Steel Jack Posts & loss of "permanent load" rating...

[CELinOttawa]

Jack Posts - Anyone else seeing more and more of these little steel screw-columns which are not rated for permanent loads? They seem to be pushing the old standard steel jack post out of the market. The one's I've seen are all painted grey, and the most common manufacturer seems to be "Tiger Brand".

Anyone allowing these? Are people noticing a problem? Thoughts?

 

[AELLC]

"Tiger Brand"

Sounds like the welds will be brittle and the threads will shear easily. Better to use Simpson J/JP.

 

[EngineeringEric]

I have seen problems with these on some commercial projects. (Yes commercial sadly)

The biggest issue i have seen are sloped installation, the thin caps walk away or crush under loading, and sub-par footings. Most of the problems were with contractors not the product, besides the flimsy caps! I have not allowed these jacks, but my more senior co-worker has. He specified better caps and bases as well as other specifics, but the product was the same/similar.

 

[dhengr]

CELinOttawa:
Any number of those jack posts have served the building industry for generations, and many of them have been in place that long too. Like everything else in our business these days, the ICC and their testing and certifying arm would like everything to go through them, for what it is worth to sustaining their profit centers and cottage industry. Then once you have their expensive and less than tidy reports, maybe you can use them, if they still meet the ever changing code. You and I can certainly design and fab. our own jack posts, but that’s not an off the shelf item without their blessing, and probably requires our stamp. My guess is that some of the junk the big box stores are buying is getting thinner and lighter to keep the price down, so it is suspect. Certainly, they should have some installation instructions and height/load rating standards. There has also been code discussion about immobilizing the jacking feature after installation, so they can’t be messed with. I always thought that was why you took the round bar out of the screw stock hole after you adjusted the height, but that has been deemed not to be foolproof enough. Now, I’ve heard talk that some AHJ’s want you to tack weld the threads or put them in upside down and bury them in conc. at the ftg. As we dumb-down the people we allow to pretend to be builders, and try to protect them from themselves, even more must be codified to the last letter.

 

[CELinOttawa]

Oh no, no dhengr; I'm not at all against rated jack posts! Don't get me wrong... It is that these new ones are NOT proper CAN/CGSB 7.2-94 rated jacks, they just look EXACTLY the same AND HAVE A RATING ON THEM. So far I have not seen one specify that it is not for permanent loads where it should: ON THE JACK. Not knowing the product I went and looked in the literature, where you find out that this is "Not for Permanent Loading". [Aside: No clue as to the US specification for these and have never seen them in Aussie as well as know them to be absent from the NZ market.]

I have nothing against what I'd call the "real deal" but these simply aren't it. They appeared a while ago and seem to now be pushing out the proper structural jacks. It may very well be a costing issue as you say dhengr, but to me this is a liability minefield. They are labelled and marketted as for "temporary loads", "secondary loads" and repair of "lively floors", and in use as main structural elements!

 

[JStephen]

Some time back, I ran into an issue with some lifting equipment. In particular, a lot of the lifting/hoisting equipment and hardware available will have disclaimers on it that say "Not for lifting people or lifting loads over people". However, as far as I could tell, this doesn't disqualify it from being used for that application, as far as OSHA is concerned. This seems to be a similar issue to what you're running into. Either they're saving money by making a substandard product, or trying to limit liability by labeling that disclaims the very purpose for which you'd buy the product. I wouldn't arbitrarily disqualify based on that, but would investigate it a lot more based on that.

 

[AELLC]

Are you specifying ICC-rated jacks, and still seeing these "mystery origin" jacks being installed?

 

[CELinOttawa]

You've got it AELLC... Canadian equivalent situation, mind. And I'm not shy about forcing them out, just don't like seeing the problem and have gotten to wondering if this is a trend.

@JStephen: Could very well be a cheeky liability dodge attempt.

 

[XR250]

I allow these on residential retrofits in crawlspaces, but I always recommend that additional steel bearing plates be added. Also, they are supposed to be installed with the threaded end downwards if installed under a dropped beam. This keeps them "more" stable.

 

[CELinOttawa]

I am not a fan at all under a dropped beam, unless the dropped beam is given braces at that point or the threaded rod (downwards as ExcelEngineering points out) is encased in Concrete.

Excel: Do you mean to say you allow this with the CHEAP NEW ONES, or the rated "been around forever" proper Jack Post?

 

[XR250]

I allow the cheap new ones, but generally the load on these is only in the 3 kip range and they are pretty short. Depending on the aspect ratio of the dropped beam, I will add bracing as well. I typically try to use (4)2x8 for dropped beams in crawlspace retrofits as they are pretty stable.