Seismic response of buildings with energy dissipating systems built in soft soils

A parametric study of buildings retrofitted with metallic yielding energy dissipation devices built on soft soil sites is presented. Buildings with 6, 15 and 30 stories are analyzed as representative of low-, mid- and high-rise buildings. Emphasis is placed on parameters controlling the strength and stiffness of the structure and energy dissipation devices. Response history analyses are performed using narrow band ground motions representative of typical motions in very soft soil sites. It is shown that the seismic response is strongly influenced by the ratio of the inter-story stiffness in the frame to the inter-story stiffness of the energy dissipation device support framing system and by the ratio of fundamental period of the structure to predominant period of the ground motion.