Non linear Lateral soil Spring
Non linear Lateral soil Spring
(OP)
I have a probolem in modelling the lateral soil spring.
To cater the yielding of soil (An upper bound of spring capacity), i believe i have to model the lateral soil spring with two bi-linear curves, is there any way i can make it in etabs?
Maany Thanks.
To cater the yielding of soil (An upper bound of spring capacity), i believe i have to model the lateral soil spring with two bi-linear curves, is there any way i can make it in etabs?
Maany Thanks.





RE: Non linear Lateral soil Spring
I never tried this, but by the principle of superposition of actions (therefore reactions) and starting from the hypothesis that the behavior has two linear domains, I find is reasonable to make the above assumption. If you get acceptable results, please let me know about this.
RE: Non linear Lateral soil Spring
May I know what the commands for the following steps
(i) how to define a spring with an upper limit of capacity?
(ii)when the first spring fail, and further the 2nd springs will become active?
I am a new user for ETABS. I may be not fully know every single command in ETABS.
Please advise
Thanks.
RE: Non linear Lateral soil Spring
I don't know how to define the upper limit of spring capacity either. For that, it would be needed a limit for displacement, upto which the law of variation applies and I don't know where can that be input (or if).
But, I thought of another way. It is not sophisticated, instead it may take some aditional time to model and analyze: use nonlinear hinge. This is what I thought of:
- define supports, like columns, with a separate material and input there elasticity modulus and strength of soil. Put dimension of supports such as to cover the full supported area
- go to define > frame nonlinear hinge properties and define a nonlinear hinge for AxialP (instead of using the default generated by ETABS, you can Modify/show for P the bilinear variation there)
- assign > frame line > frame nonlinear hinges > TheHinge to the supports (the columns defined as supports)
- define > static nonlinear/pushover case and add a case using your loads and afferent coefficients. Monitor on UZ a relevant point (like the location of a support)
- run the elastic analysis, then the static nonlinear analysis and Display > show static pushover curve for a graphically display of the effect of increasing load on the nonlinear behaving soil.
I advise to ask for a second opinion on this procedure. I have never verified its validity, but I hope it is useful for you. Please let me know if this works.