Connection Solutions for Wood-frame Structures

Presented by: John Buddy Showalter, P.E. Vice President, Technology Transfer

The Wood Products Council is a Registered Provider with

. Credit(s) earned on completion of this program 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 program 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 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.

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.

© American Wood Council 2012

Learning Objectives

At the end of this program, participants will be knowledgeable of:

1.  Identify basic wood material properties and learn how to avoid splits, notching, and checking in connection solutions.

2.  Recommend fastening guidelines for wood-to-steel, wood-to-concrete, and wood-to-wood connections.

3.  Describe effects of moisture on wood connections and implement proper flashing to avoid problems.

4.  Identify proper fastener selection in size, scope, and pattern.

 

 

  

 

 

  

  

   

    

initiators: •  notches •  large diameter fasteners •  hanging loads

 

 

Split

 Full wrap sling option

Split

 

 

   

  

 

Split

 

 

 

  

 

 

  

 

 

 

   

   

  

  

Load

Displacement

high strength, poor ductility

good strength, good ductility

low strength, good ductility

   

   

  

 

No end caps or flashing

 

end caps and flashing

 

Moisture trap - No weep holes

Saturated

19% MC

Dry 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 only 1.0 0.25 0.25 Withdrawal load - nails & spikes

•  Dowel-type connectors •  bolts •  drift pins •  drift bolts •  lag screws •  wood screws •  nails

fabrication MC in-service MC

Saturated

19% MC

Dry CM 0.4 Lateral load (D>1/4″)

fabrication MC in-service MC

CM = 1.0 if:

1 fastener

2+ fasteners

split splice plates

 

 

 

 

 

 

 

 

Slotted hardware

 

 

 

 

 

 

Need 1/2 air gap between wood and masonry

 

 

 

 

  

 

 

 

 

 

   

   

  

  

 

www.tfguild.org www.timberframe.org Schmidt, R.J. (2006): Timber Pegs – Considerations for Mortise and Tenon

Joint Design, Structure Magazine, March 2006, NCSEA, 13(3):44-47.

 

  

 

Fastener Values

Included in U.S. design literature Fastener Type Reference Bolts NDS or NER Lag Screws NDS or NER Wood Screws NDS or NER Nails & Spikes NDS or NER Split Ring Connectors NDS Shear Plate Connectors NDS Drift Bolts & Drift Pins NDS Metal Plate Connectors NER Hangers & Framing Anchors NER Staples NER

National Evaluation Reports (NER) are developed for proprietary products

Center-Point Bending Test

Load

• 6 Yield Modes • Single & double shear • Wood-to-wood • Wood-to-Steel • Wood-to-Concrete

I

II

III

IV

Nail Types and Designations

Nail types described in Appendix L

Nail Types and Designations

Nail capacity tables in 2005 NDS

NDS 11.3.4 The length of dowel bearing shall not include the length of the tapered tip of a fastener for fastener penetration lengths less than 10D.

  

–  l–  l

   

 

 

shea

r pla

ne

Dr

 

use Dr

shear plane

 

Because the induced maximum moment can occur in the threads if the shear plane is not located sufficiently into the shank away from the threads

    

  ⊥

  ⊥

  ⊥

 

 

 

 

Group Action Factor, Cg

•  Equation method

where:

( )( )[ ] ⎥⎦

⎤⎢⎣

⎡−

+⎥⎦

⎤⎢⎣

⎡

+−++

−=

mR

mmmRnmmC EA

nnEA

n

g 11

111)1(

2

2

ss

mm

mm

ssEA AE

AEAEAER or oflessor the=

12 −−= uum

⎥⎦

⎤⎢⎣

⎡++=

ssmm AEAEsu 112

1 γ

Group Action Factor, Cg

Group Action Factor , Cg

Not applicable here - loads acting along the length of the member are unit loads

Anchor Bolts and Washers as required

Bottom Plate

•  Appendix E - Local Stresses in Fastener Groups 

 

 

 

 

 

•  Appendix E NDS Expressions –  Net tension:

–  Row tear-out:

nettNT AFZ '' =

∑=

=

=

row

i

i

n

iRTRT

viRT

ZZ

tsFnZ

1

''

min''

•  Appendix E NDS Expressions –  Group tear-out

•  Note: spacing between outer rows of fasteners paralleling the member on a single splice plate < 5″

netgrouptbottomRTtopRT

GT AFZZZ −

−− ++= '''

'22

 

 

 

 

Chapter 13 – Timber Rivets Rivets •  Steel AISI 1035 •  Rockwell Hardness C32-39 •  Fu = 145 ksi •  Hot-dipped galvanized

Plates •  Steel ASTM A36 •  Hot-dipped galvanized if in

wet service

  

  

  

 

  

   

   

  

 

  

 

 

  

 

 

 

 

   

   

  

  

  

 

Hidden kerf plates

 

   

     

   

  

Connections design software

   

   

  

• • 

 

 

 

  

  

?

This concludes The American Institute of Architects Continuing

Education Systems Course

www.awc.org

info@awc.org

Questions?