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Push Pier Underpinning Fail

Push Pier Underpinning Fail

Push Pier Underpinning Fail

(OP)
A residential project I was working on had its gable end foundation wall underpinned. The foundation had settled 3". Fortunately, I was not involved in this aspect of the project.
The foundation contractor installed helical piers without notching the footing or bolting the brackets to the footing. The foundation wall was about 7 ft. tall and consisted of 4" brick with 4" CMU backup. The majority of the framing was parallel to the wall except the center girder of the crawlspace. The house is one story with brick veneer.
When the contractor tried lifting the wall, the footing rotated and failed the foundation wall. Ironically, there was an engineer on site overseeing this.
The foundation wall and veneer is now being replaced.
I only have a picture of the piers and the footing (not a good one). The foundation wall had already been removed.
I guess the moral of the story is, you cannot ignore the laws of physics. Eccentricity is a real phenomenon.
When spec'ing underpinning, make sure the footing gets notched and alternate the piers from interior to exterior, if possible, to balance out the potential rotation.

RE: Push Pier Underpinning Fail

The gable end ... the lightest wall settled the most ... Hmmm!
From your description & the photo the contractor made at least 2 extraordinary errors, to say nothing of the engineer who was on-site. (Who knows? maybe having this particular engineer on-site was a mistake all in itself).

I also anticipate & probably agree with, the comments of Oldest Guy, regarding the likely near useless drain.

RE: Push Pier Underpinning Fail

How'd I get into this one? Anyhow, one heck of a lot of open graded stone.

RE: Push Pier Underpinning Fail

Resolving the eccentricities in a helical pier with virtually not bending capacity has always been a tricky thing when clipping off the footing to get up against the wall. With the footing sticking out like that, likely doomed from the start.

RE: Push Pier Underpinning Fail

(OP)
Most definitely. IMHO, the whole concept is sketchy and I don't really believe a lot of the manufacturer's testing numbers. They seem to work somewhat OK on the residential jobs I observe, however.

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