Study of a Semi-Active Control System to Reduce Lateral Displacement in Framed Structures under Seismic Load

Abstract

This study presents the numerical implementation of a semi-active control system used to reduce lateral displacements in framed structures under seismic loads. To manage forces in the structures, two controllable fluid devices called magnetorheological (MR) dampers were used, and a fuzzy logic (FL) algorithm was employed to determine the optimal control forces. The FL controller has been programmed based on a set of 49 inference rules using two input parameters: displacement and velocity of the first story of the uncontrolled structure. The voltage to be applied to the MR dampers was the output parameter of the control algorithm, thus altering the damping forces in the system. To evaluate the performance of the proposed controller, three plane frame structures with different geometric configurations were modeled and subjected to four different real ground accelerations records. The results obtained in this study showed considerable reductions in displacement, acceleration, and interstory drift for all the structures studied, demonstrating the effectiveness and efficiency of the controller to improve the damping characteristics in structures.