Optimal Placement of Multiple Tune Mass Dampers for Seismic Structures

Effects of a tuned mass damper on the modal responses of a six-story building structure are studied first to demonstrate the damper's ineffectiveness in seismic applications. Multistage and multimode tuned mass dampers are then introduced. Several optimal location indices are defined based on intuitive reasoning, and a sequential procedure is proposed for practical design and placement of the dampers in seismically excited building structures. The proposed procedure is applied to place the dampers on the floors of the six-story building for maximum reduction of the accelerations under a stochastic seismic load and 13 earthquake records. Numerical results show that the multiple dampers can effectively reduce the acceleration of the uncontrolled structure by 10–25% more than a single damper. Time-history analyses indicate that the multiple dampers weighing 3% of total structural weight can reduce the floor acceleration up to 40%. The multiple dampers can even suppress the peak of acceleration responses due to impulsive excitations, which a single damper of equal mass cannot achieve.