How does galvanic corrosion primarily affect steel bridge components?

Galvanic corrosion primarily affects steel bridge components through an electrochemical process that occurs when two dissimilar metals are electrically connected in the presence of an electrolyte, such as water containing salts. The more active metal (the anode) corrodes at an accelerated rate, while the less active metal (the cathode) corrodes at a slower rate or not at all. In steel bridges, galvanic corrosion can occur when steel is in contact with another metal, like aluminum or copper, particularly in areas exposed to moisture and de-icing salts. The steel acts as the anode and corrodes preferentially, leading to a loss of material and a reduction in the structural capacity of the affected component. This type of corrosion is often localized near the connection point between the two metals and can be significantly more aggressive than uniform corrosion.