (Transverse)-traditionally assumed to be flexible.

§ Drift at edges of the structure ≤ the ASCE 7 allowable story drift whensubject to seismic design forces including torsion, and accidental torsion(strength, multiplied by Cd). No set drift requirements required for wind (Drift can be tolerated).

Includes flexible and rigid analysis

Presentation Topics








120Union,SanDiego,CATogawaSmithMartin

Strut/chord

Open

3

4

4

21

FE

D

C

B

5 8 96 7

Strut/chord St

rut (

typ.

)

Strutchord

Strut chord

Strut /chord

Strut/chord

Strut/chord

SW1

SW5

SW2SW3 SW4

Stru

t

MR

F1

Multiple offsets

Offset struts

Support Support

Col

lect

or

Collector

Collector(typ.)

Collector(typ.)

Collector (typ.)

Col

lect

or (t

yp.)

Analysis: ASCE7-10 Sections:• 1.3.1.3.1-Design shall be based on a rational analysis• 12.10.1-At diaphragm discontinuities such as openings and re-entrant

corners, the design shall assure that the dissipation or transfer of edge (chord) forces combined with other forces in the diaphragm is within shear and tension capacity of the diaphragm.

Complete Load PathsDiscontinuousdiaphragm chords

Offset shear wallsand struts

ASCE7-10 Section 1.4-Complete load paths are required including members and their splice connections

Openingin diaph.

Vertical offset indiaphragm

SW8

10

A

Strut/chord

Open

3

4

5

21

FE

D

C

B

6 9 107 8

Strut/chord St

rut (

typ.

)

Strutchord

Strut chord

Strut /chord

Strut/chord

Strut/chord

SW1

SW5

SW2SW3

SW6

SW4

Stru

t

MR

F1

Support Support

Col

lect

or

Collector

Collector(typ.)

Collector(typ.)

Collector (typ.)

Col

lect

or (t

yp.)

A

Complete Load Paths

ASCE7-10 Section 1.4-Complete load paths are required including members and their splice connections

SW7

SW8

Transfer area

Collectors for shear transfer to individual full-height wall segments shall be provided.

SDPWS 4.3.5.1Where offset walls occur in the wall line, the shear walls on each side of the offset should be considered as separate shear walls and should be tied together by force transfer around the offset (in the plane of the diaphragm).

4

Presentation Topics









Average drift of walls

Is maximum diaphragm deflection (MDD) >2x average story drift of vertical elements,using the Equivalent Force Procedure of Section 12.8?

Maximum diaphragm deflection

Envelope MethodAllowed for semi-rigid modelling

Is diaphragm untopped steel decking or Wood Structural Panels

Idealize as

flexible

Is span to depth ratio ≤ 3and having no horizontal irregularities ?

Is diaphragm concrete slab or concrete filled steel deck ?

Structural analysis must explicitly include consideration of the stiffness of the diaphragm (i.e. semi-rigid modeling), or calculated as rigid in accordance with 2015 IBC Section 1604.4 or ASCE 7-10 Section 12.3.1.3.

12.3.1.1- Is any of the following true?

1 & 2 family Vertical elements one Light framed constructionDwelling of the following : where all of the following are

met:1. Steel braced frames 1. Topping of concrete or2. Composite steel and similar material is not

concrete braced frames placed over wood structural3. Concrete, masonry, steel SW panel diaphragms except

or composite concrete and for non-structural topping steel shear walls. not greater than 1 ½” thick.

2. Each line of vertical elements of the seismic force-resisting system complies with the allowablestory drift of Table 12.12-1.

Idealizeas rigid

Idealize asflexible

Yes

YesYes

No

No

No

NoNo

Star

tASCE7-10 Section 12.3 Diaphragm Flexibility Seismic

Yes

Yes

Section 12.3.1- The structural analysis shall consider the relative stiffnesses of diaphragms and the vertical elements of the lateral force resisting system.

(Could apply to CLT or Heavy timber diaphragms)

Is diaphragm untopped steel decking , concrete filled steel decks or concrete slabs, each having a span-to-depth ratio of two or less?

Yes

Yes

No

Diaphragm canbe idealized asflexible

Is diaphragm ofWood Structural Panels ?

Diaphragm canbe idealized asrigid

No

Is diaphragm untopped steel decking , concrete filled steel decks or concrete slabs, each having a span-to-depth ratio greater than two ?

Justify by Calculation as flexible, semi-rigid or rigid per 2015 IBC Section 1604.4 or ASCE 7-10 Section 12.3.1.3.

ASCE7-10, Section 26.2 Diaphragm Flexibility Wind

Start

Yes

ASCE 7-10 Section 27.5.4-Diaphragm flexibilityThe structural analysis shall consider the stiffness of diaphragms and vertical elements of the MWFRS

Wind

Presentation Topics









Current Examples of Mid-rise Analysis-Traditional Method

• APEGBC Technical & Practice Bulletin � Revised April 8, 2015 “5 and 6 Storey Wood Frame Residential Building Projects (Mid-Rise)”-Based on FPInnovations Mechanics Based Approach

• FPInnovations-Website ”Seismic Analysis of Wood-Frame Buildings on Concrete Podium”, Newfield

• Shiotani/Hohbach Method-Woodworks Slide archivehttp://www.woodworks.org/wp-content/uploads/HOHBACH-Mid-Rise-Shear-Wall-and-Diaphragm-Design-WSF-151209.pdf

• Design Example: ”Design of Stacked Multi-Storey Wood-Based Shear Walls Using a Mechanics-Based Approach ”, Canadian Wood Council

Current Examples of Shear Wall Multi-story Effects and Mid-rise Analysis

FPIMBA

Traditional+ moment

Traditional

• 2016 WCTE: A Comparative Analysis of Three Methods Used For Calculating Deflections For Multi-storeyWood Shear Walls: Grant Newfield, Jasmine B. Wang

• FPInnovations-Website ”A Mechanics-Based Approach for Determining Deflections of Stacked Multi-Storey Wood-Based Shear Walls”, Newfield

NEW

http://www.woodworks.org/education/online-seminars/• Thompson Method-Woodworks Website

Webinarhttp://www.woodworks.org/wp-content/uploads/5-over-1-Design-Example.pdf

Paper

Current Examples of Mid-rise Analysis-Mechanics Based Approach

• SEAOC/IBC Structural Design Manual, Volume 2. 2015. Structural Engineers Association of California. Sacramento, CA

Not currently addressed or required by code

StackedShearWallElevationTraditionalMethod-Thompson Example

Source:WoodWorks Five-StoryWood-FrameStructureoverPodiumSlabDesignExample

Traditional Shear Walls: • Max. A/R=3.5:1• Walls assumed to be pinned at

top and fixed at the bottom at eachfloor,

• rigid wall sections and, • out-of-plane diaphragm stiffness-

rigid • Doesn’t account for multi-story

shear wall effects

∆"#=%&'(

)*++ &'

.///01+ '∆1

+

+

+

VR

V3

V2

∆2= ∆34.+∆345 + ∆34(

++

Shiotani / Hohbach Method

Equivalent beam/column

∆34=6 78'8

5 (92 −'8;)<2

VR

V3

V2

• The equation is judged to be adequate as long as the aspect ratios of the walls are reasonable

• Shear wall deflections are approximated based on this equation and extrapolated for multistory behavior.

• Shear walls for this building type have continuous rod tie down systems that are integral to their multistory behavior.

• column elements simplify the model, over shell or plate elements.

• Calculate the deflection of the wall’s story(s) components

• A column section is used, then back calculated for the required moment of inertia to produce the expected deflection at the top of the multi-story shear wall.

• The sum of those deformations are greater than the traditional multi-story shear wall deflections

Procedure• Break the wall up into multi story components

• Provides a reasonable approximation for shear wall deflection (conservative).

Hohbach-Lewin, Inc.-Structural and Civil Engineers

• It also captures the flexural deformation of the full height wall.

∆34=6 78'8

(

()<278

A/R h/d ≤ 2:1

New Research and Analytical methods-Tall Shear WallsCurrently not addressed or required by code:Engineering preference and/or judgement

• Current research suggests that The traditional method of shear wall analysis might be more appropriate for low-rise structures.

Trad

ition

al

Met

hod

Tall

Wal

lM

etho

d

Testing shows that the traditional deflection equation is less accurate for walls with aspect ratios higher than 2:1.(Dolan)

Tall Shear WallMBA

Floor to floor A/R’s and Stiffness of Shear Walls

• Multi-story walls greater than 3 stories should:

§ Consider flexure and wall rotation.

§ Rotation and moment from walls above and wall rotation effects from walls below.

=>

Tall =>

Stiff

ness

bas

ed a

ppro

ach

∆?@@AB CDAEFGEHID

Allowable story drift for traditional and tall shear walls is checked floor to floor.

Total displ. of Tall Wall. More flexible.

A/R=3.5:1flr.-flr.

Total displ. Traditional walls

A/R=2:1flr.-flr.

Act

ing

as a

con

tinuo

us w

all

∑K8L85

5 )< 8+ ∑78 L(

( )< 8

Moment from walls above

Rotation from walls above and below.

Rim joist

Should consider as flexible because it is unknown where rim joist splices will occur

Platform framed

Semi-balloon framed(Very flexible)

Flexibility does not allow dead load to aid in resisting wall rotation

Stiffness might allow dead load to aid in resisting wall rotation, provided joints are strategically placed. (justify by calculation)

If diaphragm out-of-plane stiffness=FlexibleAnalyze entire wall as a tall wall

If diaphragm out-of-plane stiffness=Rigid (steel beam, conc. beam) Analyze entire wall as traditional floor to floor

Compression blocking

V

CT

M

Diaphragm out-of-planeFlexibility

Tall Wall Deflection

α1

θ.

∆1

α2

θ2

∆2

+

θ3

∆3

+α3

θ4

∆4

+α4

∆5

+N. L5 + L(

N. L5

N. L5 + L( + LO

N. L5 + L( +LO + LP

+α.(L. + L5)

98

α1

α.L.98

α.(L. +L5)

98

Deflection-Bending Deflection-Wall rotation)

TUV@WGXG HU∆.

translates to top translates to top

(Wall rotation)

+ +

+Rotation

+α.(L. + L5+L()

98

+α.(L. + L5+L( + LO)

98

+α.(L. + L5+L( +LO + LP)

98

∆8=∑K8L8

5

5 )< 8+ ∑78 L(

( )< 8+ 78L80&,8Z&,8

+ 0.75L8[\,8 +L898]1,8 + L8 ∑

K^L^)< ^

+7^L^

5

5 )< ^+ L8 ∑

]1,^9^

8_.^`. 8_.

^`.

Note:Increased wall flexibility can increase the period of the building, lowering the seismic force demands.

Presentation Topics









Distribution of shear to vertical resisting elements shall be based on:

• Analysis where the diaphragm is modeled as :o Idealized as flexible-based on tributary area.

o Idealized as rigid-Distribution based on relative lateral stiffnesses of vertical-resisting elements of the story below.

o Modelled as semi-rigid. § Not idealized as rigid or flexible§ Distributed to the vertical resisting elements based on the relative stiffnesses of the

diaphragm and the vertical resisting elements accounting for both shear and flexural deformations.

§ In lieu of a semi-rigid diaphragm analysis, it shall be permitted to use an enveloped analysis.

Average drift of walls

Maximum diaphragm deflection (MDD) >2x average story drift of vertical elements, using the ELF Procedure of Section 12.8?

Maximum diaphragm deflection

Calculated as Flexible

• More conservatively distributes lateral forces to corridor, exterior and party walls

• Allows easier determination of building drift• Can over-estimate torsional drift• Can also inaccurately estimate diaphragm

shear forces

• Can under-estimate forces distributed to the corridor walls (long walls) and over-estimate forces distributed to the exterior walls (short walls)

• Can inaccurately estimate diaphragm shear forces

Note:Offsets in diaphragms can also affect the distribution of shear in the diaphragm due to changes in the diaphragm stiffness.

2015 SDPWS 4.2.5 Horizontal Distribution of Shear (Revised)

I1 I2 I3Rigid or spring Support ??

Exte

rior

shea

r w

alls

Rigid support orPartial support

Support Support

TD1

TD2

TD1

TD2

I1I2I3

Wind Loads as applicableSeismic Loads

Support Support

Full support(SW rigid)

Partial support(DecreasingSW stiffness)

No SW support

If flexible diaphragm

Corridor only SWCondition B

Condition A Condition C

• Flexible• Semi-rigid• Rigid

• Semi-rigid• Rigid

Unit with Exterior Wall Unit without Exterior Wall

Varying Degrees of Stiffness Effects of Exterior Walls

Multi-story Effects of Tall Shear Walls

Note that possible changes in diaphragm flexibility can occur from floor to floor: non-open front (flexible) vs. non-open front/open front (rigid or semi-rigid).

open front?

Semi-rigid?

Flexible?

Effects of openings?

Presentation Topics









The following information is from an on-going example calculation and is subject to further revisions and validation. The information provided is project specific, and is for informational purposes only. It is not intended to serve as recommendations or as the only method of analysis available.

76’

156’

35’

6’

35’

Case Study-Non-Open Front Floor Plan With Offsets

26’ typ.

Typical Unit

7654321

F

C

B

A

1.33 1.67

D

E

A.5

E.5

SW5SW4

SW3SW2

SW1

11.5’ 23’

27’ 35’

Varies’

• Flexible analysis• Rigid analysis• Semi-rigid (Envelope)

• ASCE 7-10 Section 12.3.1.1- (c), Light framed construction, meeting all conditions:§ All Light framed construction§ Non-structural concrete topping ≤ 1 ½”§ Each elements of the seismic line of vertical force-resisting system complies with the

allowable story drift of Table 12.12-1§ Longitudinal-Allowed to be idealized as flexible, provided exterior shear walls exist and

is in compliance with ASCE 7-10 Section 12.3.1.1 (c). If calculations show that the story drift at a line of lateral force resistance exceeds the allowable limit, flexible diaphragm behavior cannot be used.

Open Front

Non-Open FrontMax. A/R=4:1

ATS isolator nut take-up deviceand bearing plate

Coupler

Steel rod

Semi-balloon framing

Platform framing

Automatic Tensioning Systems/Devises

• Restraints are required at roof and each floor level to get best results

• Software programs are available for design

• Must be installed per manufacturers recommendations

Number and size of studs as required by design

Anchorage into foundation as required by calculation and per manufacturers recommendations

Ove

rtur

ning

Res

ista

nce

26’ Cor

ridor

∆ 34abcc.

6’

8’

12’

4’

4’

27’

11.5

’3’

11.5

’

Displ.I1I2I3

Computer Model

Tall or narrow SW

Full depth

M

V

35’

156’

Sym.C.L.

3’23

’Seismic

Moderately stiff. support

. Positive moment

∑ Kdiaph.

Shear Deflection per USDA Research Note FPL-0210

∆e81f'

∆"#*&[c.

∆O∆(∆5∆.

∆O∆(∆5∆.

9’ 9’ 9’ 4’ 4’

Cor

ridor Ext.

SW

∆ 34abcc .

∆ 34[gZ

∆34[gZ

Torsion + acc. torsion

Bending

Check Total deflection-Diaphragm flexibility

Check exterior SW stiffness effectsOffs

et

Offs

et

Shear DeflectionNail slip deflection

Determination of Non-Open Front Diaphragm Flexibility

∆ *&[c.34

∆34[gZ

From Tall wall calc.

From Tall wall calc.

Bending Stiffness = *]5

5

Corridor

Sym.C.L.

5g∆ *

&[c.34

Bending increases at start of offset

Roof Plot- Longitudinal Loads- A/R*=1.5:1 (8’ wall)

Base Line=0

Base Line=0

Base Line=0

End

Offs

et

Offs

et

51.13 k46.4 k43.21 k

80.48

414.2’k

526.55’k

692.1’k

Full cantilever

A/R 1.5:1 wallA/R 2:1 wall

A/R 3.5:1 wallNot fullsupport

Full cantilever

Partialsupport

*Aspect ratios Floor to Floor

Determine Diaphragm and TD Nailing, and Chord ForcesSym.C.L.

TD1TD2

TD1TD2I1I2

I3

26’ 6’

8’

12’

4’

4’

27’11

.5’

3’11

.5’

35’

3’

23’

156’

Chord Slip at TD

TD1

TD2

Longitudinal Loading

Collector 2

Collector 1

TD1 Shear

TD2 Shear

Basic Diaphragm Shear

Drift by semi-rigid or rigid analysis only (Open front)

Spring support If Shear walls

+

Same as

=

Check Story Drift-3D model or 2D plane Grid

+Same

as

=

Collectors

C.M.

ASCE 7-10 12.8.6Story drift check(Non-open front)

W1

W2

or

Collectors

Story Drift Check Longitudinal + Torsion (8’ ext. walls)

Significant shear distributed to corridor walls (cantilever action)

Notice curvature (bending) of offset sections

Maximum drift(open front)

C.M.

ASCE 7-10 12.8.6Story drift check(Non-open front)

Presentation Topics






• Mid-rise: Exterior shear Walls



The following information is from an on-going example calculation and is subject to further revisions and validation. The information provided is project specific, and is for informational purposes only. It is not intended to serve as recommendations or as the only method of analysis available.

Relevant 2015 SPDWS Sections

New definitions added:• Open front structures• Notation for L’ and W’ for

cantilever Diaphragms

Relevant Revised sections:• 4.2.5- Horizontal Distribution

of Shears• 4.2.5.1-Torsional Irregularity• 4.2.5.2- Open Front Structures

(a)

L’

W’

Force

Cantilever DiaphragmPlan

Open front

SW

SW

L’Cantilever DiaphragmPlan

W’

Open front

SW

SW

SWForce

L’

W’

Open front

SW

SW Force

Cantilever Diaphragm

Figure 4A Examples of Open Front Structures

(d)

L’

W’Open front

SW

SW

Force


SW

SWL’


(c)(b)

Open front

4.2.5.2 Open Front Structures: (Figure 4A)For resistance to seismic loads, wood-frame diaphragms in open front structures shall comply with allof the following requirements:

1. The diaphragm conforms to:a. WSP-L’/W’ ratio ≤ 1.5:1 4.2.7.1b. Single layer-Diag. sht. Lumber- L’/W’ ratio ≤ 1:1 4.2.7.2c. Double layer-Diag. sht. Lumber- L’/W’ ratio ≤ 1:1 4.2.7.3

2. The drift at edges shall not exceed the ASCE 7 allowable story drift when subject to seismicdesign forces including torsion, and accidental torsion (Deflection-strength level amplified by Cd. ).

3. For open-front-structures that are also torsionally irregular as defined in 4.2.5.1, the L’/W’ ratio shall not exceed 0.67:1 for structures over one story in height, and 1:1 for structures one story in height.

4. For loading parallel to open side:a. Model as semi-rigid (min.), shall include shear and bending deformation of the diaphragm,

or idealized as rigid.

5. The diaphragm length, L’, (normal to the open side) does not exceed 35 feet.

76’

156’

35’

6’

35’

Case Study-Open Front Floor Plan With Offsets

26’ typ.

Typical Unit

7654321

F

C

B

A

1.33 1.67

D

E

A.5

E.5

SW5SW4

SW3SW2

SW1

11.5’ 23’

27’ 35’

• Rigid analysis• Semi-rigid (Envelope)

Open Front

Non-Open Front

Corridor walls typical

Shear panels are required over corridor walls

Transverse shear wallstypical

No exterior shear wallstypical

Determination of Open Front Diaphragm Flexibility

26’

Cor

ridor

Corridor only shear walls

.∆ 3

4

∆e81f'I1I2I3

Computer Model

6’

8’

12’

4’

4’

27’

11.5

’3’

M

V

23’

156’

Sym.C.L.

3’

K1

Full depth

Seismic

Bending ∆

∑ Kdiaph.

Shear Deflection per USDA Research Note FPL-0210

∆(

Shear DeflectionNail slip deflection

L’ Limit= 35’

• Check drift at edges (extreme corners) including torsion plus accidental torsion (Deflection-strength level x Cd. )

• Seismic-meet ASCE7 drift• Wind-deflections can be tolerated.

Torsion + acc. torsion

Corridor

Sym.C.L.

Final Diaphragm (Total) Deflections

∆O∆(∆5∆.

9.5’ 9.5’ 8’ 4’ 4’

Corr

idor

∆ 34abcc .

Roof

5th Floor

4th Floor

Cor

ridor

. ∆e81f'

6’

8’

12’

4’

4’

27’

11.5

’3’

23’

∆ 34abcc . 35’

∆O∆(∆5∆.

9.5’ 9.5’ 8’ 4’ 4’Co

rrid

or

∆ 34abcc .

∆O∆(∆5∆.

9.5’ 9.5’ 8’ 4’ 4’

Corr

idor

∆ 34abcc .I1I2I3

Seismic

Check for diaphragm flexibility

Verify Diaphragm Flexibility:• If flexible, add blocking• If still flexible, decrease nail spacing

to stiffen up

Reference Materials

http://www.woodworks.org/wp-content/uploads/Irregular-Diaphragms_Paper1.pdf

• The Analysis of Irregular Shaped Structures: Diaphragms and Shear Walls-Malone, Rice-Book published by McGraw-Hill, ICC

• Woodworks Presentation Slide Archives-Workshop-Advanced Diaphragm Analysis

• NEHRP (NIST) Seismic Design Technical Brief No. 10-Seismic Design of Wood Light-Frame Structural Diaphragm Systems: A Guide for Practicing Engineers

• SEAOC Seismic Design Manual, Volume 2

• Woodworks-The Analysis of Irregular Shaped Diaphragms (paper). Complete Example with narrative and calculations.

Method of Analysis and Webinar References

DiaphragmsOpeningsOffsetShearWallsOffsetDiaphragms

Mid-riseDesignConsiderations

Presentation Slide Archives, Workshops, White papers, research reportsInformation on Website

Questions?

R. Terry Malone, P.E., S.E.Senior Technical DirectorWoodWorks.org

Contact Information:[email protected]

This concludes Woodworks Webinar on:Lateral Design Considerations for Mid-rise Structures

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