Repair or restoration of a nonconforming structure or a structure on a nonconforming lot. Any nonconforming structure or structure on a nonconforming lot which has been declared unsafe may be strengthened or restored to a safe condition. A nonconforming structure or structure on a nonconforming lot, which has been damaged by fire, storm, explosion, act of God, act of the public enemy or other casualty, may be repaired or reconstructed, provided that repair or reconstruction is finished within a one-year period, and further provided that any structure or building and the lot on which it is situated shall conform to the applicable requirements of this Code in force at the time the damage occurred.