P-Y Curves
P-Y Curves
(OP)
Does anyone know where i can obtain a spreadsheet that computes p-y for various layers such as clay, sand ?
I realize that programs such as COM624 and LPile compute these but sometimes you have to input based on modfied soi layers.
Thanks,
TRE
I realize that programs such as COM624 and LPile compute these but sometimes you have to input based on modfied soi layers.
Thanks,
TRE





RE: P-Y Curves
I have used a P-Y excel spreadsheet from the following source:
https
You can download the zipped file and extract to open.
VTengineer
Geotechnical
Ryan R. Smith
Geotechnical Engineer
RE: P-Y Curves
RE: P-Y Curves
RE: P-Y Curves
Excellent advice, which should be extended to all analysis/design software from anywhere. As the statistician George Box said, "essentially, all models are wrong, but some are useful".
But assuming FixedEarth is referring to my LatPilePY spreadsheet, is it true that the shear values are wrong with depth? That depends on what sort of "wrong" we are talking about. As far as I know, for given loading, pile section properties, and spring stiffness values, the output shears, bending moments and deflections are in static equilibrium, and in accordance with the standard theory of bending, although users should of course check that.
Where the spreadsheet could be said to be "wrong" is that for a specified set of soil properties it will generate a different set of py curves to that generated by COM624. The main reason is that COM624 uses an initial stiffness value for sands and stiff clays that is proportional to depth and independent of pile diameter:
P = kxy
P = soil force/m
k = initial stiffness constant
x = depth below ground level
y = pile deflection.
In the current implementation of the spreadsheet I have multiplied the k value by the pile diameter, rather than the depth below ground level, so the stiffness is proportional to pile diameter, and independent of depth.
Both approaches are of course gross approximations, but either can produce useful results, if the results are reveiwed by an experienced engineer and checked against alternative analyses and testing.
The COM624 documentation gives very little justification for the approach used, and where the assumptions used have been examined by others they recommend caution in use of the results. For instance:
Nontheless, the PY curves generated by the spreadsheet were intended to follow the method used in COM624, which at present they don't do. A revised version of the spreadsheet will be posted in the next day or two that will provide the two options outlined above for calculation of the initial stiffness, with the COM624 method being the default.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: P-Y Curves
RE: P-Y Curves
We are in total agreement on that!
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: P-Y Curves
I totally agree, noone should ever use spreadsheets without a thorough review. We as professionals should take every precaution when dealing with information provided by others or the web. Good comments.
Ryan R. Smith
Geotechnical Engineer
RE: P-Y Curves
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Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/