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.