wsf toronto nov 2015 kr shearwalls -...

Canadian Wood Council | cwc.ca Toronto WSF 2015

A. Robertson, P.Eng, K. Rocchi, E.I.T. 1

Adam Robertson, M.A.Sc., P.Eng. & Kevin Rocchi, M.A.Sc., E.I.T.

support@woodworks‐software.com

November 24th 2015

Toronto, ON1

Copyright Materials

This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the

speaker is prohibited.

© Canadian Wood Council 2015



Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available

upon request.

This course is registered with

AIA CES for continuing 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 ofhandling, 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.

Performing a complete lateral load analysis for a building is one of the most complex aspects of

structural design. WoodWorks® Shearwalls software allows engineers to quickly generate wind and seismic

loads according to the NBC 2010 and design wood-frame shearwalls according to CSA O86-09 or -14.

Deflection of shearwalls and force distribution based on flexible and rigid diaphragm distribution methods,

including torsion, are just some of the topics that will be discussed and demonstrated. Along with an overview

and demonstration of the Shearwalls software, an explanation of the updated technical changes in conformance to CSA O86-14 will be presented.

CourseDescription



LearningObjectives

Key learning points:

• How to generate wind and seismic loads for any location in Canada.

• Understand how lateral loads are distributed and resisted using wood-frame shearwalls.

• Overview of technical changes between CSA O86-09 and -14.

• How to layout the lateral-force-resisting-system using WoodWorks® Shearwalls(including import of CAD drawings).

At the end of the this course, participants will be able to:

The Canadian Wood Council represents the Canadian wood products industry through a

national federation of Associations:



CWC produces and communicates technical information to architects, engineers, builders, and other designers on how to use wood in buildings from a structural, fire,

and sustainability design perspective.

www.cwc.ca

7

SHEARWALLS

CONNECTIONS

SIZERGravity Design

Lateral Design (Wind and Seismic)

Fasteners

Concept mode

Column modeBeam mode

DATABASE EDITORAdd proprietary products

CDN Standard

Electronic copy of CSA O86 included with purchase of Design Office suite

($205 value) 8



Toggle Between Design Codes

9

New Feature – Toggle design code between CSA O86-09 and CSA O86-14

SHEARWALLS

CONNECTIONS

SIZERGravity Design

Lateral Design (Wind and Seismic)

Fasteners

Concept mode

Beam modeColumn mode

DATABASE EDITORAdd proprietary products



• PART 1: Sizer, Connections: An Overview and Demonstration with Updates to CSA O86-14

• PART 2: Analysis and Design for Wind and Seismic Loads using Shearwallswith Updates to CSA O86-14

11

Part 4:• Engineered Design• CSA O86

Part 9:• Prescriptive Design• Section 9.23.13 of NBC

WoodWorks Software Follows a Part 4 Design

Required amount of wall bracing, Further Guidance Provided in CWC

“Engineering Guide for Wood Frame Construction” (Available

through CWC Webstore)

NBC Part 4 vs. NBC Part 9

12



CAD Import Drawings as a template makes modeling quicker (.pdf, .bmp, .wmf, .emf)

SHEARWALLS

0,0 20 ft

Wind and seismic load generation at the click of a button. Enter City, or building code climatic info.

SHEARWALLSLateral Design (Wind and Seismic)

Forces are distributed using both rigid (stiffness) and flexible (tributary area) diaphragm assumptions.

Additional loads can be added manually.

Shearwalls designed for worst case distribution and load

14



Wind load design procedure selection (I-15 or I-7/8)


15

Low rise I-7(Lateral - MWFRS)


16



Low rise I-8 components and cladding for…• sheathing • fastener withdrawal


17

All-heights I-15(MWFRS and C&C)


18



Hills and Escarpments input


19

SHEARWALLSRough or Open Terrain option

20



F = m* aV = W* S(Ta) *factors

Newton’s Second Law

S(Ta) = Acceleration as a function of TaTa = Fundamental period of buildingW = Weight of buildingMv = Higher mode effect factorIE = Importance factorRd = Ductility‐related force modification factorRo = Overstrength‐related force modification factor

Seismic

V = W x S(Ta) x Mv x IE / (RdRo)

21

Seismic

Equivalent Static Force Procedure, allowed if:

– Seismic IEFaSa(0.2) < 0.35, any structure

– Any seismic IEFaSa(0.2), Regular shape, H < 60 m, Ta < 2 s

– Any seismic IEFaSa(0.2), Irregular shape*, H < 20 m, Ta < 0.5 s

*except torsional sensitivity where Dynamic analysis required; software automatically detects and notifies

Typical wood structures: T < 0.50 seconds, H < 20 m (65 ft)22



Load Generation and Site Information

23

• Importance category

• q1/50 vel. pressure by location or manually input

• Internal pressure added to C&C for sheathing / nails

• Terrain and Hill shape

24

WindSHEARWALLS



Code Period calculated based on building height 0.05 (hn)3/4

with user override

Ductility Rd & Overstrength Ro

auto determinedDefault: wood sheathed, no GWB

Site class (soil) (geotech report)

Spectral accelerations automatic based on geographic location (climatic data)

25

SHEARWALLS

Seismic

26

SHEARWALLS



Seismic and Wind design data

27

Seismic hazard values

http://earthquakescanada.nrcan.gc.ca/hazard/interpolator/index_e.php

Sa(T): Ottawa

28



SHEARWALLS

Distributes the automatically generated loads to each shear wall

Rigid diaphragm(Stiffness)

Flexible diaphragm(Tributary area)

31

Envelope Design Approach• Program automatically designs shearwalls for the

worst case of wind and seismic for both flexible and rigid diaphragm distribution

• i.e. 4 loading cases for each segment – program designs for worst case scenario

• Light-frame wood structures should behave somewhere between flexible and rigid diaphragm distribution.

• The envelope procedure ensures that all possible loading cases are taken into account for the design.

32



Rigid and Flexible distribution

33

Deflection Based Rigidity (Default Setting):• Program equalizes deflection along a shearline, by equalizing

deflections along each segment within the shearline

Deflection-based rigidity vs. Capacity-based rigidity

Rigidity: 1/ deflection = stiffness34



Flexible distribution to the shearline

Deflection-based distribution within the Shearline

35

36

Force distribution within shearlines

Rigidity: 1/ deflection = stiffness



Capacity Based Rigidity:• The forces are distributed to a shearline based on the relative

capacity of the shearline

Deflection-based rigidity vs. Capacity-based rigidity

Rigid: capacity approximates stiffness37

Flexible distribution to the shearline

Capacity-based distribution within the Shearline

38



39

Force distribution within shearlines

Rigid: capacity approximates stiffness

Hold-downs and Anchorages

40



Typical light-frame Wood Building Designed Following Part 9 of the NBC

(Prescriptive Design)No Hold-downsrequired. Does not follow an Engineered Design

41


(Engineered Design)Hold-downson each Segment(Jhd=1.0)

42



• Overturning tension force is resisted by the sheathing

Sheathing Tension Zone

• Nails resist overturning

Only remaining sheathing and nails can be used for shear resistance, reduced by Jhd

0.1212

S

S

S

S

hd

ijhd L

H

L

H

V

PJ

Studs and hold‐down transfer shear, no impact on sheathing

Shearwall Segments Without Hold‐downs

43


(Engineered Design)Hold-downs where required or replaced by anchorage (Jhd<1.0)

44



45

Design with or without hold downs…

46



Shearwalls Demonstration

• File import

• Add interior shearwalls

• Add openings

• Break shearlines and shift walls

• Lateral wind and seismic, C&C wind load automatic generation

• Basic design output and log files

Understanding the results



Log File

Failing walls are highlighted red in plan view…

And labeled in elevation view



cont…



“S” indicates that seismic design governed the selection of this wall.

Wall Group (W Gp) shown here corresponds to the wall group shown on the sheathing and framing tables.



Design Group 2 Shearwallconstruction

C&C loads used for sheathing design and fastener capacity

Shear wall force

Shear wall force at top per unit length

Drag strut forces due to openings

Shear wall force at base of segments

Hold down forces



Information that can be used to create shearwallschedules:

Results in Word:

Wall Sheathing: Grade/ Fasteners Spacing

Grp Surf Material Ply Thk Or Bv Dia Len Pen

Edg Int Bk Jub #

1 Ext DF Plywood 3 7.5 Horz 4600 2.84 2 43 150 300 Y 1.0

1 Int GWB - 12.5 Horz 7005 - 1-1/2 26 200 300 Y 1.0 10

2 Both GWB - 12.5 Horz 7005 - 1-1/4 19 150 300 Y 1.0 10

3 Both GWB - 15.9 Horz 7005 - 2-1/4 41 150 300 Y 1.0 10

SHEATHING MATERIALS by WALL GROUP [mm]



How to Design a Single Shearwall?

SHEARWALLS - CSA O86-14 Changes

Shear Resistance of Shearwalls

66

► Design Provision in O86-09 (Clause 9.5.1)

CSA O86-09 Shearwall Resistance Design Methodology:• Based on test data of D.Fir-L wall framing assemblies, adjusted for density of framing• Limited to assemblies constructed with dimension lumber, common nails and

sheathing of discrete thickness




67

►Design Provision in O86-14 (Clause 11.5.1)

CSA O86-14 Shearwall Resistance Design Methodology:• Two Design Checks• Mechanics Based Approach• More engineering sense• More Flexibility in terms of assemblies

1. Sheathing-to-framing Connection

2. Sheathing Panel Buckling




68



= 0.8= factor for diaphragm and shearwall construction= 1.3 (Typically)

= number of shear planes in sheathing-to-framing connection= 1 or 2





69



Nu = N, Lateral Strength Resistance (Clause 12.9.4)s = mm, fastener spacing along panel edges

Seismic Design Required to fail as per d), e) or g) to ensure ductility



70



Edge Spacing (mm)

150 125 100 75 50

Js 1.00 0.999 0.990 0.946 0.818




71



Panel Buckling Strength, kN/m




72



When Does Panel Buckling Govern?

From the 2014 Engineering Guide for Wood Frame Construction

Calculation based on maximum size of the panel (ie. 1200 mm x 2400 mm or 4 ft x 8 ft)





73

Fastener Type Changes in Shearwalls 9.3

O86-09 O86-14


Shear Resistance of Shearwalls - Example

74

► O86-09 (Clause 9.5.1)

► O86-14 (Clause 11.5.1)

12.5 mm CSP sheathing; 3.25 mm diameter nails; 150 mm fastener spacing along panel edges;

300 mm fastener spacing along intermediate supports; 400 mm on center stud spacing; S-P-F framing members;

Panel Edges Blocked; Hold-downs on all Segments

Vhd = 0.7 x 7.1 x 1.15 x 0.8 = 4.57 kN/m

Lateral Resistance

BucklingResistance





75

Detailed Shearwalls Design



76

Detailed Shearwalls Design

Vhd = 0.8 x (0.6277 kN / 0.15m) x 1.15 x 1.3 = 5.00 kN/m

Vrs = 0.8 x 25.31 x 1.15 = 23.28 kN/m





77

Detailed Shearwalls Design – Ductility for Seismic9.5 mm CSP sheathing; 2.87 mm diameter nails (2 in long);

150 mm fastener spacing along panel edges; 300 mm fastener spacing along intermediate supports;

400 mm on center stud spacing; S-P-F framing members; Panel Edges Blocked; Hold-downs on all Segments;

15.9 Gypsum underlay



Detailed Shearwalls Design – Ductility for Seismic

How to avoid non-ductile failure?

In this example increase nail length (2” to 2.25”)




Shearwall Deflection – Nail Deformation en

79

as

sns

s

s

ssw d

L

HeH

B

vH

LEA

vH 0025.0

3

2 3



80

► Design Provision in O86-09 (A.9.7)





81

► Design Provision in O86-14 (A.11.7)




∆2vH3EAL

vHB

0.0025H eHLd


Shearwall Deflection – Deflection Output

SHEARWALLS - CSA O86-14 ChangesShearwall Deflection – Deflection Output

► O86-09 (A.9.7)

► O86-14 (A.11.7)

Ex1: 3.25 mm dia. Nails, 2.5 in long, 4 kN, 150 mm edge spacing.



SHEARWALLS - CSA O86-14 ChangesShearwall Deflection – Deflection Output

► O86-09 (A.9.7)

► O86-14 (A.11.7)

Ex2: 3.66 mm dia. Nails, 2.5 in long, 4 kN, 150 mm edge spacing.


86



Mid-rise Structures

Additional training & information:

1. User Guide (pdf) – Updated September 2015 (Go to Website to Download PDF)

2. Video tutorials on website

3. See ‘help’ menu for engineering questions and assumptions



Purchase online:

www.woodworks-software.com

$995

Design Office includes PDF of CSA O86 $205 value

Discounts for multi-seat purchasesDiscounts for upgradesSizer stand-alone available at lower cost

Free for educators and building officials

Questions/ Comments?

Kevin Rocchi, M.A.Sc., E.I.T. & Adam Robertson, M.A.Sc., P.Eng.

woodworks‐software.com

This concludes The American Institute of Architects Continuing Education

Systems Course

Canadian Wood CouncilWood WORKS! Alberta

www.cwc.cawww.wood-works.org

wsf toronto nov 2015 kr shearwalls -...

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