EFFECT OF TUNED MASS DAMPER AND MULTIPLE TUNED MASS DAMPER ON THE VIBRATION OF CHIMNEY SUBJECTED TO SEISMIC LOAD

The number of low and light structures daily is steadily increasing in the construction industry with flexible and very low braking values. Reinforced Concrete (RC) chimneys are widely used in industry. Strong winds and earthquakes damaged many industrial chimneys around the world. The performance of RC chimneys under dynamic loading is well documented by many researchers. Tuned Mass Dumper (TMD) is a passive energy device used to reduce unwanted vibrations in many structural or structural components. There are few studies on the effects of TMD and MTMD to reduce the effects of chimney seismic events. This paper investigates the effect of a mass damper adjusted for the response of chimneys in seismic excavation. Combined differential equations of motion for chimneys and TMD are derived and solved using Newmark's integration method. The optimal location of the TMD and MTMD is identified by the mode type of the uncontrolled chimney. A TMD is placed where the mode shape amplitude of the chimney is the larger in a fundamental mode and is tuned with the corresponding fundamental modal frequency. The reduction was dependent on the TMD properties, location and optimum properties of the damper. A parametric study is conducted to find the most suitable mass ratio and damping ratio for all cases. The research findings indicate that the MTMDs are more effective than the STMD Keywords— Chimney, TMD, MTMDs, Earthquake, Modal frequency/shape, Multi-mode control, Tuned mass damper