Mod-1 Lec-1 Shallow Foundation

Mod-1 Lec-1 Shallow Foundation

Comments (24)

  1. Am learning a lot from here. God Lecturer

  2. very bad language…
    there is no try for explanation just telling what are given in the book
    very very bad than the other faculty of NPTEL

  3. thanks for ur wonderful teaching…

  4. Thank you very much!

  5. not trying to explain anything.. giving only superficial knowledge…. very bad teaching.

  6. prononciatn is soo poor…didnt xplain gud

  7. english ki ko hanth pair tod dya h sir ji aap ne…better hota k aap hindi me samjha dete…samajhna imp hai…chahe koi v language ho

  8. boring. No illustrations what so ever..

  9. Does there have English subtitles ?I am not an English speaker and I can not hear clearly.

  10. I appreciate your channels contribution to engineering, it has been very valuable. I only have one suggestion that I would highly appreciate if you could implement it: better quality videos (like 720p) & noise reduction. Otherwise what you are doing is perfect. Thank you.

  11. Good work sir .this lecture is very useful for us

  12. how can I ask Dr.N.K.Samadhiya a question?

  13. Only reading from slides, poor and less explanation.

  14. Only reading from slides, poor and less explanation.

  15. explain clear manner
    explain active force formula clear way
    stress is equal to force by area
    here active force equal to stress(or)pressure into area
    how it will come

  16. great to hear from you

  17. Sir agar 10 ft तक जमीन काली माट्टी की हैं तो उस जगह बाद में नरम पत्थर हैं तो कोनसा फाउंडेशन इस्तेमाल मे लाना चाहिए

  18. Thanks nptel Please add videos of work during lecture & pics.

  19. Hindi me batao chachu

  20. During my BE (Civil Engineering), ME (Soil Mechanics and Foundation Engineering) from University of Roorkee, Roorkee, India, and PhD (Civil Engineering with Geotechnical Emphasis) from the University of Missouri-Rolla, Rolla, USA, no teacher told me a practical fact, that “basically the behavior of a shallow foundation in controlled by the settlement, not bearing capacity.”  This fact has been stated by Ralf B.Peck in his book and lectures.

    When I joined Woodward-Clyde Consultants in Philadelphia in March 1986 upon completing my PhD, my boss, Dr. Arthur Dvinoff gave me to design a shallow foundation.  I completed the bearing capacity estimation
    in two or three pages, followed by settlement estimation.  I took these to him and he skipped the bearing capacity pages and just checked the settlement analysis.  I asked him the reason and he said that we don’t care about bearing capacity.  If the building is safe in settlement, it will be safe in bearing capacity.

    Anyway, if one plugs in the values in the bearing capacity equation, one may get a bearing capacity in several thousand of Pounds per Square Foot (psf).  Can one load that footing to that extent?  No, one can’t.  The structure would undergo a very large settlement.

    All those Plate Load Tests with a 6 inch by 6 inch plate are wastage of time.  No body does those in the USA.

    Professor Peck wrote the “Forward” for the book on Soil Dynamics by Dr. Shamsher Prakash.  On the second page of his forward, in the third paragraph He says:

    “Considerable progress has been made in determining the ultimate bearing capacity of footing and rafts. 
    The impetus for research in this area came largely from the need to
    design protective structures against the force of high energy atmospheric
    blasts. For non-military problems the ultimate bearing capacity is usually of little or no interest in comparison to the movements, particular when the subsoiloil is non cohesive………………”

    In my professional carrier I considered bearing capacity only once, while serving as Senior Geotechnical Engineer in the US Army.  It was required to dredge a canal for the transportation of ships.  There were some islands having the dimensions of quarter a mile and more.  The question was that how much load we can place on them.  My answer was – as much as the bearing capacity permits. Settlement was not a concern.  More settlement will give room for more dredge to be placed.

    All that said, I believe that at least once in a life time the student should be taught bearing capacity, but should be told the practical aspects  involved.

    You mention that for shallow foundation the ratio Df/B < 1.0.  Here our criteria is approximately 5 times (Reference: Page 7.2-177, Chapter 5, Deep Foundation, Naval Facility Engineering Command (NAVFAC) DM 7.02). Of course, here the footing bottom should be below frost depth.  In my area (Chicago) the official frost penetration depth is 40 inches, but the state of practice is 48 inches.  Therefore, we use 48 inches.  By the way, NAVFAC DM 7.1 (Soil Mechanics), DM 7.02 (Foundation Engineering) and NAVFAC 7.03 (Soil Dynamics) are my bibles and every geotechnical engineer uses them   You can also download them free.
    You mention that for deep foundation the area of column footing should be more than the loaded area. This is not clear to me. 

    You mention that the maximum permissible settlement is 75 mm (3 inches) to 100 mm. (4 inches).  This is a way too large for us.  In the USA, it is 1 inch for a spread or wall footing and 2 inches for a mat foundation. 

    We use mat foundation if the total area of the column and wall footings in more than half of the building area.

Comment here