Steel columns with no anchoring bolts 1

[Alan CA]

Hi everyone,

I reviewed a residential house last week in Ontario and I noted that not a single tube steel column in the basement is anchored to the footing (where footing or concrete piers were visible, or as construction photos show). The contractor is arguing that he consulted with an engineer who calculated wjnd uplift (in the basement) and he figured theybwere okay. Design drawings call for anchoring bolts.
I'm concerned about this regardless of what the engineer's calculations indicate, especially that the columns are already out of plumb.

What do you think?

 

[DoubleStud]

Seems easier to make them install epoxy anchors.

 

[phamENG]

I think since nominal Anchorage is absolutely necessary. There's more than uplift to consider.

 

[Alan CA]

Exactly! I never find peace of mind with some calculations indicating it's ok to let such steel frames rest freely with no anchors, windlift ol or not!

Regarding epoxy anchors, could be a solution once the dispute is settled!

 

[SWComposites]

Alan - are you the EOR? Or some other role?

 

[BridgeSmith]

Ask the contractor if the engineer he consulted is willing to stamp revised structural plans without the anchors. If not, then he needs to follow the plans and put them in, otherwise, it won't pass inspection, will it? At least that's how I thought it's supposed to work.

 

[canwesteng]

Notional loads to account for out of plumbness are required by code for steel construction and mean there is always some shear to contend with. If the EOR thinks there are only small loads, get them to sign off on putting some tapcons into the slab, it takes like 30 minutes with a drill.

 

[Enable]

I'm in your jurisdiction and this is fairly common for residential. The slab will brace the post or is assumed to and uplift would not likely factor into this for a prescriptive code design (CMU / concrete foundation walls for miles and all that). Actually, usually there isn't a footing it's just some sort of thickening that the posts are cast into or set on top of. The tops usually are anchored with bent straps rather than bolts/welds as well.

I guess what I'd take from this is that if you're the EOR or acting for them and your plans call for anchorage then tell them to piss off; and add the anchorage. If you're in some other role then I think politics would guide you more than anything.

 

[Ron247]

If the plans call for bolts, make them put them in. To me, there is no debate, that is the purpose of having a set of plans. There is more to worry about than just wind uplift. They should also consider some uplift from the floor beam possibly being continuous span. Where I work, they are almost always continuous. I have also seen one span loaded a lot more than adjacent spans. There is nothing like full file cabinets, full bookcases or old Xerox paper boxes stacked to the ceiling with old paperwork in them.

As far as the engineer who he consulted, he would have to sign off on the lack of bolts in its entirety, not just saying he checked wind uplift.

And as a sidenote, I see them all the time without anchor bolts, but they are not my designs and I am not inspected the work either.

 

[Gus14]

I live in a different continent but I can't help but wonder even if uplift is not an issue. If bolts are not required, then how does the lateral force resisting steel frame transfer the shear force into the footing ? Is it relying on a concrete shear wall ?

 

[Ron247]

In most cases, it is not a steel frame in the classical sense, they are individual steel columns under a beam with very little ability to resist moment at the column to beam connection. Any lateral resistance is predominantly friction.

 

[XR250]

It is common in my area not to anchor the columns. Low seismic activity, 115 mph wind.
Never seen an issue in my 32 years of field work
Maybe if the kid has a go-kart in the basement I would be concerned.

 

[Gus14]

they are individual steel columns under a beam with very little ability to resist moment at the column to beam connection. Any lateral resistance is predominantly friction.

Interesting, it's weird that the local building code doesn't require a minimum. I never thought contractors would try to save money on a couple of anchor bolts.

 

[canwesteng]

In canada there is usually lateral resistance at the base because the posts are cast into the slab. I'd probably ask them to screw the post base plate into the slab if this isn't done, but far from my bread and butter type of work.

 

[hokie66]

How do they erect the columns without anchor bolts? I had the impression that safety codes provided that anchorage is required to stabilize the columns during construction.

 

[Enable]

Below is a picture of common attachment from post to beam in a residential scenario where the OP is located. I think this might be so foreign to some of you that it causes a short circuit. But more often then not in my experience these columns are hung from the beam with bent tabs and then cast into the SOG / thickening. No anchor bolts required!

We typically have 7-8' basements with concrete or CMU foundation walls that are more than enough to handle the environmental loads by their lonesome, so the column's entire enterprise is to reduce the span of the steel beam. We like to put wimpy beams in basements for some really irritating, silly reason.

Depending on order of operations dead load is applied before there is any support at the column, but they just cover that up with a slightly deeper bulkhead.

 

[kissymoose]

columns are hung from the beam with bent tabs and then cast into the SOG / thickening

That's nice. You've heard of prestressing, now try predeflection.

 

[hokie66]

That didn't make me short circuit, but I did cringe.

 

[XR250]

Here's one I saw yesterday....

 

[bones206]

This is from my own basement... true craftsmen lol