How to obtain differential settlement for in foundations
How to obtain differential settlement for in foundations
(OP)
I have run some settlement analysis of soil and understood that I have a total of 37 mm of settlement under a 1.7 m x 4 m spread footing. There are 3 similar footings 10 m c/c. Soil profile is similar for all. Can I calculate the potential differential settlement?
Would the differential settlement be with regards to one footing itself or with regards to one footing against the other footing.
Would the differential settlement be with regards to one footing itself or with regards to one footing against the other footing.






RE: How to obtain differential settlement for in foundations
In the downloadable document for foundations of the spanish CTE you can see what restrictions are expected here to be respected respect differential settlements between different points at the foundation.
RE: How to obtain differential settlement for in foundations
Differential settlement is the DIFFERENCE in settlement between any two foundation elements, typically between any two column footings.
So to answer your first question, yes...you can calculate differential settlement between the footings; however, if you calculated 37mm of settlement and you do the same calculations with the same footing size and loads, resting on the same soil profile, you should get the same estimate of settlement...37mm. That would indicate that all would settle the same amount or in other words, you would have UNIFORM settlement, not differential settlement. If the soil profile or other parameters are different, then you might get a different settlement value, thus differential settlement between the two elements that you compare.
Not sure what you are evaluating, but 37mm is quite a bit of settlement. If you have that much differential settlement in 10m, it will induce a lot of stress in the structure and will severely crack masonry.
RE: How to obtain differential settlement for in foundations
(I am a little confused as often in geotechnical practice they say the settlement is .. 25 mm and differential settlement assumed 3/4 of it i.e. 19 mm and cannot recall where the 3/4 comes from.)
Thanks.
RE: How to obtain differential settlement for in foundations
For a gantry crane on three footings, I'd be concerned about uplift as well. 37mm of settlement for a gantry crane, in my opinion, is excessive...uniform or differential.
RE: How to obtain differential settlement for in foundations
RE: How to obtain differential settlement for in foundations
I'm not an expert though, and if you aren't familiar with the calculations to determine expected differential settlement, I'd find someone who is that can help you.
I would think the typical 3/4" inch of differential settlement across the foundation is a CYA statement in a lot of geotechnical reports when they expect the differential settlement to be reasonably low.
RE: How to obtain differential settlement for in foundations
How does that work? I'm curious
RE: How to obtain differential settlement for in foundations
RE: How to obtain differential settlement for in foundations
Just talking from the back seat here.
RE: How to obtain differential settlement for in foundations