Study of soil-structure-tuned liquid damper interaction

Recently a new type of damper, termed a tuned liquid damper (TLD), which relies on the sloshing of liquid in a rectangular tank has been introduced to enhance the dynamic performance of lightly damped structures. The objective of this study is to experimentally investigate the effect of soil-structure interaction on the performance of TLDs. A five-storey model building was mounted to a shake table to simulate a fixed base condition, and subjected to white noise base acceleration to determine its dynamic response characteristics. In order to simulate the foundation flexibility, two urethane foundation blocks were used, one to represent a soft soil, the other to represent a stiff soil. A comparative study was conducted on the effectiveness of a TLD, in reducing the structure's dynamic response. This was accomplished by first tuning the TLD to the first natural mode of the fixed base structure, and then to the first natural frequency of the soil-structure system, accounting for the foundation flexibility. The results indicated that soil-structure interaction drastically modified the structural system's response to dynamic excitation. It was found that the largest reduction in dynamic response of the structure occurred when the TLD was tuned to the frequency of the system, which included the effects of soil-structure interaction.