tvs
Structural
- Sep 10, 2000
- 6
I am analysing a storage tank for seismic loading. I have modelled foundation using discrete spring and mass elements following elastic half space theory. I have calculated the stiffness, damping and mass values following Newmark's book 'Fundamentals of Earthquake Engineering'. I have read in another book (Static and Dyanamic Analysis by Wilson) that the effective earthquake forces must not be applied to the foundation mass. I haven't understood this issue completely. Can anyone suggest how to consider the added mass of the foundation (I guess this is simply a fictitious mass which indirectly takes into account the inertial effect of foundation). I understand that some codes give factors to modify static stiffness value (especially the rocking stiffness) to make it frequency dependent. Is it adequate to model the soil with modified static stiffness and ignore the mass altogether?
