| 摘要 |
PROBLEM TO BE SOLVED: To effectively avoid collapse of the whole structure by providing a cushioning part having cushioning function on the upper part of a cylindrical structure in the direction of the center axis, and cosuming earthquake energy by plastic deformation of the cushioning part. SOLUTION: A cushioning part 2 in detachable construction is provided on the upper part of a cylindrical structure 1 having a cylindrical shell construction as the bridge pier of a bridge. In this cushioning part 2, a lower plate 20 and an upper plate 21 are connected together through a main cushioning member 22 between. When a vertical load W which is 50-95% of the buckling load of the cylindrical structure 1 is applied to the cylindrical structure 1 at earthquake, at first only the main cushioning member 22 begins the compressive plastic deformation, and then a sub- cushioning member 23 begins the compressive plastic deformation. Namely, after mean stress acting on the main cushioning member 22 sandwiched with the lower plate 20 and the upper plate 21 is increased and reached to the maximum mean stress, the main cushioning part 22 begins compressive plastic deformation, the mean stress value is gradually decreased in accordance with increase of the compressive plastic deformation quantity, and the main cushioning member 22 is deformed by a fixed quantity of compressive plastic deformation and a fixed clearanceδbetween a supporting plate 24 and the underside of the upper plate 21 is disappeared.
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