An Experimental Study of Tuned Mass Damper to Control the Vibration of Concrete Floors |

ABSTRACT:

Currenttrends in construction industry demands taller and lighter structures, which arealso more flexible and having quite low damping value. This increases failurepossibilities and also problems from serviceability point of view. Now-a-daysseveral techniques are available to minimize the vibration of the structure,out of the several techniques available for vibration control, concept of usingTMD is a newer one. This study was made to study the effectiveness of using TMDfor controlling vibration of structure. At first a numerical algorithm wasdeveloped to investigate the response of a shear building fitted with a TMD.Then another numerical algorithm was developed to investigate the response of a2D frame model fitted with a TMD. A total of three loading conditions wereapplied at the base of the structure. First one was a sinusoidal loading, thesecond one was corresponding to compatible time history as per spectra ofIS-1894 (Part -1):2002 for 5% damping at rocky soil with (PGA = 1g) and thethird one was 1940 El Centro Earthquake record with (PGA = 0.313g). Fromthe study it was found that, TMD can be effectively used for vibration controlof structures. TMD was more effective when damping ratio of the structure isless. Gradually increasing the mass ratio of the TMD results in gradualdecrement in the displacement response of the structure. Thispaper deals with the optimum design of a tuned mass damper (TMD) for themitigation of machineinducedertical vibration of structures. Theoretically, aTMD without damping tuning to the machine operating frequency will make optimumcontrol performance. Considering zero damping is impossible, a new field-baseddesign procedure and an adjustable vertically moving TMD (VTMD) are proposed.The VTMD is composed of variable mass blocks and changeable springs. Aprototype of the VTMD was fabricated and tested on a simply supported beam anda reinforced-concrete floor of a school building. Both experimental resultsconfirmed the control effectiveness and usefulness of the VTMD. Highlevels of unwanted vibrations are normally occur in light, and (or) long spanfloor systems due to human activities such as walking or jumping. It causesannoyance and discomfort to the occupants. Hence, rectification measures wouldbe required to minimize floor vibrational displacement amplitudes. This work isconcerned with the development of a new innovative passive viscoelastic fourarms damper. The mission of this damper is to reduce floor vibration.