We've ordered some automated gates, and the drawings show concrete pads 400mm BGL which the gate post steelwork then screws down into.    Is there a rule of thumb as to the size these pads should be and/or if they should incorporate any rebar or mesh?   The gate supplier doesn't specify any of this, and groundwokers has just suggested 600mm deep 1x1m pads with no steel or even mesh.   Do I need a strucutral design for these, or are there some general rules which can be followed?