Abstract
The seismic response of linearly elastic, idealized single-storey, one-way asymmetric building with semiactive magnetorheological (MR) dampers with clipped-optimal algorithm is investigated. The response is obtained by numerically solving the governing equations of motion. The effects of eccentricity ratio, uncoupled time period, and ratio of uncoupled torsional to lateral frequency are investigated on peak responses which include lateral, torsional and edge displacements and their acceleration counter parts, base shear, and control forces. To study the effectiveness of control system, the controlled response of asymmetric system is compared with the corresponding uncontrolled response. Further, controlled response of asymmetric system is compared with corresponding symmetric system to study the effects of torsional coupling. It is shown that the implementation of semiactive dampers reduces the deformations significantly. Also, the effects of torsional coupling on effectiveness of semiactive system are found to be more sensitive to the variation of eccentricity and torsional to lateral frequency ratio.
Highlights
Many times, most of the real structures are prone to the severe response and damage during a seismic event due to their asymmetric nature
It is important to note that the root mean square (RMS) control forces required for passive-on case is much more higher than the passive-off case while for the semiactive case it is only little higher than passive-off case. This reflects that, for the semiactive clipped-optimal control algorithm, with little increase in RMS damper forces as compared to passive-off case, the higher or comparable reduction in peak and RMS values of lateral, edge, and torsional responses is obtained than those which is obtained by passive-on case
For torsionally flexible and strongly coupled systems, the effects of torsional coupling can not be neglected while estimating the effectiveness of semiactive control system for asymmetric systems as compared to corresponding symmetric systems in controlling edge displacements
Summary
Most of the real structures are prone to the severe response and damage during a seismic event due to their asymmetric nature This asymmetry in the buildings arises primarily due to uneven distribution of mass and/or stiffness of the structural components for elastic range. Many researchers have investigated the performance of seismic control aspects of lateral-torsional deformations using various techniques such as passive control namely base isolation and supplemental dampers and active control. The above studies reflect the effectiveness of some of the semiactive systems in controlling the lateral-torsional responses, no specific study has been carried out to investigate the effects of torsional coupling especially by considering important system parameters on edge deformations as well as on control forces using semiactive MR dampers. The important parameters considered are eccentricity ratio of superstructure and uncoupled time period and ratio of uncoupled torsional to lateral frequency
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