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[yogendrarathi]

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Dear all,

I am dealing with the design of two major bridges for HM loading. The GL is at 1.87m and MSL is at -10m. The borelog data I have, pertains the safe bearing capacity of 90t/m2 at -30m and 100 t/m2 at -41m. The said values are calculated using C and f(phi) parameters. As per my calculations I have to rest the well FDN nearly by -35m, but the f value given at that level is very less which is directly praportional to Nc, Nq and Ng; hence the end bearing capacity is coming very less, where as �N� value changes from 48 to 45 with a minute difference of 3. The soil is sandy clay and clayey silt with massive changes in layers. The soil also shows plastic behavior at higher depth.

I fill that resting of well just by assuming property of certain level is not right and we should always take the reference of �N� value for calculating safe bearing pressure.

Now my question is that, if you agreed with me then please tell me that how to calculate the safe bearing pressure and settlement using �N� values in layered soil.

In this case I referred one table 52.7 which have given the reference of Meyerhof experiment,says that,

For no plastic silt Ultimate end bearing is 10(L/d)N <= 100N

Where, L � Embedded length

d � Dia. Of section

But these values are in Kpa and if I convert it to t/m2, I am getting very less SBC.

So I request you all to guide me in this regard if you know anything.

In wait of your fruitful reply,

Thanking you,

Regard
Yogendra C. Rathi
M.Tech(Structural Engg.)
Consulting Engineer
SOWiL Limited,New Mumbai.
Mob:9819035121 (Mumbai)

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[lele_raj]

Hi Yogendra,

Foundation Design and Analysis (Bowles) has excellent explanation about your query. It may have some programs on the disk.

Thanks and regards,

Rajendra (Raj) Lele

----- Original Message ----
Message From "yogendrarathi[AT]red..."
To: lele_raj[AT]yah...
Sent: Thursday, 14 December, 2006 6:13:48 AM
Subject: Calculation of SBC?

Dear all,

I am dealing with the design of two major bridges for HM loading. The GL is at 1.87m and MSL is at -10m. The borelog data I have, pertains the safe bearing capacity of 90t/m2 at -30m and 100 t/m2 at -41m. The said values are calculated using C and f(phi) parameters. As per my calculations I have to rest the well FDN nearly by -35m, but the f value given at that level is very less which is directly praportional to Nc, Nq and Ng; hence the end bearing capacity is coming very less, where as �N� value changes from 48 to 45 with a minute difference of 3. The soil is sandy clay and clayey silt with massive changes in layers. The soil also shows plastic behavior at higher depth.

I fill that resting of well just by assuming property of certain level is not right and we should always take the reference of �N� value for calculating safe bearing pressure.

Now my question is that, if you agreed with me then please tell me that how to calculate the safe bearing pressure and settlement using �N� values in layered soil.

In this case I referred one table 52.7 which have given the reference of Meyerhof experiment,says that,

For no plastic silt Ultimate end bearing is 10(L/d)N <= 100N

Where, L � Embedded length

d � Dia. Of section

But these values are in Kpa and if I convert it to t/m2, I am getting very less SBC.

So I request you all to guide me in this regard if you know anything.

In wait of your fruitful reply,

Thanking you,

Regard
Yogendra C. Rathi
M.Tech(Structural Engg.)
Consulting Engineer
SOWiL Limited,New Mumbai.
Mob:9819035121 (Mumbai)

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