Tuned liquid damper for vibration mitigation of seismic-excited structures on soft soil

Abstract

The study aims to investigate the potential of using a tuned liquid damper (TLD) as a mitigation measure to reduce the seismic responses of structures on soft soil. Damping screens are installed in the TLD, as a flow damping device (FDD), to enhance the energy dissipation capacity. An equivalent impulsive and convective masses model is utilized to simulate fluid-tank interaction, while the cone model is adopted to simulate the soil beneath the supporting foundations. The governing equations of motion of the structure-TLD-FDD system under earthquake excitation considering soil-structure interaction (SSI) are formulated and solved using the discrete-time state-space approach. Sensitivity analyses were performed to assess the mitigation effects by varying the important parameters in terms of soil types, fundamental periods of structures, mass and frequency ratio of TLD, and earthquake peak ground accelerations (PGA) levels. Numerical results clearly indicate that the inclusion of SSI increases seismic demand as well as considerable change in building’s behaviour. In addition, findings reveal that attaching a roof water tank substantially improves the seismic performance of flexible base buildings. Finally, the efficiency of TLD in mitigating the dynamic responses depends not only on the characteristics of the TLD employed, but also on the supporting soil.