Semiactive seismic response control of buildings with podium structure

A multistory building with a large podium structure under earthquake excitation may suffer from whipping effect due to the sudden change of building lateral stiffness and mass at the top of the podium structure. An experimental investigation was carried out in this paper to explore the possibility of using magnetorheological (MR) dampers to connect the podium structure to the multistory building to prevent the whipping effect. The multistory building was constructed as a slender 12-story building model, whereas the podium structure was built as a relatively stiff three-story building model. A MR damper together with a current controller was used to link the three-story building to the 12-story building. The dynamic characteristics of the two buildings without any connection and with a rigid connection were first identified. The two building models without any connection and with the rigid connection were then tested under the scaled El Centro 1940 north-south ground motion. Finally, the two building models connected by the MR damper manipulated by a multilevel logic control algorithm were tested under the specified ground motion. The experimental results show that the MR damper with the multilevel logic control algorithm could significantly mitigate the seismic whipping effect and reduce the seismic responses of both the multistory building and podium structure.