An apparatus for supporting an axial load between first and second planes, the apparatus comprising: a first member positioning between the first and second planes and having opposite ends, the first member defining an axial bore therethrough for passage of an anchor bolt, one of the ends bearing the axial load of the first plane, the other end having a first spiraling face; a second member positioning between the first and second planes and having opposite ends, the second member defining an axial bore therethrough for passage of the anchor bolt, one of the ends having a spherical face, the other end having a second spiraling face positioning against the first spiraling face of the first member; and a third member positioning between the first and second planes and having opposite ends, one of the ends bearing the axial load of the second plane, the other end having a spherical face positioning against the spherical face of the second member; wherein the first and second spiraling faces (220, 250) of the first and second members (210, 240) each has a plane which is inclined so as to allow an axial adjustment along a central axis when the first and second members (210, 240) are rotatable relative to one another; characterized in that: the second member has a central portion extending beyond the spiraling face, the central portion being positioned in a central bore of the first member when the spiraling faces (220, 250) of the second and first members (240, 210) are positioned against one another; and a locking fastener threading into a side of the first member and engageable with the central portion of the second member to prevent rotation of the first and second members (210, 240) relative to one another. a first member positioning between the first and second planes and having opposite ends, the first member defining an axial bore therethrough for passage of an anchor bolt, one of the ends bearing the axial load of the first plane, the other end having a first spiraling face; a second member positioning between the first and second planes and having opposite ends, the second member defining an axial bore therethrough for passage of the anchor bolt, one of the ends having a spherical face, the other end having a second spiraling face positioning against the first spiraling face of the first member; and a third member positioning between the first and second planes and having opposite ends, one of the ends bearing the axial load of the second plane, the other end having a spherical face positioning against the spherical face of the second member; wherein the first and second spiraling faces (220, 250) of the first and second members (210, 240) each has a plane which is inclined so as to allow an axial adjustment along a central axis when the first and second members (210, 240) are rotatable relative to one another; characterized in that: the second member has a central portion extending beyond the spiraling face, the central portion being positioned in a central bore of the first member when the spiraling faces (220, 250) of the second and first members (240, 210) are positioned against one another; and a locking fastener threading into a side of the first member and engageable with the central portion of the second member to prevent rotation of the first and second members (210, 240) relative to one another. the second member has a central portion extending beyond the spiraling face, the central portion being positioned in a central bore of the first member when the spiraling faces (220, 250) of the second and first members (240, 210) are positioned against one another; and a locking fastener threading into a side of the first member and engageable with the central portion of the second member to prevent rotation of the first and second members (210, 240) relative to one another.