Rotating semi-active tuned liquid column damper for bi-directional eccentric structural seismic response control

To mitigate the translational-torsional coupling response of bi-directional eccentric buildings under seismic excitations and improve the earthquake mitigation of traditional tuned liquid column damper (TLCD), a rotating semi-active TLCD (RS-TLCD) with variable hydrostatic liquid level height and frequency, damping and rotating angle that can simultaneously control the bi-directional vibration of structures is proposed. RS-TLCD can identify the bi-directional instantaneous vibration frequency of structure through wavelet transform, and change the height of liquid column in real time to adjust its natural frequency accordingly. Meanwhile, it can change the size of adjustable flow hole to achieve real-time semi-active damping based on measured signals, while use a rotating chassis to achieve real-time adjustment of the position angle in the plane to the dominant vibration direction, to achieve bi-directional vibration control. In the case study, a 30-story bi-directional eccentric structure is presented to verify its seismic control effect, and cases with unidirectional passive TLCDs and S-TLCDs attached in X and Y directions are compared respectively. Numerical results show that generally, RS-TLCD can effectively control the displacement and torsional response of building under earthquake excitations to improve its safety and has the best earthquake mitigation performance in both X and Y directions. Meanwhile, RS-TLCD can reduce the mass of damper and the occupation of the building space because it can rotate the position angle to the dominant vibration direction, and enhance the control effect through variable liquid level height and damping.