BASE-ISOLATION STRUCTURE FOR CONSTRUCTION

PROBLEM TO BE SOLVED: To provide a base-isolation structure for a bridge, capable of improving base isolation effects by achieving a longer natural period for the upper construction part of a construction while preventing the occurrence of resonance.SOLUTION: The base-isolation structure includes a plurality of bridge columns 2 (bridge abutments 1) installed at spaces from one another, a plurality of bridge girders 3 supported by the bridge columns 2 and installed at spaces from one another, base-isolation devices 10 provided between the bridge column 2 and the bridge girder 3, and connection dampers 4 connecting the adjacent bridge girders 3 to each other. The base-isolation devices 10 each include a spherical slider having a convex surface, and a spherical supporting part joined to the bridge girder 3 and the bridge column 2 for sandwiching the spherical slider, and having a concave surface opposed to the convex surface for slidably supporting the spherical slider on the concave surface. They are friction pendulum type base-isolation supports which can change natural periods for the bridge girders 3 by means of the curvature of the concave surfaces, where the natural period for at least one of the plurality of bridge girders 3 is different from those for others.