The ornamental design for a sandal with archsupport, as shown and described.
FIG. 1 is a first perspective view of a sandal with arch support showing my new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof;
FIG. 9 is a perspective view of the sandal with arch support thereof; and,
FIG. 10 is a perspective view of the sandal with arch support thereof with the sandal upper removed from the sole to clearly disclose the arch support of the sandal.