Rectangular Foundation - Zone of Influence

[geojosh84]

I am trying to get a rough estimate on settlements beneath a 4' x 6' slab loaded with 35 kips (non-eccentric). The bearing material is predominantly sands (SC). Am I being over conservative with a 12' settlement seat? I am using schmertmann's method to give approximations. Thanks in advance.

J

 

[BigH]

Sorry for the late reply. Text - Kramer's Geotechnical Earthquake Engineering, Chapter 9 is one. Handy and Spanger, Geo book, section 27 is another. The text I used is in deep storage in Toronto and don't remember the name of it. But Kramer's is probably the best and most complete for the whole gamut of seismic and liquefaction. Richart Hall and Woods for machine foundations along with Barkan.

 

[geojosh84]

BigH, no sweat. I will def look into that, I am still a little wet behind the ears when it comes to calculating seismic induced settlements. The only way I really I know is from a pretty straight forward excel sheet based off the format laid out by seed and idriss. Sometimes I feel that I have seen too liberal of an approach on what conditions are prone to liquefy. I am under supervision that states a N greater than 3 and greater than 5% fines will not liquefy. My calcs state otherwise sometimes. I guess experience will work this out over time. Sorry for the tangent from the original post topic.

 

[fattdad]

I did a job at Fort Benning. Fairly clean sand atop a marine clay. Sand with moderate blow counts. Clay with very high blow counts. Clay also with low friction angle. Large-scale slope failure developed. Consultant lulled into the, "high blow counts, what could go wrong problem. . . ?" Oh, a lot went wrong!

f-d

ípapß gordo ainÆt no madre flaca!

 

[geojosh84]

fatdad, thanks for sharing. I definitely feel that this could be the case. Was that caused by liquefaction?

 

[fattdad]

no, in my case it was just the changes in effective stress resulting from earthwork.

f-d

ípapß gordo ainÆt no madre flaca!