(a) ncrete pads or foundations shall be a minimum of two thousand five hundred (2,500) pounds per square inch (psi). (b) Plastic pads or foundations shall be tested in the lower fifty percent (50%) of each soil class. TABLE A Pier Spacing Table Load Beaning Capacity Footer Size 16” x 16” 18-1/2” x 18-1/2” 20” x 20” 26” x 26”