Optimal Design of Base‐Isolated Structures with Dynamic Absorbers

Abstract

In this study, a passive control system has been proposed to protect structures from earthquake damages. In particular, the influence of an absorber on the dynamics of base‐isolated structures has been investigated in detail. Two different types of base‐isolation systems have been considered. These include rubber‐bearing and sliding‐friction isolators. The base isolators are represented by hysteretic models. The absorber consists of a linear spring mass attached to the base. Simulation studies were conducted for various models subjected to the 1971 San Fernando earthquake excitation. An optimization subroutine based on the simplex method was utilized to determine the best absorber parameters for a given situation. It is concluded that the base isolators can be much more effective in protecting conventional structures from earthquake damages if they are used in conjunction with an absorber. The optimum mass of these absorbers is found to be quite small as compared to the mass of the ground structures. It is anticipated that the results obtained in this study could be put in practice in the near future and serve as a meaningful design technique in preventing earthquake damages.