Patent ID: 7231318

Claim:
A method comprising: measuring or obtaining TOW, an annual wetness time (h) in a location; measuring or obtaining W, an annual mean wind speed (m/sec.) in the location; measuring or obtaining C, an airborne salt amount (mdd) in the location; measuring or obtaining S, a sulfur oxide amount (mdd) in the location; measuring or obtaining T, an annual mean temperature (K) in the location; determining a corrosivity index Z of an atmospheric corrosion resistant steel at the location where the atmospheric corrosion resistant steel is to be used; determining a corrosion amount of the atmospheric corrosion resistant steel using the corrosivity index Z; and selecting a steel type for a steel structure, or designing or maintaining the steel structure based on the determined corrosion amount, wherein the corrosivity index Z is determined using the following equation Z = α · TOW · exp ⁡ ( - κ · W ) · C + δ · S 1 + ɛ · C · S · exp ⁡ ( - E a R · T ) where Ea is activation energy (J/mol) of a corrosion reaction of the atmospheric corrosion resistant steel, R is a gas constant (J/K(K·mol)), α is a coefficient constant, and κ, δ, and ε are influence degree constants.