Seismic Response Control of Structures with Stiffness Irregularities through Optimally Placed Active Tendons using Multiobjective Genetic Algorithm

This paper studied the seismic response control of structural building with stiffness irregularities through active tendon system (ATS) using Linear Quadratic Regulator control algorithm. The various responses considered are the floor displacements, story drifts, and base shear. The optimal number and the optimal position of these active tendons are obtained through multiobjective optimization using Genetic Algorithm to reduce the responses and the cost of the control system simultaneously. The conflicting objectives minimized are the base shear of the irregular building and the number of active tendons to be used. The maximum story drift and maximum floor displacement are used as constraints. For numerical results, six combinations of stiffness irregularity in critical storys 1,2,and 10 of a ten story defecient shear building frame subjected to El Centro earthquake is considered. The results show that the optimized control system is capable of keeping the responses of the building frame to an earthquake within permissible limits and stiffness irregularity in the same defecient frame cost only the tendon in atmost one additional story.