Dynamic Responses of Core-Tubes with Semi-Flexible Suspension Systems Linked by Viscoelastic Dampers under Earthquake Excitation

Abstract

A new configuration of Core-tubes with Semi-Flexible Suspension Systems (CSFSS) is presented in this paper. This structure is composed of the primary core-tube, suspended segments regarded as suspension systems, viscoelastic dampers and flexible layers. The configuration, simplified model and the formulation of the multi-degrees of freedom equations of motion for this structure are given. The El Centro 1940 and Kobe 1995 earthquake time histories were employed for dynamic analysis of the system in the time domain. Random seismic response is determined by the complex mode superposition method. Based on the derived formulas, a computer program has been developed and parametric studies, such as the locations of the flexible suspended segment, the damping coefficient and stiffness of viscoelastic dampers, were performed to evaluate the vibration-absorption effectiveness of the primary core-tube, and to identify optimal parameters for the damping devices. Results show that this configuration can reduce seismic responses in the central core-tube and has a larger inter-storey drift in its flexible layers but less inter-storey drift in its suspended segments. Furthermore, there is an optimal damper damping coefficient that leads to a minimum response of the primary core-tube, and the flexible suspended segment located at the top can effectively reduce the earthquake-induced responses of the core-tube.