Seismic performance evaluation of steel frame structures equipped with tuned liquid dampers

Abstract

An economical solution to reduce building motions to an acceptable level, under dynamic loadings, is to provide additional damping. A passive damping device shown to be effective as a vibration control mechanism is tuned liquid damper (TLD). A TLD is a passive control system which utilizes fluid-sloshing motion to dissipate the lateral excitation energy. In this paper, the TLD was modeled as an equivalent nonlinear-tuned mass damper. Furthermore, the validity of the numerical procedure in predicting the structural response equipped with TLD under seismic loading is also investigated with two studies. To study the effectiveness of implementing TLDs, three existing intermediate steel moment-resisting frames were taken into consideration, and nonlinear response history analysis was carried out for structural models with and without TLDs. It was observed that TLDs can be utilized as seismic response mitigation devices and can also be employed for seismic rehabilitation of the existing steel structures. Even though the natural frequency of the TLD is always chosen to match the natural frequency of the structure, any change in the frequency of the primary structure or amplitude-dependent frequency of the TLD results in a detuned TLD system. Therefore, this paper also evaluates the efficiency of a detuned TLD system for some tuning ratios (0.8–1.2) by sensitivity analysis. The results showed that tuning ratio in the range of 0.9–1.1 has a slight influence on the seismic response of the structure.