Semi Active Control

Abstract—Natural hazards such as earthquake occur often and damage the civil structure across the world. Collapse of building is due to the vibrations that occur during the earthquake. One such technique to establish effective structural control is base isolation system. It prevents the collapse of structure but not the contents present in it. To ensure the safety of building and its contents semi active control strategy has to be established. Semi active control of base isolated structure consists of friction pendulum bearing as passive isolators at the base with controllable semi active devices. Semi active actuators such as MR dampers are controlled by designing the PID controller due to its simplicity and effectiveness. Performance of the

It is a disruptive disturbance that causes shaking of the surface of the earth due to underground movement along a fault plane or from volcanic activity. In-order to avoid the damages caused by the earthquake, civil structure is provided with base isolators. The concept of base isolation has been an active research area for about three decades which tend to resist the seismic excitation passaging from ground into the civil structure. Lead rubber bearings and friction pendulum bearings are the non-linear isolation devices mounted in between the super-structure and its foundation. Base isolation system reduces the seismic response in the super structure but with increased base displacements. In this work benchmark hysteretic base isolated building in Los Angeles, California is taken for the performance analysis of structure response during earthquake excitation. Sample earthquake data set that has been taken to analyze the base isolated structure is Newhall, Sylmar, El Centro, Rinaldi, Kobe, Jiji, Erzinkan. The base-isolated structure behaves as an elastic medium, so whenever the earthquake occur isolators displaces depending on the ground movement. Hence the seismic waves are arrested at isolation level itself. However, due to the elongation of isolators at the base alters the position of contents present in the structure. In fixed base, the structure would

In general, structures with longer periods of vibration tend to reduce acceleration, while those with shorter periods tend to increase or amplify acceleration. The smart base-isolated benchmark problem was developed [5], based on input from the ASCE (American Society of Civil Engineers) structural control committee. In this control problem, three different types of isolation bearings such as elastomeric bearings, lead rubber bearings, and friction pendulum bearings have been modeled along with the actuators. Actuators may be either active or semi active devices. These flexibilities were made to invite more number of researchers to develop different control algorithm for effective reduction of seismic