tile countertop

How can I determine if my cabinet bases are strong enough to support ceramic tile coutertop. With the exception of the area where the cooktop is located, the cabinets have oak face frames with 1/2 or 3/4 inch plywood sides It is hard to determine since I can see what is under the existing laminate countertop. The cooktop area is not a true cabinet but a face frame attached to 1/2 inch plywood. If the frames are not strong enough is there any way to increase there strength?