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Replacing wood columns with steel pipe
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Posted by: Mike Morocco

11/09/2009, 13:23:15

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Presently I have two Douglas Fir columns supporting a 24ft span of Douglas Fir beam and would like to replace the two wood columns with one steel column. The existing wood columns (lxwxh) are 5"x6"x90.25" and 4"x8"x89.25" and are located at 66" and 177" along the 288" span. There are no visible signs of sheering. The approximate allowable load/square inch are 1,735 and 1,086, respectively. Originally, there was one 6"x6"x90.25" wood column located at 144" doing the job; the approximate allowable load/square inch was 2,443. I don't know why the original column was replaced but rotting is a likely suspect since the location is in a basement that saw frequent flooding years ago. Flooding is no longer an issue.

I want to replace the two wood columns with one steel pipe column but as a framing contractor, I've not much experience with steel pipe columns. I would welcome any suggestions of what to order from my local machine shop. I need a plate at top and bottom of the column for fastening but I don't know what to specify for the column itself.








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: Replacing wood columns with steel pipe
: Replacing wood columns with steel pipe -- Mike Morocco Post Reply Top of thread Engineering Forum
Posted by: zekeman

11/09/2009, 16:43:52

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"The approximate allowable load/square inch are 1,735 and 1,086, respectively. Originally, there was one 6"x6"x90.25" wood column located at 144" doing the job; the approximate allowable load/square inch was 2,443. I don't know why the original column was replaced but rotting is a likely suspect since the location is in a basement that saw frequent flooding years ago. Flooding is no longer an issue......"
I don't understand this. Where did you get this? And,do you mean that the allowed compressive stress in the two original columns were 1735 and 1085 psi and what does 2443psi mean and where does that come from ?
.Without data on the total floor loading you cannot get a definitive answer. Also, keep in mind that the reason for 2 columns may have been to reduce the stress and deflection in the main beam.Building code should give the allowable deflection, shear loading and stress in the that beam.
The steel column you propose is the easy part.







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: Replacing wood columns with steel pipe -- Mike Morocco Post Reply Top of thread Engineering Forum
Posted by: Marky

11/09/2009, 13:50:54

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Hi and welcome to the forum....Did you know that you can buy these at your home improvement store?

Tiger Brand 8 Ft. 4 In. Super "S" Series Jack Post








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: : Replacing wood columns with steel pipe -- Marky Post Reply Top of thread Engineering Forum
Posted by: Mike Morocco

11/22/2009, 01:51:12

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Thanks for the suggestion.
I have resolved the problem. After discussing the need with the wizard at the local welding shop, we settled on a 4" diameter pipe with 3/8" plate steel foot and header. It is doing an excellent job and is tremendously less obstructive than the two 6x6 fir posts! I still haven't learned the support load limitations of the 1/4" walled pipe but it appears to be holding and I can stop worrying about the sheering of the wood columns.








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: : : Replacing wood columns with steel pipe -- Mike Morocco Post Reply Top of thread Engineering Forum
Posted by: Marky

11/22/2009, 10:12:51

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Hi MIke....Glad it worked out for you. Thank you for checking back with us and giving us an update.

Happy Holidays!!!








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