Failure about to happen? 14

[JAE]

I think so....

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[JAE]

So drawing a straight line from bottom mid-point on column to top mid-point on column there is definitely some bow in it.

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[Brad805]

Wow. Regardless of the numbers, would not seal.

I suspect the roof level needed to be changed because they needed new racking or it was a new tenant. They set jacking equipment under the beam ends, cut the beam, jacked it up, and did not want to put in the effort to cut out the beam segment that remained. Saved $2k - 5k in welding/testing a full penetration weld.

 

[dik]

It just dawned on me, "Why would anyone do that?"... let alone an engineer review and accept that... really scarey, and if it goes, it will go catastrophically... no warning... 'bang' and it's down. Someone should notify the building department rather than just chat about it.

Dik

 

[thebard3]

It would be funny if that was an unneeded pillar and instead of tearing the pillar down they connected it to just keep it upright.

That looks awfully structural to me. It's at a transition from a beam to a truss so there is definitely a bending moment on it. But, I'm not a structural guy.

Brad

It's all okay as long as it's okay.

 

[IRstuff]

The photo is a bit misleading; you can see that the topmost flange is twisted relative to the truss directly above it. The apparent bow is partly due to the fact that the hole in the top flange is not aligned with the stuff below it. If you were to extend the line to where the hole should be, that middle section wouldn't look as bowed.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[zeusfaber]

Why the holes? Presumably to impart strength - in the same way the perforations in bog roll do.

Taking tongue out of cheek now: How did that stiffener get there? Is there a type of rolled beam that comes with stiffeners like that scattered here and there along its length (how would you go about making such a product?) or is the presence of the stiffener evidence that somebody put real thought and effort into making a special fabrication?

A.

 

[hokie66]

I think it is apparent that the building was extended, both horizontally and vertically. The short piece of WF which now forms part of the column was once a roof beam, part of a cantilever and drop in system. Probably very little if any involvement in the extension by a qualified engineer.

 

[MintJulep]

I'm guess that the original section spanned several columns in the original life of the building. Perhaps for a crane?

When converted to retail that was probably no longer architecturally acceptable, so just cut out the bits between columns.

But still, welding in that stiffener was probably more expensive than fabricating and installing a proper column shape.

 

[JAE]

This was and is a retail building.
There is also another detail just beyond this one in the first photo I posted.

I believe that hokie66 is correct - the building was altered (vertically and horizontally) and they simply built the new structure up and then later came back and cut away the beam below, leaving the stub there to serve as a part of the vertical column.

This will be pushed to the local building dept. by me. I feel an obligation to at least raise the issue with them.

Just thought it was an appropriate "failure" for this forum.



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[BridgeSmith]

My eyes may be deceiving me, but that stiffened plate looks to be about the same height as the WF beam connected to the top of the column. Any chance they originally planned for Beam to sit atop the column. and that's how it ended up too short?

 

[Agent666]

Moral of the story - got an issue, just add stiffener(s) till it looks like it might work.

Be interesting to see how the original designer justified that to themselves...

 

[LittleInch]

I think hokie66 and hot rod have it nailed.


If you take that stub extension piece and rotate it 90 degrees it more or less matches the end of the deep beam which presumably sat on the column post. That kind of explains why is has a set of holes drilled in it - it was originally on the end of the beam and intended to connect to another beam?

Now the Truss comes along and they want to support it on the top flange so need the column extended the height of the column - easy, let's just prop the beam, chop off the end section of the beam, weld on a teeny weeny angle bracket and use the cut off end as an extension piece....Oh and we'd better weld on a stiffener to stop the beam piece buckling - only one mind!

So the truss section is the horizontal extension.

Is it just me or does it look like the bottom of that stub extension piece is just resting on the top of the column? i.e. not bolted?

Still looks horrible.

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Also: If you get a response it's polite to respond to it.

 

[Agent666]

Probably (hopefully) welded.

 

[msquared48]

This is a Walmart building extender... patent pending...

Mike McCann, PE, SE (WA)

 

[hokie66]

I imagine the stiffener was always there. It is typical practice to provide stiffeners where a beam passes over a column.

 

[racookpe1978]

True: Ominously, I don't see any bolts between the end of the truss (all the way up at the roof) and the flat plate on the final vertical part of the column. Only two empty drilled holes.

I suspect the earlier diagnosis is correct: The WF was intended to rest on the top of the column, but the field changed it to a bolted joint to the web of the WF. The rest was a cut-and-fit job to get the height right.

 

[hokie66]

racookpe,
I think it would be standard practice to weld rather than bolt that truss girder to the supporting column.

The WF at the top was originally bolted to the lower WF, then the connection was changed when the roof was raised. Is that what you meant?

 

[racookpe1978]

Yes.

 

[JAE]

The local authority has been copied on these photos with an address. We'll see if anything comes to pass on it.

Here's the (redacted) text of my email to them:

[blue]As we discussed this afternoon, the attached photos are of a column configuration that one of my engineers saw in a local building.
The address is #################.

This is a “big box” retail building and I believe there are at least two columns with this condition.

Since I am a licensed SE in ######, seeing a detail like this where I believe that there may be a public safety issue compels me to bring this to the attention of either the building owner or you. I don’t know who is the owner so I am forwarding this concern to you to see if you believes that some notice or action is required.

I have not performed any calculations or analysis of this other than visual examination of the conditions.

Two of the photos (Bad Column Details 3 and close-up in 4) include a redline on the photo which shows a perceived slight bowing of the column arrangement such that bending in this configuration could be magnified by heavy roof snow loads and possibly lead to second order effects on the column.

It appears that this may have been a building with a lower existing roof frame that had a newer, higher roof system built using an upper column extension over the original roof beam. The new upper roof was framed in and the lower roof beams were cut off completely except for the portion of beam in line with the column.

From one photo there is a vertical plate stiffener on the web of the beam piece, but this is on one side only.

From my perspective, I would think that the appropriate action would be to have the building owner contact the original engineer, if available, to review this as-built condition and respond as to its capacity with respect to the Omaha Building Code provisions for roof dead load, snow, live, etc.

They could also hire another engineer as well to get an unbiased look at it. We, of course, would recuse ourselves from that effort.

It may result in a finding that the column is adequate but visually it is such an unusual configuration that we feel it best to have a closer look at it.

Please contact me if you have any questions.[/blue]


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[TehMightyEngineer]

I'd caution about mentioning the bending (if it's not too late to edit). Cell phone cameras tend to have a minor fish-eye quality due to the tiny lens. This may be the source of the curvature (or may not).

Edit: Also, typo:

so I am forwarding this concern to you to see if you believes that some notice or action is required.

Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

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