Strengthening a tube connected building group by base isolators and story isolators

Seismic isolation systems have been used to retrofit existing buildings. However seldom studies have focused on retrofit existing building groups by isolation system. This study uses base isolation technologies and story isolators to retrofit an existing tube connected building group. Base isolators are designed to protect the frames from strong earthquakes. Story isolators are chosen to provide lateral resistance and dissipate energies from serious earthquakes. Equations of motion are formulated to study the responses of the new building system to strong earthquake motions. Simulation results show the maximum drifts of the tubes and the maximum drifts of frame are very small. Maximum relative displacement between the tube and frame is much less than the seismic joint limit.