| 摘要 |
PROBLEM TO BE SOLVED: To provide a floor joist for a clean room, which is excellent in vibration isolation performance and workability, and to provide a clean room joisted floor using the floor joist. SOLUTION: The floor joist A is formed of a wide-flange beam 1, and concrete 2 filled between upper and lower flanges 1a, 1b of the same. The upper flange 1a has bolt insertion holes 3a formed therein at locations on both sides of a web 1c of the wide-flange beam, while the lower flange 1b has bolt insertion holes 3b formed therein on both the sides of the web 1c, and the holes 3a, 3b are concentric with each other. Further sleeves 4 and nuts 5 are embedded in the concrete between the upper and lower flanges in a manner concentric with the upper and lower bolt insertion holes, respectively. Then the floor joist A is laid on an upper surface of a steel beam 7, and a lower end of each long bolt 8 which is inserted into the upper and lower bolt insertion holes formed in the wide-flange beam and screwed into the nut, is inserted into a through hole 9 formed in an upper flange 7a of the steel beam, and the floor joist A is rigidly clamped to the upper flange of the steel beam by means of a nut 10 screwed onto a lower-side threaded portion of the long bolt protruded downward from the through hole. Further a base plate 12a of a grating bearing leg 12 is set on an upper surface of the floor joist, and the base plate is rigidly clamped to the floor joist A by a nut 13 screwed onto an upper-side threaded portion of the long bolt 8 protruded upward from a through hole formed in the base plate. In this manner the clean room joisted floor B is constructed. COPYRIGHT: (C)2006,JPO&NCIPI
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