Interesting .....

You still don't give much information about your modeling and what you are trying to accomplish. For example, why are you using a nonlinear link property instead of the linear link which offers springs and dampers? Is it important to consider nonlinear P-Y T-Z values? For pile analysis I could see that being a concern, but for building foundation analysis it's probably unnecessary in most designs. What are trying to accomplish by choosing the nonlinear link option?

You can assign links, both linear and nonlinear links to areas, either solid or shell areas, by utilizing the "Property is defined for this area in area and solid springs" multiplier which is on each link dialogue. Since your foundation is pile supported, then you need to model the piles using frame elements and then assign springs or links to joints along the length of the pile.

Soil can be modeled using solid finite elements with the appropriate material property values for the soil. The following link may gives you further explanation http://www.edwilson.org/BOOK-Wilson/16-SSI.pdf

Thanks alot for your generous reply :), and yes i am concerned with the soil behavior so the (p-y) curves is recommended.

i used nonlinear area links or springs for the wall but i leave this multiplier to its default value (=1) should i modify it to be equal the area of each shell say (=0.5*0.5)? .

and for the pile i used also a nonlinear frame/line spring, having the line multiplier also (=1) , although the pile is a frame element which is divided into lines of 0.6 m length.

In the linear case, i used an effective stiffness equals that of the soil multiplied by the depth of each spring. when the load case is set to be linear, i got a reasonable results. but when it is set to be nonlinear case with the default nonlinear parameters (as depicted in the attachment), the displacements are so large that i think it reaches the ultimate load of the (p-y) curve so the resultant moment is linear (i don't know may be there is something in the parameters should be modified or i missed any thing while running this nonlinear case)

You are welcome, I hoe it was useful to you.

Yes, you should apply the actual values (not default values). It is logic that default values gives better results for linear cases compared to nonlinear cases.

Good luck

Maha Yasseen

Thank you Dr.Boris Folic , your research was really helpful. i applied the NSA and i got the right moment diaghram, but the values was large at the top of pile (=14 t.m) while it should be about 3 t.m.

Thanks again Dr. Boris Folic , Now everything is okay, i can't express my gratitude

HAI Maha Yasseen

I AM ALSO DOING MY RESEARCH ON SOIL STRUCTURE INTERACTION ON PILE FOUNDATION CAN YOU EXPLAIN HOW TO ASSIGN HINGE PROPERTIES TO PILE FOUNDATION.