Define Inspection of Steel or Cast Iron Substructures?

Corrosion is the principal cause of deterioration in steel waterfront substructures. On bare un-protected steel pilings, corrosion is often most severe just above the high tide line with another zone of severe attack just below the low tide line. The most vulnerable area in rivers is area at waterline where air and moisture cause rust formation. Submerged steel is also subjected to galvanic corrosion.