Seismic control of mid-rise building using sealed tuned liquid column damper and compliant liquid column damper: a comparative study

In tuned liquid column dampers (TLCDs), the liquid column length is adjusted to tune the damper frequency to the structural frequency. For low- and mid-rise buildings, which have relatively shorter time periods, the liquid column length obtained for the tuning requirement becomes very small, and a realistic design of TLCD is not possible. This prompted the emergence of several improvised configurations of the TLCD. The prominent among them are the sealed TLCD (STLCD) and the compliant tuned liquid column (CLCD), both of which can be tuned to the natural period of typical mid-rise buildings. However, a detailed comparison of their performance in suppressing the seismic vibration of mid-rise buildings is missing in the current literature. The present paper endeavors to bridge the gap. In this paper, the basic working mechanism of the said two variations of the TLCD is elaborated. For numerical illustration, an example mid-rise building is analyzed. A three-dimensional STAAD.Pro model of the building is developed to determine the modal parameters associated with its fundamental natural mode. Based on these results, an equivalent single-degree-of-freedom (SDOF) structural system is derived. The equations governing the motion of the SDOF structure, along with STLCD and CLCD, are described. The effectiveness of the STLCD and the CLCD, having identical mass ratios, in mitigating seismic vibrations of the structure is evaluated using six recorded ground motions. Two cases of the CLCD are considered: (i) CLCD1, in which the effect of the dashpot element is neglected and the mass ratio is calculated based on the combined mass of the liquid and the damper container; and (ii) CLCD2, in which the effect of the dashpot element is considered and the mass ratio is calculated based on only the liquid mass. The results indicate that the CLCD1 achieves lesser structural response reductions as compared to STLCD. However, the CLCD2 outperforms the STLCD in most of the response indicators. Further, the performance both STLCD and CLCD2 are comparable to those achieved by a TMD having identical mass ratio.