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RE: Wood "Nailed" Moment Connection

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I analyzed my case as a two-hinged arch for dead, live, snow and wind as appropriate (moment, axial, and shear for unbalanced load).  Since this was just a roof joist, the loads weren’t tremendous.  I don’t remember what fasteners I used (ie bolts or nails), but I assumed a fastener layout and checked that against allowable capacity.  Then I checked the plywood stresses.  The member stresses also must be checked (reduced section at bolts).  Unbalanced loading could produce different loading patterns at the splice point.  Your situation is a lot shallower, so it feels a lot more like a beam to me than an arch.  I have to admit that I would personally be a bit uncomfortable trying to create a splice in wood in a relatively flat member, at midspan, considering potential for deformations.  I definitely would be very conservative if no other choice.

 

Eric

 

-----Original Message-----
From: Rand Holtham, P.E., Sigma Engineers [mailto:rand(--nospam--at)sigmaengineers.com]
Sent:
Monday, May 19, 2003 5:42 PM
To: seaint(--nospam--at)seaint.org
Subject: Wood "Nailed" Moment Connection

 

Eric, Did you design the plywood splices for the max moment? If so how does the design proceedure go?

 

 

There is a reference to moment connections in the "Wood Engineering and
Construction Handbook" by Faherty and Williamson (McGraw-Hill).  They =
have
two different cases, a multiple steel plate connection and a rigid steel
plate connection.  The single rigid plate can cause splitting of wood =
due to
restrained shrinkage.  The multiple plate anchorage minimizes that =
problem.
For similar conditions to yours, but a steeper slope, I've used plywood
gussets at the ridge (no ceiling in the space, so no collar ties were
available) in residential construction. =20

=20

Eric

=20