The web of a H-section column has been completely corroded at the air-moisture interface with the concrete encasement leaving a hole in the web. The proposal is to break out the existing concrete and weld plates onto the web that will bridge over the hole in the web and will be welded on all four sides to good steel.
The plates will be on both sides of the web. If the web is 8 mm what should the thickness of the plates be? At a minimum should they be 4 mm to reinstate the loss of section?