Stakes for Formwork Bracing

[mikeCTE]

Are there any design guidelines and/or examples of how to calculate the capacity of a stake (rebar or 2x4) driven into the ground a few feet to support a knee brace for formwork windload? I'm sure if we ran an AllPile analysis, the capacity will be quite low, but in reality, it's pretty reasonable.

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[SlideRuleEra]

...how to calculate the capacity of a stake (rebar or 2x4) driven into the ground a few feet...

No guidelines that I know of. Capacity will depend on soil properties. Can't say that I have come across formwork bracing stakes driven "a few feet" in the ground.

IMHO, if soil was "bad" enough to do that, stakes would not achieve fixity and loading would cause stakes to fail quickly (rotate) when load was applied.

On the other hand, if the soil was "good" and the stakes were embedded "a few feet", bending / shear capacity of rebar or lumber would be the limit.

http://www.SlideRuleEra.net

 

[oldestguy]

I'd contact a foundation contractor. By experience he likely has a few "rules". Once the forms give way with fresh concrete one learns a lot.