ACTIVE VIBRATION CONTROL OF STRUCTURES AGAINST EARTHQUAKES USING MODERN CONTROL THEORY

Structural control against earthquakes is becoming increasingly important. The linearquadratic optimal control algorithm is proposed here to design active control system for buildings against earthquake excitations. Full-state feedback system has been adopted. Active Tuned Mass Damper is used as the control mechanism. The efficiency of the designed system has been verified against El-Centro earthquake. Active control gives 35% more reduction in vibration of the structure than passive control. Mass of the damper has appreciable effects on response parameters than its stiffness. A flexible damper proves to be more effective, but at the cost of actuating forces required. Performance of system is found to be optimum, when mass-damper is tuned to fundamental frequency of the structure. Stability of the structure is also enhanced by Active Control system. A SDOF building is presented to illustrate the study.