Pile as spring below foundation

[lasalleguy]

may be too late.
try using dyna5 to compute the stiffness and damping values.

[Nedian]

Dear ASLAM!

Will you please re-upload your file so that we can learn from your experience regarding modelling of pile as a spring below foundation?

And I think, in this way you can fulfill the purpose of this forum to share experiences among each others.

I will highly appreciate your effort if you re-upload your file.

Thanks in advance.

Regards,
Nedian

[Red Alert]

Dear engineer ;
you can model the pile by using first autocad , then safe
1-on your drawing in autocad you can put the pile as a point and save it as DXF
2-import your file to safe , and then assign the loads

[rendel_©]

info:
I think image posted by aslam from post number 11 is this image as you can see in my screenshot below and this page can be seen in etabs manual from atkins that also aslam posted in software manuals
Yo can visit the below link so that you can see so many mirror link for this manual and there is also a direct link.

screenshots:


Download Links:

Code:

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[jaks]

Hi guys,

I am attaching a safe file which I had modelled for a raft over pile. The file is imported from ETABS.

Code:

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Well I have modelled the pile for vertical spring.

I have certain queries, may be the experienced engineers could shed some light on it,

1. I have seen in this thread the stress on using the horizontal springs, if somebody could eloborate as to how to calculate the same.

2. I wanted to check the punching shear at the piles as well as the columns, if somebody could eloborate on the same.

The pile diameter is 1.5m, the springs are calculated as pile dia/allowable displacement.

Regards,

Jaks.

[Sumatra]

Actually, you were asking about soil-pile interaction and how to apply it as a macro element in order to run global analysis of structure using software.

What you need to do is modeling a pile carrying axial compression and lateral loads. It is modeled as a system of rigid elements (like column but no flexural) connected by springs and the soil resistance by external non-linear springs. Each spring has 2 stiffness in vertical/lateral deformations which is defined by t-z curve (or p-y curve) - a force-deformation curve. To develop the t-z or p-y curve you may use the program or manually iteratively calculate using theory presented in

"Pile Foundations in Engineering Practice" by Prakash & Sharma, Pubs:Wiley.
"Pile Design & Construction Practice" by Tomlison & Wodward, Pusb: Taylor & Francis (I think this forum has the link).

The above springs can be linear and nonlinear. However, linear is enough in design practice (exclude pushover analysis). In ETABS, linear model can be represented directly using spring support that connecting each rigid elements of a pile. Hence u just need to key-in the spring stiffness (calculate from t-z curve). Whilst, nonlinear model uses spring as zero-length element connecting each rigid elements of a pile. Then apply t-z or p-z curve for vertical and lateral rigidity whereas the rest of deformations assume in fixed condition.

That is general idea of soil-pile interaction. Sorry for lengthy words.
I hope it will help you and all of the reader regarding this topic.

Adekajeng