| 摘要 |
PROBLEM TO BE SOLVED: To rationalize joist installation work in constructing the floor of a clean room. SOLUTION: In this joist unit 10 applied to the floor of the clean room with a ventilating opening part 4, a plurality of joists 11 erected in a lined-up state between beams, and a plurality of connecting members 12 for connecting the joists 11 to each other, are integrally connected in grated shape beforehand. The whole joist unit 10 is made of precast concrete, and the joists 11 and the connecting members 12 are integrally formed. In this case, prestress is applied to the joists 11. The cross-sectional shape of the joist 1 is formed in trapezoidal shape with the upper part smaller in width dimension than the bottom part.
|
