부산대학교 도서관

A combinational optimization algorithm for the design of base-isolation devices (bearings and dampers) is proposed. Among multiple-type options in the devices, rational combinations with bearing and dampers are designed by applying the local search approach in the algorithm. The bearing sizes and numbers of dampers in addition to the device-types are treated as discrete design variables. For given structural conditions of superstructures, the total cost of the devices is minimized under the multiple constraints such as the maximum displacements in the isolation layers and floor accelerations in the superstructures. The responses under large earthquakes are simulated with multiple degree of freedom (MDOF) models of the superstructures in the response history analyses (RHA). The multiple Level 3 earthquake ground motions, which are recorded ground motions scaled and normalized as the maximum velocity of 75 kine, are used in RHA. The effects by higher modes are directly evaluated in RHA. The findings are as follows: