Wood Column Splices 1

[kmart30]

Can you analyze this post as three separate posts or 1 post with 2 spices? Connections would be toe-nails to beams/plates and straps on each side for uplift resistance. Post is not at a gable end and plates are good for compression. I have been challenged by a colleague with a question on "stability" of this wood post on how it is currently drawn. I have a paper I pulled from a previous post on here for steel columns that concluded "splices do not have a negative influence on the stability of columns even when tensile stresses are present at the splice location". Obviously wood and steel are different but do I have an argument here?

Load is around 3kips on a 4x6 post.
Top Column = 4'
Middle Post = 8'
Bottom in Crawlspace = 3'

 

[msquared48]

If there is a floor diaphargm at each of the two splice points that would provide lateral stability brace pints, then you can analyze this as three individual columns.

With no lateral brace points present, then one single column.

Mike McCann, PE, SE (WA)

 

[DETstru]

If you have lateral support to brace the post in all directions you can just analyze it as 3 separate posts.

 

[txeng91]

You will have lateral support at the floor level. The question is if you have lateral support at the ceiling level. I’m guessing you have a flat ceiling at the plate line coming into at least one side of the wall. Gyp board can act as a diaphragm (i.e. a lateral support) if attached properly. At a minimum I would provide blocking running in an out of the page between the column and adjacent framing members at the floor and ceiling levels to properly develop any buckling forces into the diaphragms. You could also run diagonal braces from the base of the column at the ceiling plate up to the roof that is sheathed with plywood, which is a much more dependable diaphragm.

 

[KootK]

I agree with everybody else. As long as the top plate of that wall is restrained somehow, you should be good to go as three separate columns. I don't like the one column spliced twice concept though. For that, I'd like to see more convincing connections and perhaps some research to pack it up. I'd argue that steel column connection afford a good deal more nominal moment capacity and flexural stiffness.

Any chance I could take a boo at that steel splice paper that you referenced? I've always been interested in that myself.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[kmart30]

Here it is Kootk....

 

[KootK]

Thanks kmart. Very gracious of you to circle back and share that.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.