Abstract:
This study presents modified versions of tuned liquid column ball damper (TLCBD) known as tuned liquid column ball spring sliding damper (TLCBSSD) and tuned liquid column ball spring rolling damper (TLCBSRD). In these modified versions the ball inside the horizontal section of the damper has been attached with spring. In TLCBSSD the ball attached with spring can translate only. While in TLCBSRD the ball attached with spring can translate as well as rotate. Mathematical models and optimum design parameters are formulated for both types. The performance of these new modified damper versions is assessed numerically and subjected to harmonic, seismic, and impulse loadings. The results show that the performance of the newly proposed dampers is relatively better than traditional TLCBDs in harmonic and seismic excitations. After numerical study, for experimental validation a series of shake table testing are performed. Both the dampers’ performance has been evaluated on 4 story frame structure under harmonic and seismic excitations. The damper was placed on the top of the fourth story in each experimental setup. The RMS acceleration, displacement, and inter-story drift of each story have been calculated at harmonic and seismic loadings for uncontrolled structure, structure with TLCBD, with TLCBSSD, and with TLCBSRD. Compared to uncontrolled structure both TLCBSSD and TLCBSRD reduced the RMS response of the structure at resonant and seismic excitations. At harmonic loadings including frequency 0.65 Hz, 1.17 Hz, 1.30 Hz, 1.43 Hz, and 1.95 Hz, the RMS responses of the structure with TLCBSSD and TLCBSRD have been reduced against structure with TLCBD. The maximum reduction in the responses of TLCBSSD and TLCBSRD over TLCBD has been observed at resonant loading. Moreover, at seismic loading, the decrease in the RMS responses with TLCBSSD and TLCBSRD over TLCBD is slightly lesser than reduction efficiency at resonant loading. Overall, the performance of TLCBSSD and TLCBSRD is outstanding than the performance of TLCBD under both harmonic and seismic loadings.
