Lally Column


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  Thanks in advance,                                                                                                                                                                                                                                                  I                 I am using Chief's Adjustable Lally Column under my Girder. Problem is that the adjustable end is down and should be up. Is there a way to flip this or does anyone have one that is the correct way?

 

               Thanks, Ken  

Cook #8_Feb.2,2023.jpg

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24 minutes ago, architect said:

Codes require the adjustable part to be welded or cover the threads with concrete after installation.

Down is the correct orientation with the threads below the slab. If you were jacking/leveling for a reno would be a different?

 

Eric

Interesting do you have the code reference for that?

 

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Ryan,
 
Looks like I am a little weak on the "code required" part based only on :
IRC R407.3 Structural Requirements: The columns shall be restrained to prevent lateral displacement at the bottom end.
 
But manufacturer's instructions require the screw be welded or encased in concrete, so I guess that becomes a requirement.
 
Eric
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I know...It is sad that I am looking this stuff up on a Saturday, but inquiring minds want to know.

 

This is from an adjustable column manufacturers ICC-ES code evaluation Installation instructions:

 

4.1. The Marshall Extend-O-Column must be installed with the adjustable screw mechanism on the bottom. The entire adjustment mechanism, including the entire collar nut, shall be encased in minimum 3500 psi (24.1 MPa) concrete

 

"Zip" Column report says you can "damage one thread 1-1/2" for 1/2 its depth" and must be installed with threads must be at the bottom.

 

That makes it part of the code if you a going to use it.

 

Eric

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2 hours ago, architect said:

4.1. The Marshall Extend-O-Column must be installed with the adjustable screw mechanism on the bottom. The entire adjustment mechanism, including the entire collar nut, shall be encased in minimum 3500 psi (24.1 MPa) concrete

This makes no sense it the columns is supposed to function in the future to adjust for settlement.

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We use the concrete-filled ones you cut to the height you need.  They come with a base plate that anchors to the slab, and we use the Simpson LCC caps.

 

If a builder told me I had a lally upside down in a 3D render, I'd say my bad, that render will never make it to the con docs, it was for illustration only, and leave it as-is.  The lallys, and their hardware, are annotated with callouts on the structural floor plans.

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On 2/11/2023 at 11:48 AM, Joe_Carrick said:

This makes no sense it the columns is supposed to function in the future to adjust for settlement.

 

I don't believe that planning for future adjustment is the intended use of a field-height adjustable column. The adjustment range aids in erection, ensures the full bearing of the structure on the cap, and allows for leveling the floor. I agree with Eric @architectthat most column manufacturers require the adjustment screw to be disabled after final adjustment. Here is the language from the ICC ESR reports for two widespread brands:

 

Afco: After the column has been adjusted...one screw thread must be damaged...to prevent vertical movement of the column.

Akron/Tiger: After installation, the adjustment assembly must be encased in concrete to prevent movement after installation.

 

Perhaps there are exceptions, but in my neck of the woods, you won't get an occupancy permit unless the adjustment mechanism has been disabled.

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Ahh....  I understand.

 

I was thinking more like what's required for Log Homes with Log Columns.  There we use a jacking plate under the Columns to be adjusted as the Log Bearing Walls shrink.  Typically those are provided to allow the Columns to be lowered to match how much the walls shrink in height.  If I was using a Lally Column within a Log Home I would not want to disable the adjustment screws.

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