Soil-structure interaction

[David kharanauli]

Hi there,
Here is my question: Do engineers use soil - spring supports for buildings, under foundation, when they analyze buildings in FEA software, in USA and Europe or Not? in my country (Georgia) we always use that method to consider soil stiffness, and we design building and its foundation in one FEA model. As I made research about that I found next: Most of people design buildings in two separate model , one model is only building without foundation and with rigid restrains below columns, and second model is only foundation (that would be another software). If you have any references about that topic share with me.

 

[EireChch]

I think the issue is when you use a combined structural and geotechnical model it usually in a structural type software with springs being lineally elastic.

Obviously soil is the complete opposite of linearly elastic.

But in saying that, a combined model with appropriately conservative springs is not a bad approach at all.

 

[ggcdn]

We sometimes use them, but most often not. The biggest hurdle is that we usually want to do dynamic analysis (modal response spectrum analysis) which can only use a linear spring. When subjected to overturning, the footing puts a bunch of springs in tension which is an unrealistic scenario.

I prefer a separate foundation model (in SAFE for example) with compression only springs, and a nonlinear static analysis of the governing load cases.

-JA
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