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The application of fuzzy algorithms in the response control of a base isolated building with MR dampers is investigated in this

paper. Most of the previous researches in this field have been focused on fuzzy algorithms with linear membership function

however in the current study the membership functions are assumed to be Gaussian and their effectiveness is studied. For this

purpose, an eight-story building with regularity in plan and height is considered. The adopted base isolation system includes

linear bearings and control devices for improving the behavior of isolated structure under near field ground motions. MR

dampers are used to reduce base displacements and have the capacity of 1000 kN with the maximum applied voltage of 10 V. In

order to verify the control procedure and analyzing the structure, a simulation procedure is developed. This procedure performs

linear analysis of the structure in presence or in absence of the base isolation system. Moreover, the simulation procedure is able

to appropriately determine the MR damper voltage using fuzzy logic algorithms and then analyzing the whole system too. Finally,

seven near-field earthquake records are chosen in order to study the structure responses under these records and the obtained

results demonstrate the accuracy of proposed control procedure

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An important factor in the design and implementation of structural control strategies is the number and placement of actuators. By employing optimally-located actuators, the effectiveness of control system increases, while with an optimal number of actuators, an acceptable level of performance can be achieved with fewer actuators. The method proposed in this paper, simultaneously determines the number and location of actuators, installed in a building, in an optimal sense. In particular, a genetic algorithm which minimizes a suitably defined structural damage index is introduced and applied to a well-known nonlinear model of a 20-story benchmark building. It is shown in the paper that an equal damage protection, compared to the work of other researchers, can be achieved with fewer numbers of optimally placed actuators. This result can be important from economic point of view. However, the attempt to minimize one performance index has negative effect on the others. To cope with this problem to some extent, the proposed genetic methodology has been modified to be applied in a multi-objective optimization problem.

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Critical non-structural equipments, including life-saving equipment in hospitals, circuit breakers, computers, high technology instrumentations, etc., are vulnerable to strong earthquakes, and the failure of these equipments may result in a heavy economic loss. To guarantee function of vulnerable equipment during earthquake peak acceleration and peak base displacement response of system should be limited to allowable levels. Traditional and passive control strategies cannot afford these contradictory targets in same time for broad range of ground motions. In recent years, semi-active control systems have been introduced as an adaptable and reliable alternative to control response under both limitations with low power supply. In this paper, efficacy of smart semi-active controlled floor isolation system which consists of a rolling pendulum system and a semi-active controlled magnetorheological (MR)-damper to control seismic response of equipment has been investigated by using clipped-H_2/LQG and clipped-H_∞ algorithms. The effectiveness of these algorithms was examined for equipment stand on raised floor due to floor motions in seven stories building. The results demonstrate semi-active control effectively decrease response acceleration and velocity of equipment in compare to passive strategy and hold its relative displacement to floor in least value. Furthermore it was shown semi-active control strategy with clipped-H_∞ algorithm in controlling seismic response of equipment compare to clipped-H_2/LQG algorithm and passive strategy (isolation system) have better performance in protecting equipment.