Question

If foundation block is supported by an elastic pad of contact area A and thickness t, the value of stiffness factor for vertical motion is given by which of the following expression?

(a) Kx = C A/t

(b) Kz = E A/t

(c) Kϴy = Ely / t

(d) All of the mentioned

I got this question in an online interview.

This key question is from Dynamic Analysis of Block Foundations topic in division Machine Foundations of Geotechnical Engineering II

Answer 1

Right option is (b) Kz = E A/t

To elaborate: The value of stiffness factors are given by the following expressions:

For vertical motion: Kz = E A /t

For horizontal (sliding motion): Kx = CA /t

For rocking motion: Kϴy = Ely/t.