The best protection is preventative. Make sure that artwork proposals take into account landscaping needs well before a commission is completed. If a sculpture is surrounded by grass, then be sure that its base is protected from potential damage by weed whacking or mowing—this may mean placing it on a concrete pad, protecting it with rubber mulch (or a similar substance), or speaking to your maintenance professionals about proper precautions when working near the artwork.
If the artwork is already installed, then it may be necessary to add a “mow strip” or buffer that ensures space between the artwork and grass.