A conceptual study and fundamental characteristic tests on vertical seismic isolation system

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A vertical seismic isolation system is composed of coned disk springs and lead dampers, and it is planed to apply to the common-deck-isolation-system in the large scale FBR Plant. The design study on the isolation system has been carried out, and the behavior of coned disk springs are tested. The results are as follows. (1)The lead damper, which absorbs the seismic energy by its plastic deformation, is applicable in the isolation system. (2)The isolation system is very effective when the natural frequency is less than 2.5 Hz. The displacement and the acceleration response are not sensitive to damping coefficient of the isolation device. (3)The rocking response of the common deck is very small. (4)The connection device for each coned disc spring using 'Connection-Ring' are designed. (5)The matelial called "WEL-TEN" series are applicable for the coned disk spring of the isolation device.