An experimental study of tuned liquid column damper controlled multi-degree of freedom structure subject to harmonic and seismic excitations

Abstract

A tuned liquid column damper (TLCD) is a passive vibration control device that not only mitigates unwanted structural vibrations but also acts as a water storage facility in a building. These aspects of TLCD make its application specifically suited for building structures. Previously, many experimental works on TLCDs have been conducted considering a single degree of freedom (SDOF) structure. However, the performance of TLCDs to control the response of multi-degree of freedom (MDOF) structure has rarely been studied experimentally. Therefore, this study has investigated the performance of a tuned liquid column damper (TLCD) on a multi-degree of freedom (MDOF) structure using shake table testing. A four-storey steel frame structure equipped with TLCD at the top of the fourth storey has been studied. Experimental normalized frequency response curves for MDOF structure equipped with TLCD have been determined. For this purpose, a series of harmonic loadings including frequencies 0.65 Hz, 1.17 Hz, 1.30 Hz, 1.43 Hz and 1.95 Hz have been applied in addition to historic earthquake loading. Peak and root-mean-square (RMS) accelerations have been discussed in detail for all the applied loadings at each storey level of the structure. For comparison purposes, the percentage reductions in peak and RMS accelerations have been calculated and compared. Also, RMS displacements and inter-storey drifts have been presented for resonant and seismic excitations. Both in time and frequency domains, responses of controlled MDOF structure have been analyzed and compared with uncontrolled structure. Results confirmed that TLCD has improved the MDOF structure responses at harmonic loadings frequencies near resonance and historic earthquake excitations. Furthermore, the improvement in the responses of MDOF structure with TLCD is more prominent at harmonic loadings compared to historic earthquake loading.

Analytical Model of Structural Damping in Friction Module of Shell Shock Absorber Connected to Spring

“…Ten, based on formulas ( 14), ( 15), ( 17), ( 23), (24), and (28), we obtain the hysteresis loop equation in implicit form (dependences of δ on…”

“…Formula (23) gives us a nonlinear relationship between piston displacement and loading. Toward the end of the unloading stage, one-sided sliding is achieved on the contact surfaces (Figure 6), and formula (24) indicates that the unloading section of the deformation diagram will always end in a straight line.…”

“…Separately, it is necessary to pay attention to vibrationdampening systems in the construction industry. High-rise structures are vulnerable to structural vibrations induced by wind and earthquake loadings [24]. Passive-tuned mass and liquid dampers are a popular choice among structural vibration control systems for being reliable, economical, and easy to implement [25].…”

Developed steady-state response for a new hybrid damper mounted on structures

“…Now by introducing the foregoing boundary conditions to Eqs ( 4) & ( 7), taking π 1 = π/β, and substituting t 4 = t 2 +π/ω f in Eq (8), the below equations arise:…”

“…Supplementary dampers are artificial energy dissipators that increase the total structural damping, reduce the structural response to external vibrations and contribute to structure resistance against severe translations. Various damping mechanisms such as the viscous dampers [4], yielding dampers, magnetic dampers, tuned mass dampers, friction dampers [5] and tuned liquid dampers [6][7][8] are frequently applied in the newly built structures.…”