PURPOSE: To facilitate construction work by joining a diaphragm at the lower end of a column to the upper end face of a joining pipe on a sill fixed to the anchor bolt of a foundation through bolts.

CONSTITUTION: A sill 15 composed of a horizontal base plate 16 and a short joining pipe 17 vertically stuck to the upper face of the base plate 16 is fixed to an anchor bolt 22. An annular groove 4 on the lower face of a diaphragm 3 at the lower end of a column 1 is installed on the sill 15, and the tip of a bolt 25 is threadedly thrust in a tapped hole 18 for fixing the diaphragm 3. In addition, a pouring in port 19 is openedly provided on the side of the joining pipe 17, and a joint pipe 26 is protrusively provided from the pouring in port 19 for pouring in concrete. Thus since the diaphragm is joined to the joining pipe on the sill, their transport can be facilitated.