A frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. In such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. With this in mi...

Code response spectrum models, which are used widely in the earthquake-resistant design of buildings, simple to apply but they do not necessarily represent real behavior an earthquake. A code model typically incorporates ground motion a diversity earthquake scenarios affecting site and does any specific scenario. The soil amplification phenomenon is also poorly represented, as current classific...