A design method of a base isolated system for detached houses using variable oil dampers

In this paper, we propose a design method to contral the displacemeiit of base-isolation layer using an oil damper that can change its damping coefficient relative to the displacement. The present damping rovides largc damping to reduce Lhe responsce displacement of the base-isolation layer in severe or extreme seismic events, where it prnvides small damping to reduce the response acceleration of the superstructure in moderate seismic events. A numeical optimization method. sequential quadratic progranning is employed to obtain an otimum set of parameters for the present. damper. Design examplesshaw that the base-isolatiot system with oil optimallydesigned vaiable oil damper satisfy the design ciiciia iat canit be satisfied with a system incoroiating a conventionaI oil damper.