BASE ISOLATION STRUCTURE

To provide a base isolation structure capable of exerting damping performance and base isolation performance regardless of earthquake magnitude scales.SOLUTION: A base isolation structure has: a lower structure 20; a base isolation device placed on the lower structure 20; an upper structure 30 supported by the base isolation device; and a collision shock absorbing material (fender 80) deformed by being pressed from the lower structure 20 or the upper structure 30 when the lower structure 20 and the upper structure 30 are relatively displaced and the lower structure 20 or the upper structure 30 is brought into contact therewith. The base isolation device has: a first base isolation device (base isolation device 40) including a first support portion (lead plug 42, laminated rubber 44) deformed by external force and damping vibration, and a slide mechanism (slide material 46, slide plate 48) for sliding and displacing the first support portion; and a second base isolation device (base isolation device 50) including a second support portion (lead plug 52, laminated rubber 54) deformed by external force and damping vibration, and not including the slide mechanism.SELECTED DRAWING: Figure 1 【課題】地震の規模に関わらず減衰性能と免震性能とを発揮できる免震構造を提供する。【解決手段】免震構造は、下部構造体２０と、下部構造体２０に載置された免震装置と、免震装置に支持された上部構造体３０と、下部構造体２０と上部構造体３０とが相対変位して下部構造体２０又は上部構造体３０が当たった際に下部構造体２０又は上部構造体３０から押圧され変形し振動を減衰する衝突緩衝材（防舷材８０）と、を有し、免震装置は、外力によって変形して振動を減衰する第１支承部（鉛プラグ４２、積層ゴム４４）と、第１支承部を滑り変位させる滑り機構（滑り材４６、滑り板４８）と、を備えた第１免震装置（免震装置４０）と、外力によって変形して振動を減衰する第２支承部（鉛プラグ５２、積層ゴム５４）を備え、滑り機構を備えない第２免震装置（免視装置５０）と、を有する。【選択図】図１