The ornamental design for a protectiveshield for a support column, as shown and described.
FIG. 1 is a left front perspective view, in reduced scale, of a protective shield for a support column of our design, showing a support column in dashed lines to illustrate the environment and forming no part of the claimed design;
FIG. 2 is a left front perspective view thereof;
FIG. 3 is a front elevation view thereof, the rear elevation view being a mirror image thereof;
FIG. 4 is a right side elevation view thereof, the left side elevation view being a mirror image thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken lines are for illustrative purposes only and form no part of the claimed design.