| 摘要 |
PROBLEM TO BE SOLVED: To provide an earthquake-resistant fixed offshore type caisson pier bridge in which the need for a foundation work such as excavation of ground is obviated and the construction cost is low and further, influence of an earthquake on bridge girders can be effectively reduced. SOLUTION: In this earthquake-resistant fixed offshore type caisson pier bridge, the weight of bridge girder 2 is supported by a plurality of caisson piers 1 which are provided with a specified buoyancy and whose bottom 1d is fixed to the bottom of the sea or the bottom ground of a river. The internal structure of the caisson pier 1 is formed to have an antimotion water tank structure. When an earthquake occurs in the ground g1, a relative slide arises between the bottom 1d of the caisson pier 1 and the surface of a mound to generate a vibration isolation action. Thereby, the earthquake force is attenuated and the influence on the upper structure such as the bridge girders 2 or the like is reduced. When a large wave or tidal current acts thereon, the caisson pier 1 and the bridge girder 2 swing but in this time, the water in the antimotion water tank (ballast tank) of the caisson pier 1 swings to generate a stabilizing action. Hence, the motion of the caisson pier 1 and the bridge girders 2 is attenuated.
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