Yes you can use the same model but you should perform a separate analysis, one for the undrained condition (short term) and the other for drained condition (long term).
BigH - I also had experienced that situation once, light weathered rock was found at 2 - 3 meter elevation at some location...I substitute my precast piles with mat foundation, it is too difficult to penetrate the weathered rock layer.
My point is, whether it is a franki piles or mat...
Agree with oldestguy. What kind of geotechnical team would advice to install driven piles when N-SPT > 60 ? Based on this decision alone, for me it is doubtful that they are really a geotechnical engineer.
@JSD1986 :
The example that you asked about is at Flexible Footing Section. Notice from the first paragraph,
"The calculation is now modified so that the footing is modelled as a flexible plate" (no longer circular).
For flexible plate, PLAXIS calculate A (area) from the plate as diameter x...
Kpaudel :
Structural engineer usually used load combinations based on code such as IBC :
a.DL (dead load) + LL (live load)
b.1.2 DL + 1.6 LL
c.0.9 D + E (earthquake load), etc.
Noted that some of the combination is factored with SF (1.2 for dead load, 1.6 for live load for examples).
They...
Kpaudel :
I will give you the rough idea if a single pile were installed :
For end bearing capacity, you got :
Qp = 9 Su Ap = 9*150*Ap = 1350 Ap (in kN) with Ap = cross sectional area of the pile = 0.25*3.14*diameter^2
For friction capacity, assuming that Su would be 150 kPa from top to bottom...
civeng80 :
I think factor of safety has nothing to do with the settlement.
Let say that because of 120 kN load, your foundation settled for 20 mm.
For 120 kN load action, the foundation with 469 kN capacity will give a reaction force of 120 kN, not 469 kN.
So whether you divide the capacity of...
keenkeem :
For a simple static load method, usually the seismic force will be calculated as lateral load working at the center of mass gravity, let just call it H(eq).
H(eq) = W x a/g ;
with W = mass or self weight of the structure
a = maximum earthquake acceleration at ground surface (in g...
oldestguy:
It's hard to get a good result if the team had not shared the same passion and determination to get the job done right..and to think that they were your own employees, I guess I won't get my expectations too high for my team then, since they're just an outsiders hired for the job...
Well now you make me feel doubtful of all field data that piling up at my desk. To think of it, mostly I don't know
how they were taken, which method they use, were they having some troubles when they do the test, etc.
Maybe the best thing that I should do is always watching them closely when...
oldestguy:
Found several fissures on some samples, 2 - 3 samples are not fully intact. I suspect the damage occur during sampling (unfortunately I wasn't there, the soil investigation was conduct by someone else, I just received their result).
Based on their report, yes they were using...
moe333 :
Thanks for your suggestion. I think I'm agree with you, it behaves more like clay than sand.
Sorry that my question deeply involved judgment engineering, not technical.
oldestguy:
That's a great idea, thank you !
I think I will try pocket penetrometer on the sample. But since the...
oldestguy:
Thank you oldestguy, I've read it. But it still doesn't answered my question.
I could use the Meyerhoff equation from page 200 US Navy manual for granular soil (sand). and it cannot be used for cohesive soil. So for cohesive soil then I could use equation like qp = 9 Su and fs =...
Hi all,
I need some advices on pile design method. I only have N-SPT data, so I’m going to use N-SPT method. As far as I know, the equation for pile bearing capacity is governed by 2 conditions : drained (granular soil) and undrained (cohesive soils). It’s easy if the soil are simply cohesive...
RFreund,
It's an equation from Plate Bearing Test by Terzaghi. Modulus subgrade reaction ks is conceptual only, not soil parameter.
The story began when Terzaghi tried to relate the vertical deflection (d) of a shallow foundation to the load that applied on that foundation (q). Then he defined...
