PURPOSE: To make it possible to install a receiving plate easily and to prevent an installation damage as well in the case when a bearing is loaded on and installed to the receiving plate.

CONSTITUTION: A substantially cross-shaped projection 5a is formed on the bottom of a rack 3 of an unit 4 and the bottom 5d is machine-finished flatly. On one hand, a receiving plate 10 is mounted to a pier 2 at a reference height H and then positioned and installed. This construction makes it possible to install easily a bearing 5 to the receiving plate 12 and transfer a load to the receiving plate 10 uniformly by way of the bearing 5 and protect a receiving material 10a from damages by means of a projected part 5a. It also increases a space between the receiving plate 10 and a winding pipe 7. It is, therefore, possible to place concrete easily in the case when the receiving plate 10 is installed.