galvanized steel
is there any special considerations in using galvanized structural steel with galvanized bolts? do the holes have to be drilled larger to accomodate the galvanized coating? is astm a924 applicable? any other astm's?
oversized holes in galvanized
the galvanized bolt and nut assembly must be sized to accomodate the coating thickness. the overtapping of the nt is done by the manufacturer and there is nothing special to be done by the engineer.
the hole in the connected part is not adjusted. the standard 1/16" oversize is enough to account for the thickness of the galvanizing. increasing the standard hole size will probably end up violating the rcsc bolt code tolerances and increasing the project cost.
see these aisc references:
i spec hand wire brushed for slip critical connections
dik