Is 4x really minimum wood post size? 1

[SacreBleu]

According to a plans review for a multi-family, 3-story wood framed apartment building structure, the "overzealous" 3rd-party plans check engineer (bless his soul) made this comment (bear in mind that the definition of "column" and "post" includes compression members located within wood stud bearing walls):

"Columns and posts souuld not be less than 4x nominal. Review and clarify. Reference IBC Section 1603.1"

Now correct me if I am wrong - what nonsense. If (2)-2x built-up post calculates adequately, I do not see anything in the "Incomprehensible" Building Code otherwise.

 

[whyun]

In 1997 UBC (not IBC yet here) Table 23-II-I-1 footnote 3, it talks about using a nominal 3x member at sills and studs receiving abutting panels where forces exceeds 350 plf. This is for seismic zones 3 and 4 only, and I'm not sure if it applies in your area.

Being in Zone 4 mostly, only time I mandatorily (?) provide a 4x minimum post is at all shear wall boundaries. I can't recall a code section but engineers out here just do this as a standard. For non seismic studs at doors or windows may be double 2x.

 

[SacreBleu]

whyun,
Thanks, but we don't use the California criteria here. It is very low seismic. We typically use built-up 2x for posts (that was the original plans check comment - no specific reference to end of shear wall. If load is too high, we use 4x, 6x etc.
I did a few custom homes for California years ago. I remember the requirement to use 4x posts at hold downs; (2)- 2x was not allowed.

 

[whyun]

Yes. 4x at all holdown posts as a minimum.

When you say built-up 2x posts, can you be specific as to what load its carrying? In case of exterior condition double studs at openings may have gravity loads as well as wind reaction at the headers (thus 2-2x may not work at long header conditions). I was not sure what situation warranted your checker to require 4x.

Good weekend...

 

[SacreBleu]

The exterior headers are designed with "trimmers", or "jacks" as you may call them, supporting the header 9bottom of header or beam).
The "king studs" are then run up to the double top plate of wall.
Thus, the trimmers do not carry wind load. The number of kings are calculated to carry the wind bending.

 

[crossframe]

PSlem,

I've always preferred "The Optimist sees the glass as half full. The Pessimist sees the glass as half empty. The Engineer sees that the glass has a Safety Factor of two."

 

[tweedledee]

I once had a plan checker "Engineer" include this comment to my drawings. "How do you expect the load from a 6X6 steel tube column to distribute out to a 6ftx6ft footing?".
So I replied, and informed him of a new building material in common use these days,.. STEEL REINFORCING BARS!

 

[PSlem]

One reason for spec'ing a solid post. If you used a built up post in a shear wall, you would need to repeat your edge nailing pattern on both studs. Otherwise one gets all the load.

The optimist sees the glass as half full. The pessimist sees the glass as half empty. The engineer see the glass as too big.