Accidental eccentricty in design of wood posts or load-brg studs?

[AELLC]

I saw this as a footnote in some Glulam Column (GLC) load tables - is the actually a reqd Code item?

They had it as 1/6 post dimension, check for x-x and y-y direction, whichever governs.

 

[CBSE]

To my knowledge it isn't a code requirement. However, I always add in a little bit to be on the safe side anyways. Pretty much anytime you are framing (2) or more beams onto a post you will have some eccentricity due to the difference in loads from each beam.

 

[AELLC]

Thanks CBSE.

I suspected this was a Glulam Advisory Council or whatever worry because the GLC properties are so high, you end up with a post that looks much too small.

 

[CBSE]

I believe the 1/6 number you are referring to is a number used in the allowable axial load tables for columns that was published by the APA. The 1/6 column dimension is a conservative estimate based on the fact that a wood column is rarely loaded 100% concentrically.

 

[AELLC]

So, the APA used it and it is not strictly Code requirement.

 

[CBSE]

Yes, that is what I believe happened so that they could develop there "General" axial load capacities for various columns. I don't like it because all loading is different and all eccentricities are different. I use a simple spreadsheet to calculate my eccentricities based on bearing width of beam on post and loads and sum moments about the center line of the column and then get my eccentricity that way...pretty simple and very quick to do when dealing with really large beams and small ones too. The tricky part is when you start getting bi-axial eccentricity.

 

[AELLC]

One simple scenario for me would be to specify a 6x6 post under the heavy beam and then (2)-2x6 post right next to the 6x6 for the light beam.

Besides, builders like that much better than a single 6x8 post.