Designing with AWC’s 2012 National Design
Specification® (NDS®) for Wood Construction
John “Buddy” Showalter, PE
Vice President, Technology Transfer
American Wood Council
Michelle Kam-Biron, PE, SE, SECB
Director of Education
American Wood Council
Copyright Material
This presentation is protected by US and
International Copyright laws
laws. Reproduction,
Reproduction
distribution, display and use of the presentation
without written permission is prohibited.
© American Wood Council 2014
Copyright © American Wood Council
1
Description
AWC's National Design Specification (NDS) for Wood
Construction 2012 is the dual format Allowable Stress
Design (ASD) and Load and Resistance Factor Design
(LRFD) document referenced in US building codes and
used to design wood structures worldwide. Participants will
learn about changes in the 2012 NDS and Supplement
relative to previous editions and gain an overview of the
standard.
standard
Learning Objectives
On completion of this course, participants will:
•
•
•
•
Be able to understand Load and Resistance Factor Design
(LRFD) and how it applies to wood structural design.
Be familiar with the significant changes between the 2005
and 2012 NDS and supplement.
Be able to identify the similarities and differences with
respect to ASD, design values, and behavioral equations
Be
e able
ab e to analyze
a a y e format
o at a
and
d co
content
te t within
t
tthe
e 2012
0
NDS.
Copyright © American Wood Council
2
Polling Question
1. What is your profession?
a) Architect
b) Engineer
c) Code Official
d) Building Designer
e) Other
Outline
• Overview
• LRFD Primer
• NDS
•
•
Chapter-by-chapter discussion
•
Changes from previous editions
•
Summary
M
More
I f
Info.
Copyright © American Wood Council
3
Outline
• Overview
• LRFD Primer
• NDS
•
•
Chapter-by-chapter discussion
•
Changes from previous editions
•
Summary
M
More
IInfo.
f
NDS History
1944
1973
1991
1962
1977
1997
1968
1982
2001
1971
1986
2005
Copyright © American Wood Council
4
NDS History
International Building Code
• SECTION 2306 ALLOWABLE STRESS
DESIGN
•
2306 1 Allowable stress design.
2306.1
design The structural
analysis and construction of wood elements in
structures using allowable stress design shall be
in accordance with the following applicable
standards:
•
American Forest & Paper Association.
•
NDS
National Design Specification
for Wood Construction
• 2307.1 Load and resistance factor design.
• The structural analysis and construction of wood
elements and structures using load and
resistance factor design shall be in accordance
with AF&PA NDS.
Copyright © American Wood Council
5
NDS and Supplement
• 2005
• 16 Chapters
• 14 Appendices
NDS 2012 Approval
• ANSI approval
• August 15, 2011
• 2012 IBC Reference
Copyright © American Wood Council
6
NDS and Supplement
2005
• 16 Chapters
• 14 Appendices
2012
• 16 Chapters
• 14 Appendices
Wood Design Package
2005 Wood Design
Package
Copyright © American Wood Council
2012 Wood Design Package
7
Addenda/Errata
• Publications Addenda/Errata
• Comprehensive List
•
http://awc org/publications/update/index html
http://awc.org/publications/update/index.html
•
Free download
Outline
• Overview
• LRFD Primer
• NDS
•
•
Chapter-by-chapter discussion
•
Changes from previous editions
•
Summary
M
More
IInfo.
f
Copyright © American Wood Council
8
Design Process
Demand  Capacity
Design Process
Load
Support Conditions
Geometry
Materials
Performance
Fire
Economics
Aesthetics
….
Copyright © American Wood Council
Demand
Capacity
9
Design Concepts
Two Limit State concerns:
• Serviceability (performance
in-service)
• Safety against failure or
collapse
Serviceability
• Unfactored loads
• Mean (avg) material
strength values
Copyright © American Wood Council
10
LRFD - Safety
• Factored loads
• Material strength
values - modified
Structural Property Variability
Normal Distribution Curves
x = mean
x = standard deviation
x
x
x
Relative Frequency
R
SCL
x
COVx =
I-Joist
x
Coefficient of variation
Load
Glulam
MSR Lumber
Vi
Visually
ll G
Graded
d d
Lumber
Material Property Values
Copyright © American Wood Council
11
Engineered Wood Design
S>R
Failure
Statistical Model
•
Normal Distribution Curves for Safety Function, Z
fZ = fR - fS
mZ = mR - mS
 z   R2   S2
Safety (or reliability )
Index
m
 z
z
Probability of
failure of
structure
Copyright © American Wood Council
Performance Distribution (Z)
12
Probability of Failure
Pf = one failure
expected for x number
of structures designed
and built with a given 
•
Safety (or reliability
index) Ex.  = 3.2
represents 1 failure for
every 1
1,000
000 structures
or members designed.
•

5.2
4.7
4.2
3.7
3.2
2.7
2.2
Pf
1 : 10,000,000
1 : 1,000,000
1 : 100,000
1 : 10,000
1 : 1,000
1 : 100
1 : 10
LRFD - Range on 
•
•
Structural Design
 Range for Strength Various Materials

Pf
Copyright © American Wood Council
Low
2.4
1 : 25
Typical
2.6
1 : 63
High
2.9
1 : 251
13
LRFD Design Equation
Demand  Capacity
p
y
n

 Q    Rn
i=1

b



= Safety or Reliability Index
= Load Factor
= Reliability Index
= Time effect factor (replaces LDF)
Allowable Stress Design
• What stays the same?
• Same basic equation format
• Same adjustment factors
• Same behavioral equations
Copyright © American Wood Council
14
LRFD vs. ASD
• Three new notations - , , and KF
• Design
g loads (factored)
(
) for safetyy are
bigger
• Design loads (unfactored) for
serviceability are the same
• Material resistance values
are bigger
• Load
d Duration Factor changes
h
to Time Effect Factor
LRFD vs. ASD
•ASD
•applied stress  allowable stress
Theoretical safety
margin applied to
material stresses
Estimated
Loads
Design
Load

Adjusted
Resistance
Tested
material
strength
Design values
Copyright © American Wood Council
15
LRFD vs. ASD
•LRFD
•factored load  factored resistance
Member performance
factor
Load factors to
account for
variations in loads

Estimated
loads
Factored
Design
Load
Factored
Design
Resistanc
e
Tested
member
resistance
Design values
2012 NDS
•
Factored Load Combinations ASCE 7-10
Copyright © American Wood Council
16
NDS 2012 LRFD Specification
•Format Conversion Factor KF:
ASD
RN = CDRASD
LRFD
RN = KF RASD
RASD reference
strengths
2012 NDS
Reliability indices or data confidence factors
Copyright © American Wood Council
17
2012 NDS
Baseline 10 minutes
(ASD uses 10 years)
• tied to ASCE 7 Factored Loads:
Permanent
Long term
Short term
2012 NDS
RN = KF RASD
KF converts reference design values (ASD normal
load duration) to LRFD reference resistance
Copyright © American Wood Council
18
Why use LRFD?
• Ease of designing with multiple
materials
• Does not penalize material strength
for unknowns on loads
• Realize efficiencies with
•
Multiple transient live loads
•
Extreme event loads
• ASD load combinations have not
been maintained in deference to
LRFD load combinations
Polling Question
2. Format Conversion Factor, KF
a) is only used with ASD
b) is not necessary when calculating shear strength
using LRFD
c) converts ASD material reference design values from
the 2012 NDS Supplement for use with LRFD
d) converts LRFD material reference design values
from the 2012 NDS Supplement for use with ASD
Copyright © American Wood Council
19
Outline
• Overview
• LRFD Primer
• NDS
•
•
Chapter-by-chapter discussion
•
Changes from previous editions
•
Summary
M
More
IInfo.
f
NDS 2012 Chapters
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Copyright © American Wood Council
General Requirements for Building Design
Design Values for Structural Members
Design Provisions and Equations
Sawn Lumber
Sa
u be
Structural Glued Laminated Timber
Round Timber Poles and Piles
Prefabricated Wood I-Joists
Structural Composite Lumber
Wood Structural Panels
Mechanical Connections
Dowel-Type Fasteners
Split Ring and Shear Plate Connectors
Timber Rivets
Shear Walls and Diaphragms
Special Loading Conditions
Fire Design of Wood Members
Commentary!!!
20
NDS 2012 Supplement
1.
2.
3.
4.
Sawn Lumber Grading Agencies
Species Combinations
Section Properties
Reference Design Values
•
Lumber and Timber
•
Non-North American Sawn
Lumber
•
Structural Glued Laminated
Timber
•
MSR and MEL
•
Timber Poles and Piles
NDS 2012 Appendices
A.
B.
C.
D.
E
E.
F.
G.
H.
I.
J.
K.
L
L.
M.
N.
Copyright © American Wood Council
Construction and Design Practices
Load Duration (ASD Only)
Temperature Effects
Lateral Stability of Beams
L
Local
l Stresses
St
iin F
Fastener
t
G
Groups
Design for Creep and Critical Deflection
Applications
Effective Column Length
Lateral Stability of Columns
Yield Limit Equations for Connections
Solution of Hankinson Equation
Typical Dimensions for Split Ring and Shear
Plate Connectors
Typical Dimensions for Standard Hex Bolts
Bolts,
Hex Lag Screws, Wood Screws, Common,
Box, and Sinker Nails
Manufacturing Tolerances for Rivets and Steel
Side Plates for Timber Rivet Connections
Appendix for Load and Resistance Factor
Design (LRFD) – Mandatory
21
NDS – Chapter 1
Chapter 1 - Terminology
fb ≤ Fb'
Reference design values (Fb, Ft, Fv, Fc, Fc, E, Emin)
Adjusted design values (Fb', Ft', Fv', Fc', Fc', E', Emin')
Allowable (changed in the 2005)
Copyright © American Wood Council
22
Chapter 1 – Design Loads
• Reference loads
• Minimum load standards
• ASCE 7 – 10
NDS – Chapter 2
Copyright © American Wood Council
23
Chapter 2 – Adjustment Factors
Reliability indices or data confidence factors
Appendix N – Adjustment Factors
 tied to ASCE 7 Factored Loads: Baseline 10 minutes (ASD uses 10 years)
Permanent
Long term
Sh t term
Short
t
Copyright © American Wood Council
24
Chapter 2 – Adjustment Factors
Revised ASTM D5457-10
RN = KF RASD
KF converts reference design values (ASD
normal load duration) to LRFD reference
resistance
Chapter 2 – Adjustment Factors
• Adjusts from reference to site conditions
•
CD ttime-dependent
e depe de t
Copyright © American Wood Council
Baseline 10 years
25
Chapter 2 – Adjustment Factors
• Adjusts from reference to site conditions
•
Ct te
temperature
pe atu e factor
acto
Exposed for “sustained” period
Chapter 2 – Adjustment Factors
• Wet Service
Factor, CM
Copyright © American Wood Council
26
Wet Service Conditions
30
Wood EMC %
25
20
Temp 30 deg F
15
Temp 70 deg F
Temp 130 deg F
10
5
0
0
20
40
60
80
100
Relative Humidity %
%Strength at 12% Moisture
%
e Content
Wet Service Conditions
110
100
90
Impact Strength
80
Modulus of Elasticity
70
Modulus of Rupture
Crushing Strength
60
50
40
12
14
16
18
20
22
24
26
28
30
Moisture Content of Wood (%)
Copyright © American Wood Council
27
Wet Service Factor, CM
• Sawn lumber MC < 19% considered dry
• Otherwise, NDS Supplement for lumber
Polling Question
3. Temperature Factor Ct applies to conditions
where the wood temperatures exceed:
a)
b)
c)
d)
100 degrees F for sustained periods of time
100 degrees F for short period of time
100 degrees F at any time
100 degrees C at any time
Copyright © American Wood Council
28
NDS – Chapter 3
Chapter 3 – Behavioral Equations
ASD vs LRFD – adjusted stresses from
reference
• ASD F′n = Fn CD x adjustment factors
• LRFD F′n = Fn KF n  x adjustment factors
Copyright © American Wood Council
29
Chapter 3 – Behavioral Equations
• Beams
•
CL beam stabilityy
•
Critical Buckling Design Value
for bending members
Chapter 3 – Behavioral Equations
• Beams
FbE Equivalence
1.20E'min K bEE'
FbE 

R b2
R b2
2012/2005
NDS
2001
NDS
•
Emin adjusted for safety for both ASD and LRFD processes
•
RB = Slenderness
Slende ness Ratio
Copyright © American Wood Council
30
Chapter 3 – Behavioral Equations
• Columns
•
CP column stability
Critical Buckling Design Value
for compression members
Chapter 3 – Behavioral Equations
• Columns
•
FcE equivalence
FcE 
0.822E'min
 le 
 
d
2
2012/2005
NDS
Copyright © American Wood Council

K cEE'
 le 
 
d
2
2001
NDS
31
Chapter 3 – Behavioral Equations
E min  1.03 E (1  1.645 (COV E )) / 1.66
E
1.03
1.66
COVE
= reference MOE
= adjustment factor to convert E to a pure bending
basis (shear-free) (use 1.05 for glulam)
= factor of safety
= coefficient of variation in MOE (NDS Appendix F)
OR
Emin values published in NDS Supplement
Chapter 3 – Behavioral Equations
Tension members (tension parallel to grain)
• ASD
F′t = Ft CD
• LRFD F′t = Ft KF t 
Copyright © American Wood Council
x adjustment factors
x adjustment factors
32
Chapter 3 – Behavioral Equations
• Wood and tension perpendicular to grain
•
Not recommended per NDS 3.8.2
initiators:
• notches
• moment connections
• hanging loads
Chapter 3 – Behavioral Equations
• Combined bi-axial bending and axial
compression
Copyright © American Wood Council
33
Chapter 3 – Behavioral Equations
• Combined bi-axial bending and axial
compression
New
Added to account for possible negative value in
denonimator of third term of equation 3.9-3
Chapter 3 – Behavioral Equations
• Bearing perpendicular to grain
•
F′c = Fc CM Ct Ci Cb (ASD)
•
F′c = Fc CM Ct Ci Cb Kf c  (LRFD)
Copyright © American Wood Council
34
NDS – Chapter 4
Chapter 4 – Lumber
•Design values
• Visually graded lumber
• MSR / MEL
• Timber
• Decking
Copyright © American Wood Council
35
Chapter 4 – Lumber
•Lumber
adjustment
factors
• KF and 
Chapter 4 – Lumber
•Lumber
adjustment
factors
• KF and 
Copyright © American Wood Council
36
Chapter 4 – Lumber
• Lumber adjustment factors
• CF - size factor
Chapter 4 – Lumber
• Lumber adjustment factors
Copyright © American Wood Council
37
Chapter 4 – Lumber
• Lumber adjustment factors
• repetitive member
• Cr = 1.15
• 2” – 4” lumber
• < 24” o.c.
• 3 or more
• Load distributing
element
NDS – Chapter 5
Copyright © American Wood Council
38
Chapter 5 – Glulam
• Significant changes
• New adjustment factors
t
ti
• St
Stress iinteraction
• Shear reduction
• Clarified or added
• Curved members
p
• Double-tapered
•
Tapered straight
Chapter 5 – Glulam
• New adjustment factors
Stress interaction
•
•
Tapered
d
•
Timber Construction
manual
Shear reduction
•
•
•
NDS footnote
Non-prismatic
Copyright © American Wood Council
39
Chapter 5 – Glulam
• Clarified or added
• Curved members
• Double-tapered
• Tapered straight
Chapter 5 – Glulam
• Adjustment factors
•
CV Volume Factor
•
CL Beam
B
St
Stability
bilit Factor
F t
•
Not cumulative with CL
•
Min (Cv, CL)
Copyright © American Wood Council
40
Polling Question
4. The two new adjustment factors were added
to glued laminated timber design are stress
interaction and shear reduction factors. T/F
True
NDS – Chapter 6
Copyright © American Wood Council
41
Chapter 6 – Poles & Piles
• Poles - post-frame
• Piles
Pil - foundations
f
d ti
Chapter 6 – Timber Piles
• Design values
•
Significant changes from 2005 NDS
•
Design values moved to NDS Supplement
2005 NDS
2012 NDS
Copyright © American Wood Council
42
Chapter 6 – Timber Poles
2005 NDS
2012 NDS
Chapter 6 – Poles & Piles
• Adjustment factors
•
Cct – condition treatment
•
Cls – load sharing
•
Ccs – critical section
Copyright © American Wood Council
43
NDS – Chapter 7
Chapter 7 – I-joists
• Design values
•
M, V, EI, K – no changes
• Evaluation Reports
•
Contain proprietary design
Copyright © American Wood Council
44
Chapter 7 – I-Joists
• Beam stability factor
• Braced compression flange
• CL = 1.0
• Unbraced compression flange
• Design as unbraced column
NDS – Chapter 8
Copyright © American Wood Council
45
Chapter 8 – Structural Composite Lumber
• No changes from
2005 NDS
• Evaluation Reports
•
Contain proprietary design

Rela
ative Frequency
x = mean
x

SCL
I-Joist
Glulam
COVxx=
x
MSR Lumber
Load
Visually Graded
Lumber
Material Property Values
Chapter 8 – Structural Composite Lumber
• Adjustment factors
• CV – volume
Cv < 1.0
1 0 Not
N cumulative
l i with
i h beam
b
stability
bili factor,
f
CL - then
h min.
i (Cv, CL)
Cv > 1.0 Cumulative with beam stability factor, CL
Copyright © American Wood Council
46
Chapter 8 – Structural Composite Lumber
• Adjustment factors
•
1 04
Cr Repetitive Member Factor=
Factor 1.04
•
Cr is different than lumber (Cr lumber = 1.15)
•
Applies to Fb only
NDS – Chapter 9
Copyright © American Wood Council
47
Chapter 9 – Wood Structural Panels
• Design values – obtain from an approved source
•
FbS
•
FtA
•
Fvtv
•
Fs
•
FcA
•
EI
•
EA
•
Gvtv
•
Fc
Chapter 9 – Wood Structural Panels
• Adjustment factors apply Fb & Ft
CG - grade & construction
•
•
Removed (no longer used by wsp industry)
Cs - panel size
•
•
Clarified
•
Moved from commentary
Copyright © American Wood Council
48
Chapter 9 – Wood Structural Panels
• Adjustment factors
• CM - wet service
• Ct - temperature
NDS – Chapter 10
Copyright © American Wood Council
49
Chapter 10 – Mechanical Connections
• Design issues
• Reference design values
•
Ch t 11 – dowel-type
Chapter
d
lt
connectors
t
((nails,
il bolts,
b lt lag/wood
l /
d screws))
•
Chapter 12 – split rings and shear plates
•
Chapter 13 – timber rivets
• Adjustment factors
• No significant changes
• Connections session
NDS – Chapter 11
Copyright © American Wood Council
50
Chapter 11 - Tabulated Values
• Consistent titles and footnotes
• Penetration assumptions in titles
Chapter 11-Dowels
Copyright © American Wood Council
51
Chapter 11-Dowels
Chapter 11-Dowels
Copyright © American Wood Council
52
Chapter 11-Dowels
Threaded
length < lm/4
lm
Dia. Fastener = D
lm
Threaded
length < lm/4
Dia. Fastener = D
Chapter 11-Dowels
lm
Dia. Fastener = Dr
Copyright © American Wood Council
53
Chapter 11 - Dowels
Provide tools for the analysis
• gaps between members
• various fastener moment resistance
configurations
• fasteners through hollow members
• fasteners with tapered tips
http://www.awc.org/publications/TR/index.php
Chapter 11 - Tabulated Values
•
New post frame ring shank tables
• Based on ASTM F1667
Copyright © American Wood Council
54
Chapter 11 - Dowel Bearing Length
Fastener Type
Tip Length, E
Lag Screws
Appendix L
Wood Screws
2D
Nails & Spikes
2D
E,, ℓs, ℓm < p – E / 2
Chapter 11 - Dowel Bearing Strength
• Wood Structural Panels
•
D < ¼
Copyright © American Wood Council
55
Chapter 11 - Perp to Grain Distance
• Glulam only
Moisture content
•
• Glulam only
•
Moisture content
Polling Question
5. TR 12 includes general dowel equations and
provides tools for the analysis of:
a)
b)
c)
d)
e)
gaps between members
fasteners through hollow members
fasteners with tapered tips
All of the above
None of the above
Copyright © American Wood Council
56
NDS – Chapter 12
Chapter 12 – Split Rings and Shear Plates
• Geometry factor, CD
•
Side Grain
Copyright © American Wood Council
57
Chapter 12 – Split Rings and Shear Plates
• Geometry factor, CD
•
End Grain
NDS – Chapter 13
Copyright © American Wood Council
58
Chapter 13 – Timber Rivets
• Many applications
Chapter 13 – Timber Rivets
Copyright © American Wood Council
59
Chapter 13 – Timber Rivets
• Parallel to grain
• Timber rivet capacity
• Proper application of CD
Timber Rivets – Design 2005 NDS
Copyright © American Wood Council
60
Timber Rivets – Design 2012 NDS
Chapter 13 – Timber Rivets
• Timber rivet capacity
•
Proper application of CD
•
Parallel to grain timber rivet capacity
•
Pr = 280 p0.32 nR nC (13.2-1)
188 2012 NDS
Perpendicular to grain timber rivet capacity
•
•
Qr = 160 p0.32 nR nC
108 2012 NDS
Copyright © American Wood Council
61
Chapter 13 – Timber Rivets
• Maximum distance perpendicular to grain between
outermost rows of rivets shall be 12
• Consistent with glulam
NDS – Chapter 14
Copyright © American Wood Council
62
NDS – Chapter 14
Chapter 14 – Shear Walls and Diaphragms
• ANSI / AWC SDPWS
2008 standard
• Recorded Webinar
•Online course 2005/2008
SDPWS
•Diaphragm Deflection
•www.awc.org
Copyright © American Wood Council
63
NDS – Chapter 15
Chapter 15 – Special Loading
• Built-up columns
•
Flatwise bending check
•
Consistent with Chapter 3
New
Copyright © American Wood Council
64
NDS – Chapter 16
Chapter 16 – Fire (ASD)
• Fire resistance up to
• Columns
• Beams
• Tension
T
i
M
Members
b
• ASD only
• Products
• Lumber
• Glulam
• SCL
• Decking
D ki
Copyright © American Wood Council
two hours
…
65
Chapter 16 – Calculated Resistance
• Fire resistance of
exposed wood members
may be calculated using
the provisions of NDS
Chapter 16
Fire Resistance
Glulam
Copyright © American Wood Council
Steel
66
Performance of Wood vs. Steel
Chapter 16 – Fire (ASD)
T h i l Report
Technical
R
t No.
N 10
Copyright © American Wood Council
67
Chapter 16 – Fire (ASD)
Code Updates Design of Fire
FireResistive Exposed
Wood Members
http://www.awc.org/pu
blications/download php
blications/download.php
Polling Question
6. The IBC includes provisions for calculating
fire resistance of exposed wood members
and wood decking for up to two hours.
hours
True/False
True
Copyright © American Wood Council
68
NDS – Appendices
NDS 2012 Appendices
2012
A Construction and Design Practices
B Load Duration
C Temperature Effects
D Lateral
ate a Stability
Stab ty of
o Beams
ea s
E Local Stresses in Fastener Groups
F Design for Creep and Critical Deflection
Applications
G Effective Column Length
H Lateral Stability of Columns
I Yield Limit Equations for Connections
J Solution of Hankinson Equation
K Typical Dimensions for Split Ring and
Shear Plate Connectors
L Typical
i l Dimensions
i
i
for
f Standard
d d Hex
Bolts, Hex Lag Screws, Wood Screws,
Common, Box, and Sinker Nails
M Manufacturing Tolerances for Rivets and
Steel Side Plates for Timber Rivet
Connections
N Appendix for Load and Resistance Factor
Design (LRFD)
Copyright © American Wood Council
69
Appendix E
• Example E.8
• Acritical check
Appendix L
Copyright © American Wood Council
70
Appendix N
NDS – Commentary
Copyright © American Wood Council
71
Outline
• Overview
• LRFD Primer
• NDS
•
Chapter-by-chapter
discussion
•
Changes from previous
editions
•
Summary
• More Info.
2012 NDS – Notable Changes
• Chapter 5 – Glulam
• Chapter 6 – Poles and Piles
• Chapter 12 – Split Rings &
Shear Plates
Copyright © American Wood Council
72
NDS 2012 Supplement
• New nominal and minimum Timber sizes per PS 20-10
• Section properties distinguish lumber, P&T, B&S
• New Coast Sitka Spruce & Yellow Cedar values
• Revised Northern Species bending and tension values
• Clarify Timber size factor adjustments
• New and revised values for several foreign species
• Revised glulam values - primary changes to shear
• New Tables 6A & 6B for Timber Poles and Piles
Southern Pine Design Values
• ALSC approves design values
• June 1, 2013
• AWC compiles them
• NDS Supplement
• More information
• www.spib.org
• www.southernpine.com
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73
Wood Design Package
• Wood Design Package
• NDS + Commentary
• NDS Supplement
• ASD/LRFD Manual
• Example Problems
• Almost complete
Supplement:
Design Values for
Wood Construction
MANUAL
Future
2015
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74
Coming in 2015 NDS/SDPWS
NDS
•
•
CLT Provisions
Franklin Elementary School
Franklin, West Virginia
Architect: MSES Architects, Fairmont, WV
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Source: LignaTerra
75
Franklin Elementary School
Source: LignaTerra
Franklin, West Virginia
46,200 sq. ft.
8 week assembly
Franklin Elementary School
Source: LignaTerra
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76
Franklin Elementary School
Scheduled completion date: Winter 2015
Coming in 2015 NDS/SDPWS
NDS
•
•
CLT Provisions
SDPWS
•
•
Design Flexible and Open
Front/Cantilever Diaphragms
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77
2015 Special Design Provisions for Wind and Seismic
2015 SDPWS
Overview
• Ch. 2
•
Removes definition of flexible and rigid diaphragms
•
Defines “Open-Front Structure” & “Subdiaphragm”
• Ch. 4
•
Clarification of concrete and masonry wall anchorage
•
Revised Horizontal Distribution of Shear
•
Clarification of shear wall Aspect ratio adjustments
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78
2015 SDPWS
2015 SDPWS
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79
More Details
• White paper - www.awc.org
• Comprehensive table
• Section-by-section changes
• Structure Magazine
• January 2012
Resources
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80
Resources
Questions?
www.awc.org
info@awc.org
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81