Abstract: An upper floor member 30 unitarily includes a floor panel portion 30a for forming a floor surface 12, a first wall portion 30b extending downwards from circumferential edges of the floor panel portion 30a and continuous in the circumferential direction, and a second wall portion 30c spanned between opposed portions of the first wall portion 30b and progressively increased in thickness toward the center of the floor panel portion 30a. The floor panel portion 30a is polygonal in shape, and the first wall portion 30b is progressively increased in thickness toward the center of each side. The first wall portion 30b extends downwards to the vicinity of the lower floor, and its lower end is supported by a support means 18. Thus, a double floor structure which is inexpensive, has a high stiffness, good workability, and offers a high vibration-damping performance can be provided.

Abstract: An upper floor member 30 is unitarily comprised of a floor panel portion 30a for forming a floor surface 12, a first wall portion 30b extending downwards from circumferential edges of the floor panel portion 30a and continuous in the circumferential direction, and a second wall portion 30c spanned between opposed portions of the first wall portion 30b and progressively increased in thickness toward the center of the floor panel portion 30a. The floor panel portion 30a is polygonal in shape, and the first wall portion 30b is progressively increased in thickness toward the center of each side. The first wall portion 30b extends downwards to the vicinity of the lower floor, and its lower end is supported by a support means 18. Thus, a double floor structure which is inexpensive, has a high stiffness, good workability, and offers a high vibration-damping performance can be provided.

Abstract: A hydrostatic anti-vibration system includes a main tank provided on a construction to be suppressed from vibrating and having a main tank body of substantially flat rectangular configuration. Hollow vertical extensions extend upwardly from peripheral edge portions of the main tank body and are filled with a working liquid at a predetermined level with upper air chambers maintained thereabove. Ducts communicate the upper air chambers of the hollow vertical extensions. Intermediate tank portions are disposed at the intermediate portions of respective ducts and contain a vibration suppressing liquid. A pivotal plate is disposed in each of the intermediate tank portions to separate the interior space of the intermediate tank portion into a pair of chambers respectively connected to corresponding portions of the duct. The plate pivots in response to flow pressure of the vibration suppressing liquid. A damping mechanism provides a resistance against displacement of the pivotal plate.

Abstract: A vibration isolating device is provided with an isolator formed by an elastic member of laminated rubber and interposed between the base of a building and its foundation, for supporting the vertical load of the building and obtaining a long period dumping. A main dumper is disposed side by side with the isolator, for effectively damping relatively strong vibrations, and a sub-damper is disposed side by side with the isolator, for effectively dumping relatively weak vibrations. The vibration isolating device damps weak vibrations by the sub-damper and strong vibrations by the main damper, and hence gets effective damping of a wide range of vibrations from slight traffic vibrations to great earthquake shocks.