Connection Design with the NDS and Technical Report 12 ...
Transcript of Connection Design with the NDS and Technical Report 12 ...
Copyright © 2015 American Wood Council. All rights reserved. 1
Connection Design with the NDS and Technical Report 12 (DES330)
Lori Koch, PEProject EngineerAmerican Wood Council
Michelle Kam-Biron, PE, SE, SECBDirector, EducationAmerican Wood Council 1
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.
© American Wood Council 2015
Copyright Materials
2
1
2
Copyright © 2015 American Wood Council. All rights reserved. 2
3
• The American Wood Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES), Provider # 50111237.
• 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.
Course Description
This course will feature techniques for designing connections for wood members utilizing AWC's 2015 National Design Specification® (NDS®) for Wood Construction and Technical Report 12 - General Dowel Equations for Calculating Lateral Connection Values (TR12). Topics will include connection design philosophy and behavior, an overview of common fastener types, changes in the 2015 NDS related to cross-laminated timber, and design examples per TR12.
4
3
4
Copyright © 2015 American Wood Council. All rights reserved. 3
Learning Objectives
• On completion of this course, participants will:
1. Be familiar with current wood member connection solutions and applicable design requirements.
2. Be familiar with Technical Report 12 and provisions for connection design beyond NDS requirements.
3. Be able to recommend fastening guidelines for wood to steel, wood to concrete, and wood to wood connections.
4. Be able to describe effects of moisture on wood member connections and implement proper detailing to mitigate issues that may occur.
5
Polling Question1. What is your profession?
a) Architect
b) Engineer
c) Code Official
d) Building Designer
e) Other
6
5
6
Copyright © 2015 American Wood Council. All rights reserved. 4
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
7
• Model wood cells as a bundle of straws• Bundle is very strong parallel to axis of the straws
Basic Concepts
Stronger Less strong
Parallel Perpendicular
8
7
8
Copyright © 2015 American Wood Council. All rights reserved. 5
Connecting Wood - Philosophy
• Wood likes compression parallel to grain• makes connecting wood very easy
9
• Wood likes compression parallel to grain• makes connecting wood very easy
Connecting Wood - Philosophy
10
9
10
Copyright © 2015 American Wood Council. All rights reserved. 6
Connecting Wood - Philosophy• Wood likes to take on load spread over its surface
11
Connecting Wood - Philosophy• Wood and tension perpendicular to grain
• Not recommended
Initiators:• notches• large diameter fasteners• hanging loads
12
11
12
Copyright © 2015 American Wood Council. All rights reserved. 7
Notching
Problem Solution
13
Split
Beam to Concrete
• Notched Beam Bearing• may cause splitting• not recommended
14
13
14
Copyright © 2015 American Wood Council. All rights reserved. 8
Beam to Concrete
• Notched Bearing Wall• alternate to beam notch
15
Hanger to Beam
• Load suspended from lower half of beam
• Tension perpendicular to grain
• May cause splits
SplitSplit
C
T
NA
NA
16
15
16
Copyright © 2015 American Wood Council. All rights reserved. 9
Hanger to Beam
Lower half of beam• may cause splits• not recommended
Exception: light load• <100 lbs• >24” o.c.Split
17
Hanger to Beam
• Load supported in upper half of beam
• Extended plates puts wood in compression when loaded
compression
Full wrap sling option
C
T
NA
NA
18
17
18
Copyright © 2015 American Wood Council. All rights reserved. 10
Connecting Wood- Philosophy
• Splitting happens because wood is relatively weak perpendicular to grain
• Nails too close (act like a wedge)
19
Nailing not staggered Nailing staggered
Framing
Wood Structural
Panel
Nail
1/8" GapBetween Panels
Nailing not staggered Nailing staggered
Staggered Nailing
Connecting Wood - Philosophy
20
19
20
Copyright © 2015 American Wood Council. All rights reserved. 11
Splitting will not occur perpendicular to grain,
no matter how close nails are
Splitting occurs parallel to grain
Staggering
Staggering a line of nails parallel to wood
grain minimizes splitting
Connecting Wood- Philosophy
21
Connecting Wood - Philosophy• Wood, like other hygroscopic materials, moves in varying
environments
22
21
22
Copyright © 2015 American Wood Council. All rights reserved. 12
Connecting Wood - Philosophy• Fastener selection is key to connection ductility, strength,
performance
23
Polling Question
24
�� ������������ ���������������������� ���
a) Notches in the beam
b) Hanging loads
c) Large diameter fasteners
d) All of the above
23
24
Copyright © 2015 American Wood Council. All rights reserved. 13
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
25
Connection Behavior
• Balance• Strength –• Ductility-
Load
Displacement
high strength, poor ductility
good strength, good ductility
low strength, good ductility
26
25
26
Copyright © 2015 American Wood Council. All rights reserved. 14
Connection Behavior
27
Connection Behavior
28
27
28
Copyright © 2015 American Wood Council. All rights reserved. 15
Connection Behavior
30
Connection Behavior
Load
Displacement
high strength, poor ductility
good strength, good ductility
low strength, good ductility
• Balance• Strength –
• Size and number of fasteners
• Ductility-• Fastener slenderness• Spacing• End distance
31
30
31
Copyright © 2015 American Wood Council. All rights reserved. 16
Wood Frame Shear Walls• Elements of a wood shear wall
������������������ ��������������� ����
��������������������������� ��� �����������������
��� �������
���������������
�� !�������
"
� #
$
32
Shear Wall Test
• 8 ft x 8 ft wood structural panel shear wall cyclic test
33
32
33
Copyright © 2015 American Wood Council. All rights reserved. 17
Shear Wall Test• Typical failure of sheathing nailing
a) Nail yielding at adjoining b) Nail yielding and head pull through at panel panel edge to bottom plate location
34
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
35
34
35
Copyright © 2015 American Wood Council. All rights reserved. 18
Connection Serviceability
• Issue: direct water ingress• Water is absorbed most quickly through wood end grain
No end caps or flashing
36
Connection Serviceability
• Issue: direct water ingress• Re-direct the water flow
around the connection
end caps and flashing
37
36
37
Copyright © 2015 American Wood Council. All rights reserved. 19
Connection Serviceability• Issue: direct water ingress• Or, let water out if it gets in...
Moisture trap -No weep holes
38
Moisture Changes In Wood
Causes dimensional changes perpendicular to grain
Growing tree is filled with water
As wood dries, it shrinksperp. to grain
Tang
entia
lly
Radially
39
38
39
Copyright © 2015 American Wood Council. All rights reserved. 20
Wood Shrinks
Woodmagazine.com40
Connection Serviceability• Moisture Effects
%& �������� �� ��������$���'&
������( #
41
40
41
Copyright © 2015 American Wood Council. All rights reserved. 21
Wet Service Factor, CM
• Dowel-type connectors• bolts• drift pins• drift bolts• lag screws• wood screws• nails
CM 1.0 0.7 0.4* Lateral load (*CM=0.7 for D<1/4″)1.0 0.7 1.0 Withdrawal load - lag & wood screws only1.0 0.25 0.25 Withdrawal load - nails & spikes
Saturated
19% MC
Dryfabrication MCin-service MC
42
Wet Service Factor, CM
CM 0.4 Lateral load (D>1/4″)
CM = 1.0 if:1 fastener
2+ fasteners
split splice plates
Saturated
19% MC
Dry
fabrication MCin-service MC Table 11.3.3 footnote 2
43
42
43
Copyright © 2015 American Wood Council. All rights reserved. 22
Beam to Column
• Full-depth side plates• may cause splitting• wood shrinkage
44
Beam to Column
• Smaller side plates• transmit force• allow wood movement
45
44
45
Copyright © 2015 American Wood Council. All rights reserved. 23
Beam to Column
• Problem• shrinkage• tension perp
46
Beam to Wall
• Solution• bolts near bottom• minimizes effect of
shrinkage
Slotted hardware
47
46
47
Copyright © 2015 American Wood Council. All rights reserved. 24
• Beam on Shelf• prevent contact with
concrete• provide lateral
resistance and uplift
• Avoid contact with cementitious materials
Connection Serviceability
48
Beam to Concrete
• Beam on Wall• prevent contact with
concrete• provide lateral
resistance and uplift• slotted to allow
longitudinal movement• typical for sloped beam
49
48
49
Copyright © 2015 American Wood Council. All rights reserved. 25
Beam to Masonry
• Application
Need 1/2” air gap between wood and masonry
• Application
50
Column to Base
• Problem• no weep holes in closed
shoe• moisture entrapped• decay can result
51
50
51
Copyright © 2015 American Wood Council. All rights reserved. 26
Column to Base
• Angle brackets• anchor bolts in brackets
52
Hidden Column Base
• Floor slab poured over connection
• will cause decay• not recommended
53
52
53
Copyright © 2015 American Wood Council. All rights reserved. 27
Column to Base
• Floor slab poured below connection
54
Polling Question3. Proper detailing of wood members and
connections exposed to the exterior environment include:
a) Re‐directing the water flow around the connection.
b) Separating wood from concrete and masonry
c) Protecting the end grain
d) Incorporating weep holes
e) All of the above
55
54
55
Copyright © 2015 American Wood Council. All rights reserved. 28
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
56
Mechanical Connectors
57
56
57
Copyright © 2015 American Wood Council. All rights reserved. 29
Traditional Connectors
• All-wood solution• time tested• practical• extreme efficiencies
available with computer numeric control (CNC) machining
www.tfguild.orgwww.timberframe.org
58
• )��������*%++�����• ,������� ��� #� �������� ������#����-#.#/� ��������������• � ������0����• ��� ��������
• ��� ���1��� ��2�3��� !!!������� ���
Traditional Connectors
����455!!!������� ���5 !��� �5�16# % �+%+ !��� #� � �������� �
59
58
59
Copyright © 2015 American Wood Council. All rights reserved. 30
Traditional Connectors
• Wood dowel connection design technology now available
Schmidt, R.J. (2006): Timber Pegs – Considerations for Mortise and Tenon Joint Design, Structure Magazine, March 2006, NCSEA, 13(3):44-47. http://www.structuremag.org/wp-content/uploads/2014/09/SF-Timber-Pegs-March-061.pdf 60
•Common Fasteners• Nails • Staples • Wood Screws• Metal plate
connectors• Lag screws • Bolts
Mechanical Connectors
61
60
61
Copyright © 2015 American Wood Council. All rights reserved. 31
Typical Panel Connectors
62
Typical Panel Connectors
63Resource: Simpson Strong‐Tie
62
63
Copyright © 2015 American Wood Council. All rights reserved. 32
Typical Panel Connectors
64
• Included in U.S. design literature
Evaluation Reports (ER) are developed for proprietary products
Fastener Values
Fastener Type Reference
Bolts NDS or ER
Lag Screws NDS or ER
Wood Screws NDS or ER
Nails & Spikes NDS or ER
Split Ring Connectors NDS
Shear Plate Connectors NDS
Drift Bolts & Drift Pins NDS
Metal Plate Connectors ER
Hangers & Framing Anchors
ER
Staples ER
65
64
65
Copyright © 2015 American Wood Council. All rights reserved. 33
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
66
Governing Codes for Wood Design
2015 NDS referenced in 2015 IBC
67
66
67
Copyright © 2015 American Wood Council. All rights reserved. 34
ANSI Accreditation
• AWC –ANSI-accredited standards developer• Consensus Body
• Wood Design Standards Committee
68
2015 NDS Chapter Reorganization
69
2012 NDS
• 1-3 General
• 4-9 Products
• 10-13 Connections
• 14 Shear Walls & Diaphragms
• 15 Special Loading
• 16 Fire
2015 NDS
• 1-3 General
• 4-10 Products +CLT
• 11-14 Connections
• Shear Walls & Diaphragms
• 15 Special Loading
• 16 Fire
68
69
Copyright © 2015 American Wood Council. All rights reserved. 35
NDS Chapter 11 – Mechanical Connections• ASD and LRFD accommodated through Table 11.3.1• Dowel fasteners• Split ring/shear plate• Timber rivets• Spike grids
.�!���������� ���������+%7.8�9 70
NDS Dowel-fastener Connections• 2015 NDS Chapter 12 (New location)• Can be used for any dowel-shaped fastener• Includes lateral and withdrawal provisions
• Bolts• Lag screws• Wood screws• Nails• Spikes• Drift bolts• Drift pins
71
70
71
Copyright © 2015 American Wood Council. All rights reserved. 36
Dowel-fastener withdrawal• Withdrawal calculated based on fastener penetration
• W value is per inch of fastener penetration• Threaded fasteners use thread penetration
• Lag screws• W = 1800 G3/2 D¾
• Wood screws• W = 2850 G2 D
• Nails (smooth shank)• W = 1380 G5/2 D .!��� ��!������ ��������!� ���
�����! ����!�9
72
Yield Modes
MODE I•bearing-dominated yield of wood fibers
MODE II•pivoting of fastener with localized crushing of wood fibers
73
72
73
Copyright © 2015 American Wood Council. All rights reserved. 37
Yield Modes
MODE III•fastener yield in bending at one plastic hinge and bearing –dominated yield of wood fibersMODE IV•fastener yield in bending at two plastic hinges and bearing –dominated yield of wood fibers
74
Dowel Bearing Strength
75
74
75
Copyright © 2015 American Wood Council. All rights reserved. 38
Fastener Bending Yield Test
Center-Point Bending Test
Load
76
Fastener Bending Yield Strength
77
76
77
Copyright © 2015 American Wood Council. All rights reserved. 39
Yield Limit Equations
•4 Modes of failure•6 Yield equations•Single & double shear
)!���:��� ;<=$����>#�������#�������
78
Yield Limit Equations
79
78
79
Copyright © 2015 American Wood Council. All rights reserved. 40
Yield Limit Equations
?�������� ���@%���������9
80
Spacing, End, & Edge Distance
81
80
81
Copyright © 2015 American Wood Council. All rights reserved. 41
Spacing, End, & Edge Distance
82
Spacing, End, & Edge Distance
83
82
83
Copyright © 2015 American Wood Council. All rights reserved. 42
• Unless special detailing is provided to accommodate cross-grain shrinkage of the wood member.
Spacing, End, & Edge Distance
84
Polling Question4. The NDS Yield Limit Equations are used to
determine:
a) Lateral capacity of connections
b) Withdrawal capacity of connections
c) Lateral and withdrawal capacities of connections
d) None of the above
85
84
85
Copyright © 2015 American Wood Council. All rights reserved. 43
NDS Appendix E• Appendix E – Local Stresses in Fastener Groups (Non-
mandatory)• Groups of closely spaced fasteners loaded parallel to grain
• Net Section Tension Capacity
• Row Tear-Out Capacity
• Group Tear-Out Capacity
• Example problems• Staggered rows of bolts
• Single row of bolts
• Row of split rings
86
Chapter 12-Dowels
87
86
87
Copyright © 2015 American Wood Council. All rights reserved. 44
Chapter 12-Dowels
88
Dowel DiametersThreaded length < lm/4 l�
Dia. Fastener = D
Dia. Fastener = D
Threaded length < lm/4 l�
89
88
89
Copyright © 2015 American Wood Council. All rights reserved. 45
Dowel Diameters
Dia. Fastener = Dr
• NDS Chapter 12 Tables use Dr for lateral yield equations• Assumes shear plane passes through threads
l�
90
Chapter 12 – Dowel-type Fasteners
91
New
90
91
Copyright © 2015 American Wood Council. All rights reserved. 46
Chapter 12 – Dowel-type Fasteners
92
New
Chapter 12 – Dowel-type Fasteners
93
New
92
93
Copyright © 2015 American Wood Council. All rights reserved. 47
Chapter 12 – Dowel-type Fasteners
94
New
Non-uniform for CLT
• Adjust lm or ls to compensate for orthogonal grain orientations in adjacent layers
• Parallel to grain: Fe/FeǁExample: ½” bolt in southern pine 3-ply CLT
with 1-½” laminationslm = t1ǁ + t2 + t3ǁ = 3(1.5) = 4.5”lm-adj = t1ǁ + t2(Fe/Feǁ) + t3ǁ
=1.5 +1.5(3650/6150) +1.5 = 3.9”
95
Chapter 12 – Dowel-type Fasteners
94
95
Copyright © 2015 American Wood Council. All rights reserved. 48
96
Chapter 12 – Dowel-type Fasteners
New
Chapter 12 – Dowel-type Fasteners
• Lateral – any end grain• D<1/4” Ceg=0.67
• Lateral – any CLT edge• D>1/4” Ceg=0.67
97
New
96
97
Copyright © 2015 American Wood Council. All rights reserved. 49
Technical Report 12
• Background and derivation of the mechanics-based approach for calculating lateral connection capacity used in the NDS
• Provides additional flexibility and broader applicability to the NDS provisions
• Connections with gaps between members• Connecting wood to members with hollow cross sections
http://www.awc.org/codes-standards/publications98
Technical Report 12
99
98
99
Copyright © 2015 American Wood Council. All rights reserved. 50
Technical Report 12
100
Technical Report 12
101
100
101
Copyright © 2015 American Wood Council. All rights reserved. 51
Technical Report 12•Allows for evaluation of connections with gaps between connected members
102
Technical Report 12• Tapered tip fasteners
• NDS 12.5.3 defines “E” as length of tapered tip• Lag screws – E defined in Appendix L
• Wood screws, nails – E assumed to be 2D
• Tapered tip does not count towards bearing length (Lm) in TR12 Tapered tip equations.
103
102
103
Copyright © 2015 American Wood Council. All rights reserved. 52
Technical Report 12• Tapered tip equations
• Mode Im
• Mode Is
• Mode II
• Mode IIIm
• Mode IIIs
• Mode IV
�@%���!�.8�����A�� ��������B%& ����������� ��
����A��� � �������9
104
Technical Report 12
• TR12 presents mechanics-based equations • Gives same results as NDS energy-based approach
• Equations in TR12 calculate P, must be divided by Rd (NDS Table 12.3.1B) to convert to NDS Z basis
• TR12 Appendix being released later in 2015
105
104
105
Copyright © 2015 American Wood Council. All rights reserved. 53
Technical Report 12 Appendix• New for 2015!
• Contains additional data for TR12 equation inputs
• Dowel bearing values for:• Wood• Steel• Concrete• Stainless steel• Aluminum
• Dowel bending values for fastener materials: • Steel and stainless steel bolts
and lag screws• Low-to-medium carbon steel
nails• Hardened steel nails (including
post-frame ring-shank)106
Example Problem #1
• Calculate W for ¼” diameter, 2.5” long lag screw connecting 2-2x SYP (G = 0.55) members
• W = 1800 G3/2 D¾ = 260 lbs/in (calculate or NDS Table 12.2A)• Calculate penetration into main member for withdrawal capacity
• NDS Appendix L gives lag screw dimensions• Length of unthreaded section = ¾”
• Length of threaded section (including tip) = 1¾”
• Length of threaded section (excluding tip) = 119/32”
• p = screw length – length of side member – length of tip
• p = 2.5” – 1.5” – (1¾” - 119/32”) = 0.84” of penetration
• Unadjusted capacity = W*p = (260 lbs/in * 0.84 in) = 219 lbs• Apply adjustment factors per Table 11.3.1 to get adjusted W’
107
106
107
Copyright © 2015 American Wood Council. All rights reserved. 54
Example Problem #2 • Calculate unadjusted Z for ½” diameter bolt connecting two
2x DF-L (G = 0.5) members with a 1” gap between them• Both members loaded parallel to grain (K = 1)
• D = 0.5”
• Fell= 5600 psi (NDS Table 12.3.3); qs = qm = Fell
* D = 5600 psi * 0.5” = 2800 lb/in
• Ls = Lm = 1.5”
• Fyb = 45,000 psi
• g = 1”
108
Example Problem #2 • Calculate unadjusted Z for ½” diameter bolt connecting two
2x DF-L (G = 0.5) members with a 1” gap between them• Mm = Ms = (FbD3)/6 = (45,000 psi)*(0.5”^3)/6 = 937.5 lb-in
• Substituting values into TR12 equations yields P values• Divide P values by Rd to obtain Z
Mode P (lbs) Rd Z (lbs)
Im 4200 4K = 4 1050Is 4200 4K = 4 1050II 1163 3.6K= 3.6 323
IIIm 1211 3.2K = 3.2 378IIIs 1211 3.2K = 3.2 378IV 1285 3.2K = 3.2 402
<>C�C��� 109
108
109
Copyright © 2015 American Wood Council. All rights reserved. 55
Example Problem #3
• Compare lateral Z values for single shear nail connection at 6D, 8D, 10D, and 12D penetration using TR12 tapered tip equations
• 8d common nail D = 0.131”, tapered tip length, E = 2D = 0.262” • Main member Fem = 4,700 psi (loaded parallel to grain); ASTM
A653, Grade 33 steel side member, thickness = 0.06”, Fes = 61,850 psi
• Lm = p (penetration into main member); Ls = 0.06” (side member thickness)
Penetration Depth (p) Z (lbs) Controlling
mode12D (1.57") 97 IIIs10D (1.31") 97 IIIs8D (1.05") 97 IIIs6D (0.79") 79 II
110
Example Problem #3
• Compare Z values for single shear nail connection at 6D, 8D, 10D, and 12D penetration using NDS Lm assumption for tapered tip
• 8d common nail D = 0.131”, tapered tip length, E = 2D = 0.262” • Main member Fem = 4,700 psi (loaded parallel to grain); ASTM
A653, Grade 33 steel side member, thickness = 0.06”, Fes = 61,850 psi
• Lm = p – E/2 (NDS assumption) ; Ls = 0.06” (side member thickness)
Penetration Depth (p) Z (lbs) Controlling
mode12D (1.57") 97 IIIs10D (1.31") 97 IIIs8D (1.05") 97 IIIs6D (0.79") 78 II
111
110
111
Copyright © 2015 American Wood Council. All rights reserved. 56
Polling Question7� ���������@����%���$� ���DDDDDDDDD
������������������������������������������� � ����������
a) Mechanics‐based
b) Energy‐based
c) Hybrid model
d) None of the above
112
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
113
112
113
Copyright © 2015 American Wood Council. All rights reserved. 57
http://www2.wwpa.org/TECHGUIDEPAGES/DesignSoftware/tabid/859/Default.aspx
•WWPA Lumber Design Suite
• Beams and Joists• Post and Studs• Wood to Wood
Shear Connections (nails, bolts, wood screws and lag screws)
Software Solutions Exist
114
Example Problem – Connections Calculator • AWC Connections Calculator
• Can calculate lateral and withdrawal capacities• http://awc.org/codes-standards/calculators-software/connectioncalc
Calculators
115
114
115
Copyright © 2015 American Wood Council. All rights reserved. 58
Example Problem – Connections Calculator
<2
116
Outline
• Wood connection design philosophy
• Connection behavior• Serviceability challenges• Connection hardware and
fastening systems• Connection techniques • Design software• Where to get more
information
117
116
117
Copyright © 2015 American Wood Council. All rights reserved. 59
• 2012 NDS
More info???
118
http://www.awc.org/pdf/2012ASD-LRFD_Manual_WEB.pdf
• M4.4 Special Design Considerations• Mechanical Connections• Dowel-Type Fasteners• Split Ring and Shear Plates Connectors• Timber Rivets
More info???
119
118
119
Copyright © 2015 American Wood Council. All rights reserved. 60
More info???
2015
120
• Technical papers on Timber rivets: http://www.awc.org/helpoutreach/faq/faqFiles/Timber_rivets.html
• Timber rivets in structural composite lumber• Simplified analysis of timber rivet connections • Timber rivet connections in U.S. domestic species• Timber Rivets-Structure Magazine• Seismic Behavior of Timber Rivets in Wood Construction• Seismic Performance of Riveted Connections in Heavy
Timber Construction• Timber rivet suppliers
More info???
121
120
121
Copyright © 2015 American Wood Council. All rights reserved. 61
More info???• Load-carrying behavior of steel-to-timber dowel connections:
http://timber.ce.wsu.edu/Resources/papers/2-4-1.pdf• New Concealed Connectors Bring More Options for Timber
Structures http://www.structuremag.org/Archives/2007-1/p42-43D-Insights-ConcealedConnectorsJan07.pdf
122
Take Home Messages...• Transfer loads in compression / bearing whenever possible• Allow for dimensional changes in the wood due to potential in-
service moisture cycling• Avoid the use of details which induce tension perp stresses in
the wood• Avoid moisture entrapment in connections• Separate wood from direct contact with masonry or concrete• Avoid eccentricity in joint details• Minimize exposure of end grain
123
122
123
Copyright © 2015 American Wood Council. All rights reserved. 62
Connections
…and you thought connecting wood was complicated!
124
125
124
125
Copyright © 2015 American Wood Council. All rights reserved. 63
• This concludes The American Institute of Architects Continuing Education Systems Course
Questions?
126
American Wood [email protected]
126