| 摘要 |
<p>PURPOSE:To reduce the constructing period and cost of a duct-equipped floor structure by making a duct device to be easily and accurately set to a prescribed level without placing concrete twice on a supporting plate made of plywood, etc., used for forms. CONSTITUTION:Concrete is placed on a supporting plate 2 until the level of the concrete nearly reaches the same level as of the upper end section of a duct main body 8 while the main body 8 is maintained at a prescribed level above the plate 2 by means of a height adjusting mechanism A which can adjust the height of the main body 8 and variation in the level caused by the bending of the plate 2 when the concrete is placed is corrected by means of the mechanism A. At the same time, the upper surface of the placed concrete is finished so that the upper surface can nearly become the same height as that of the upper end section of the main body 8.</p> |
