Ladies and Gents,
Just wanted to share the below images of a pier assembly to hear your thoughts on what may have led to the buckling of these connector plates…
Looks like the small concrete column has crushed under compression. Under design
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That is a poor design and construction. I would refer that out to a S.E.
Under designed for the loading. Compression of the small wood column was enough to buckle that stirrup. Judging from that beam, there is a lot of weight above.
Engineering evaluation definitely required.
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Since there’s an air gap between that horizontal steel square under the wood 5x5 and the crushed concrete (from whatever cause), it follows that the entire weight was resting on the bottom of the longer metal straps that appear to be connected as one U-shaped piece running through the lower part of the site-fabricated concrete.
Because the steel buckled so badly it could not have been designed by an engineer factoring in a simple redundancy factor to support the entire load on those straps, leaving the whole elaborate thing dependent on the indeterminate crushing strength of that site-fabricated block in an application the builder’s people had probably never seen before. In any case, it looks like a relatively easy fix as far as structural issues go. I hope the person who posted this will provide an update when he finds out what the story is.
I failed to see that second picture awhile ago and I would have to agree with Daniel.
Due to the rough texture of the surface of that concrete pier, you ended up with pin point loading on areas of the top surface of the concrete pier and therefore the loading was transferred to the side of that stirrup and the buckling caused the pier to break apart.
Leveling grout should have been used for that bearing plate.
That is an odd Simpson Post base anchor.
I don’t believe the side straps that are buckling are part of the post/beam anchor. They look separate to me? Without those straps, then its a standard Simpson post/beam anchor
Thanks for all the responses received up to this point. I plan to circle back around with more information to share as the developments unfold. In the mean time I’m all ears about other or further insights.
I agree Joe, used some of those before, (smaller ones) and that almost looks like it was welded on after the column was cast, and the framing started.
Not enough concrete surrounded the bracket for one thing
I agree, that pier should have been a minimum of 16" sq. and maybe 2’ sq. depending on the load so those straps would have been totally encapsulated in the concrete.
Thanks to Simon for blowing that up, showing that beam to post anchor was improvised.
Wonder if the differing materials expansion rates (steel, concrete, wood) thermal (all) & humidity (wood) caused the concrete damage. Small bits of concrete still on the floor, so recent movement. If the post was installed damp, as new lumber often is, then it would shrink as it dried. And if the cement was still green…
Sigh - I wish the crawlspaces here were 1/10 that nice.
Recommend employing a PE and say nothing else. Our job is to report our findings. It is very easy to get into the trap of diagnosing the problem. Every word you speak to the client can be used against you. It is a lot less stressful when you let the P.E.s handle the diagnoses.
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There is more to the story somewhere. Starts off as a CMU pier, then concrete extension followed by a wood block extension. Looks like someone changed their mind on the crawlspace height a couple of times. Also something odd about that bracket, looks like it was developed for a different application. I would say a conversation with the builder would help clear this up.
I think Simon’s picture blow-up explains the modification to the Simpson beam to post connector.
I have used some of those heavy duty connectors before and that is why in earlier post I said there was something odd about it until this blow-up explained what was odd about it.
Looks to me like the concrete failed. Was a core sample taken to verify the PSI strength of the concrete? What was the desgn mix of the concrete?
Failed because it was never big enough to encapsulate the anchor, regardless of the PSI. Standard PSI is 2500 # for residential and that is weak in my book.
2500 psi is a absolutne minimum for residential but columns need 3000 to 5000 psi and should be sized right, attached and reinforced if needed.
Agree with Marcel this column is to small at least.
As was posted above we should not offer any brilliant solutions how to solve this type defects.
The only time the IRC requires 3000# psi is when exposed to weather.
So 3000PSI would be hoping for the best with most residential contractors.
I was commercial/industrial all my life and 3000psi was the minimum and used pretty much for everything.
Elevated beams might have been 4000 and I also use that on some floors and sidewalks.
It would surprise me in the OP’s picture if that was a 3000psi the way it shattered.