Extend-O-Column, threads MUST be encased in concrete, WHY?

[Buelligan]

Hey guys, not sure if this has been discussed or not. Couldn't find any threads in the search.

I know these adjustable columns have been installed every which way for years. But now they are clearly labeled that the adjustable thread MUST be DOWN and encased in 3500 psi concrete. Now what I want to know is the reason for this.

1) is it for the pupose of disabling the thread (welding the thread would do this, right?)

2) is it to stablize the bottom of the column (bolting the plate would also acomplish this) or

3) is it to remove the screw from the equation so that all the weight transfer is on the COLUMN and NOT the threads.

Now when I was in school we used to roll up a sheet of paper to form columns upon which we could stack a tremendous amount of books on top of 4 of them. So in my mind the purpose is to put the ENTIRE load on the column and therefore remove ALL loads from the threads. Something about all the weight on a couple of 1/8" or less deep threads just doesn't sit right with me. By the way I was told that the threaded plug is only 3/4" deep on a 3.5' column. I called the manufacturer and he stated they just put that on the label because ICC required it but had no answer as to why. I have a job in which encasing in concrete would be difficult to do. I have the contractor going back to the engineer but wanted some other input, Thanks

Any ideas?

 

[Buelligan]

R407.3 Structural requirements.

The columns shall be restrained to prevent lateral displacement at the bottom end. Wood columns shall not be less in nominal size than 4 inches by 4 inches (102 mm by 102 mm). Steel columns shall not be less than 3-inch-diameter (76 mm) Schedule 40 pipe manufactured in accordance with ASTM A 53 Grade B or approved equivalent.

By the way this is the only reference in the IRC that I see so far. This tends to lean towards number 2 above, lateral restraint only. But if that is the case why does the label state encased in concrete when bolting the plate would secure it in place. Unless the threaded joint is only tested for vertical load and not lateral movement? Meaning they want the column restrained and not the threaded portion?

 

[Buelligan]

WOW Nothing? No opinions at all? I am stunned! You guys always have a comment even if it is a smart a#* remark LOL. So no one has seen this as an issue? I also found an ATI Evaluation Service report CCRR-0145 that clearly states under insallation that "the ENTIRE screw mechinism must be entirely ecased in 3500psi concrete."

Link to the report is here - -http://www.archtest.com/certification/Download.aspx?DocID=258&CN=cnCodeCompliance

I am even seeing these put on top of stem walls in garages to support steel beams with no way to encase them in 3500 psi concrete. I had an engineer for the cotractor just write a report that they just weld the threads, but im my opinion, based on the report, that is not acceptable RIGHT? ANYBODY?

 

[mtlogcabin]

My guess is if the bolt is not encased in the concrete it will not meet the lateral displacement requirements specifically in high seismic and wind zones since the majority of these loads are at the bottom of the columns.

 

[tmurray]

WOW Nothing? No opinions at all? I am stunned! You guys always have a comment even if it is a smart a#* remark LOL. So no one has seen this as an issue? I also found an ATI Evaluation Service report CCRR-0145 that clearly states under insallation that "the ENTIRE screw mechinism must be entirely ecased in 3500psi concrete."Link to the report is here - -http://www.archtest.com/certification/Download.aspx?DocID=258&CN=cnCodeCompliance

I am even seeing these put on top of stem walls in garages to support steel beams with no way to encase them in 3500 psi concrete. I had an engineer for the cotractor just write a report that they just weld the threads, but im my opinion, based on the report, that is not acceptable RIGHT? ANYBODY?

It would depend on the wording of the engineer's report. I'd want it clearly spelled out that this is an alternative that carries the same load as the concrete.

 

[codeworks]

check w/ icc and ask them. we have real low pier and beam stuff here, so i've not seen this

 

[Buelligan]

check w/ icc and ask them. we have real low pier and beam stuff here, so i've not seen this

I will do that but I will also try to take and post a few examples tomorrow.

 

[codeworks]

also, if it's not installed per muinufacterors spec, it is NO GOOD. contrary to a popular misconceived belief, at least here in texas, a building inspector can trump an engineer, especially when the engineer is wrong. i've done fdn inspections (preplacement) steel/forms,etc where "the engineer was just here amd he said it was good" where steel was too close to earth, not properly tied, improper lap splices, etc. etc., made me want to turn the guy in to the state. i just pushed the builder, eventually argued with the builder till he got the engineer on the phone, then i gave him a piece of my mind. it got corected. I got my point across. they may not like me, but they do have more respect for this office than they used to. (some, not all)

 

[mtlogcabin]

Response from the manufacturer.

Mr. ......,

The purpose of encasing the screw side of the column in concreteis to insure that the screw cannot be adjusted/tampered with after a properinstallation. We understand that the consistency of concrete used in abasement application is 3500 psi.

Bob Kinney

Sales Manager

 

[codeworks]

thank you, mtlogcabin

 

[Buelligan]

Response from the manufacturer.Mr. ......,

The purpose of encasing the screw side of the column in concreteis to insure that the screw cannot be adjusted/tampered with after a properinstallation. We understand that the consistency of concrete used in abasement application is 3500 psi.

Bob Kinney

Sales Manager

Thank you for the response, but that was not the response I got from the manufacturer I spoke with, Marshall Stamping. His response was that the ICC codes required it with no mention of disabling the screw. Also as stated in the ATI report is the requirement that "The entire adjustment mechanism, including the entire collar nut, shall be encased in minimum 3500 psi concrete." There are absolutly no other provisions for installation listed. The section above that quote states "where differences occur between this report and the manufacturer's installation instructions, this report shall govern" So can the engineer override the report? I didn't think so.

So no opinions on whether or not the column should support the entire load as opposed to the threads? I would really appreciate your opinion guys!

Anyway so far I have found that unless the "entire threaded mechanism" is encased a fixed column MUST be used right?

No inspections today so no pics yet.

 

[ICE]

We don't use these around here but from looking at the product, it appears that the threads do bear the load.

The 3500 psi concrete requirement is there because they didn't know that it can be had at 5000 psi.

Many years ago, I worked on a four story building that had huge all-thread anchors with steel plates on the ends. I can't remember the exact dimensions but it was 8' long and 2" diameter or there abouts. Well anyway they came up short by quite a few inches so a forklift, chain and wrench were used to unscrew them from the foundation.

 

[TimNY]

Check the ICC-ES report, if there is one. The Tapco Monopost report specifically says encased in concrete.

Tim