A semi-active tuned liquid column damper for lateral vibration control of high-rise structures: Theory and experimental verification

This paper presents a new type of semi-active tuned liquid column damper (S-TLCD) for the lateral vibration control of high-rise civil engineering structures. Analogous to the passive tuned liquid column damper (TLCD), the S-TLCD comprises a U-shaped tank consisting of two vertical columns, which are arranged at a distance from each other and communicating through a horizontal passage. The tank is partially filled with a Newtonian fluid until the liquid reaches a certain level in the columns. In contrast to the passive TLCD, the S-TLCD provides also mechanisms for a continuous adaptation of both its natural frequency and damping behaviour in real-time. In the first part of the paper, the governing equations of the S-TLCD are derived based on the Bernoulli equation of a non-stationary incompressible liquid flow. The natural frequency of the S-TLCD is revealed to depend on the scaled length of the liquid. The scaling amount of the liquid length is formulated in dependence of the cross-sectional area ratios of the tank segments. The mathematical description of the S-TLCD is concluded by providing the state-space representation of a multi-degree-of-freedom structure with several S-TLCDs. In the second part of the paper, the derived natural frequency equation is verified and the proof of concept of the S-TLCD is shown by experimental investigations, which are performed on an S-TLCD model utilizing a test structure and shaking table tests.