Role of Liquid Tuned Mass Dampers in Improving Torsional Competence of Asymmetric Buildings

Abstract

The development of urban environment is reflected by the increase in tall structures. These structures are highly vulnerable of lateral forces caused by different kinds of natural calamities. To counter their effect on structures, many types of structural elements like shear walls, infill frames etc., are tried over a period of time. But, their inclusion is often unacceptable, besides the cost escalation. In this backdrop, tuned mass dampers are tried as the most viable the alternatives to shear walls.  Many types of tuned mass damper systems are explored as on date. Currently, the concept of liquid tuned mass dampers as TMDs is attracting wide research interest as it is an integral part of structural system, go well with the architectural features of the building and do not cause much cost escalation. Modelling the overhead water tank in a building as liquid tuned mass dampers would significantly reduce the amplitude of vibration and the maximum base shear in a building when subjected lateral disturbances. 

A Tuned Mass Damper (TMD) is a device consisting of a mass and spring that is attached to a structure in order to reduce the dynamic response of the structure. The frequency of the damper is tuned to a particular structural frequency so that when that frequency is excited, the damper will resonate out of phase with the structural motion. The Tuned Liquid Mass Damper (TLMD) is modeled with the help of overhead water tanks which form an integral part of the building. These tanks while serving the purpose of storing water, would also meet the requirements desirable of a tuned mass damper. The structural effectiveness of building with and without TLMD is presented by carrying-out the structural analysis using both Response Spectrum Method and Linear Time History Analysis. The performance of the tuned liquid mass dampers is demonstrated by comparing the values of Maximum Story Deflection and the magnitudes of Base shear of the building for different tank capacities. The study is proposed to be carried out on an RC building with plan asymmetry, located in a highly seismic active region using ETABS.