Wood Column for Steel Column 1

[bowma73]

I am currently working on a project where the contractor wants to replace the steel columns with wodden ones. Has anyone worked with or seen a wood column large enough to handle a load of 50 kips with a length of 14 feet. I do not believe a resonably sized wood column for this situation exist but any advice or information would be helpful.
Thanks

 

[geoffdale]

To get something with a decent size, I would think you would be into composite (PSL or LVL) or like a 10x10 Douglas Fir.

 

[Lion06]

Is that 50 kips a service load or ultimate load. A lot of it will depend on column stability because that is really the largest reduction factor for wood column design. 50 kips is a very large load for a wood column.
Making some assumptions (it is service load, Cd=1.0 for LL, interior, no temp concerns, and only braced at ends (pinned)) and using Doug-fir larch No.1, I am getting that you need a pretty healthy section (10x10)

 

[bowma73]

It will be an interior column, pinned on both ends with the 50 kips being the ultimate load

 

[COEngineeer]

50 ultimate? Then I think it is doable unless they want to hide it in a wall.

Never, but never question engineer's judgement

 

[bowma73]

So 10x10 douglas fir would be acceptable?

 

[bowma73]

Also, can anyone give me a website that has different sizes and types of wood columns and what load capacities they can handle? Thanks

 

[Lion06]

a 10x10 doug-fir No.1 would be a bit overkill for 50 Kip ultimate load. You can definitely come down from that. That was sized for a service load.
Look in the NDS supplement for capacities. I think the suplement is available online for free.

 

[Lion06]

http://www.awc.org/Publications/download.html

Go to this page and scroll down to "Design Standard Supplements and Commentaries".
There you can download the 2005 NDS supplement for free.

 

[MiketheEngineer]

I show that a 10 x 10 #1 DF-L would probably work.

However - I would worry about long term creep, swelling and shrinkage, etc.

If the rest of the columns are steel - stay with steel. If they are wood - then maybe...but that column might move differently than the existing building.

 

[RARWOOD]

You should be able to down load some column tables from the AITC web site.

 

[RareBugTX]

It is definitely doable, a few years ago, I investigated a 12"x12" sawn lumber column, and I recall being 13' high. My column capacity neighbored the 80 kips which was more than enough for my loads. I recommend you the "Timber Solutions Manual" by David D.Duquette P.E. it has a lot of wood column examples, but you also need the N.D.S as someone suggested.

Regards,

Rarebug, Chicago

 

[msquared48]

I would agree that a 10 X 10 DF column, and perhaps less, would be sufficient to replace the steel column if the column alone was what there was to consider.

I would pose the question though as to on what the column was to bear, and what was to bear on the column. Unless it is rough cut, a 10 X 10 has a gross area of around 85.6 square inches or so. For a load of 50 kips, this gives a bearing stress of 584 psi. Whatever this column supports, or is supported by, will see this load. If it is wood, there will be crushing issues if Fc perp of the wood material other than the 10X10 column is exceeded. A smaller column will produce higher end bearing stresses, a larger one less. Not a difficult problem to solve, but one not to ignore.

Mike McCann
MMC Engineering

 

[stageleft]

I hope this is not dumb, but is the replacement for aesthetic purposes?
If so, why not just clad existing steel columns with timber (recycled or otherwise if appropriate), maybe less work and expense.

 

[bill30206]

Whether in your judgment there should be 1", 1-1/2", 2", etc of axial load eccentricity accounted for should be considered. Using my spreadsheet to experiment with different sizes of DF-L SS, it appears that the size or whether anything reasonable will work at all depends heavily on the eccentricity. I didn't see eccentricity discussed in the thread.