The cost of galvanized reinforcing steel
The overall cost in using galvanized reinforcing steel in concrete construction depends largely on the extent to which it is used throughout the structure.
For example, it is rarely necessary for the structural core or internal elements of a high rise building or the deeply embedded components of large abutments and foundations to be galvanized. In these situations, it may only be necessary to use galvanized reinforcing steel in surface exposed elements or where foundations may be affected by aggressive or fluctuating groundwater.
In building construction, it is generally found that the cost of galvanizing increases the overall cost of concrete as placed by about 6–10% depending on the size and type of reinforcing steel used, the galvanizing price and the quantity of steel per cubic metre of concrete. On average, the cost of the reinforcing steel would not be more than about 25% of the total cost of the concrete as placed. Considering that the cost of the structural frame and skin of a building normally represents only about 25–30% of total building costs, the additional cost of galvanizing reduces to between 1.5–3.0% of total building costs. This premium reduces to as little as 0.5–1.0% if galvanizing is restricted to surface panels only. However, when taken against the total project cost or final selling price, the added cost of galvanizing becomes very small indeed, often not more than 0.1–0.2%.
An analysis in 2017 by Professor Richard Weyers, Virginia Tech University, examined the diffusion of chloride into concrete decks and its effects on service life in Virginia, USA for epoxy-coated reinforcing steel, batch galvanized reinforcing steel, and 316LN stainless steel reinforcing steel. The total present cost and life-cycle cost figures show that galvanized reinforcing steel provides the most cost-effective protection for reinforced bridge decks with a 100-year life.
When the costs and consequences of corrosion damage to a reinforced concrete building are analysed, this extra cost of galvanizing is a very small investment for superior long-term corrosion protection.
Example of HDG reinforcement used in the construction of sewer pipes to prolong life and resist the effects of corrosion