| 摘要 |
PROBLEM TO BE SOLVED: To achieve the superior base isolation effect to both of the big and smal earthquakes by comprising a first laminated rubber of which the upper and lower ends are fixed to the upper and lower structures and a second laminated rubber surrounding the first laminated rubber, and making an upper end of the second laminated rubber slidable or rotatable within a specific range. SOLUTION: This base isolation device 1 comprises a second cylindrical laminated rubber comprising a through hole on its almost center, and a first cylindrical laminated rubber 14 mounted in the through hole with a gap, and lower portions of both laminated rubbers 14, 16 are fixed to a lower plate 17 fixed by a bolt. The upper portions of both laminated rubbers 14, 16 are mounted in such manner that an upper end of the second laminated rubber 16 is slidably or rotatably fitted to a recessed part 12b of a lower face of an upper plate 12 which is fixed to a lower face of an upper slab 10 by a bolt. A diameter of the first laminated rubber 14 is determined so that it is sheared and deformed in the comparatively small earthquake, and a cross sectional area of the second laminated rubber 16 is determined so that it is sheared and deformed in the comparatively large earthquake. |
