Bearing Capacity Check

[Mohame Abo-Ewesha]

Hi,
I`d like to know the if there are any guidelines about when to use low estimate, High Estimate or best estimate values of undrained soil shear strength for the bearing capacity calculations under the shallow foundation used as a pipeline support.
Note: the foundation will be on the seabed level.

 

[EireChch]

Why would you not always use "best estimate"?

 

[Lomarandil]

Yes, use the best estimate

The one exception would be in cases where you need to check the sensitivity of the structure -- then check the envelope of the low and high estimates.

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The name is a long story -- just call me Lo.

 

[fattdad]

My instructions sort of went like this. . . assuming all you have to go on is SPT N-values.

Let's say you have six borings that go to 30 ft. Let's say that the depth where the stress increase is greater than 10 percent existing overburden pressure is about 20 ft. I was taught to take the average N-value in the seat of settlement for each boring. I was then taught to characterize the stratum (strata), by the lowest average N-value obtained from the seat of settlement of each boring.

Now in highly layered soils and foundation loads that go to greater depths, that simplification may be in error. So, I'd have to reckon through that.

f-d

ípapß gordo ainÆt no madre flaca!