Economics/ |
Stainless Steel
Reinforcing Bars (Rebar) Numerous countries are experiencing problems created by a decaying reinforced concrete infrastructure. This often necessitates the costly repair or replacement of important structures - some of them after only a relatively short lifetime. Faced with these problems, governing authorities are increasingly demanding a greater emphasis on life cycle costs for new construction projects, as opposed to considering only the initial capital costs. This approach helps to focus attention on total costs, including the frequency and cost of future maintenance and replacement work. In the USA, the National Highway System (NHS) Designation Act came into effect in November 1995. It requires every NHS project over $25 million to be subject to a life cycle cost analysis. Cost analyses for concrete highway bridges have revealed that the selective use of stainless rebar increases the initial capital project costs by 1% to 15%, depending on the size and complexity of the bridge. This "modest" initial cost increase can be offset by reduced maintenance costs, as illustrated by the following example:
Adapted from: S.R. Kilworth and J. Fallon "Stainless Steels for Reinforcement", 2nd Regional Conference on Concrete Durability in the Arabian Gulf, Bahrain Society of Engineers, 1995. In the above example, the initial capital cost increase amounts to 4% for Type 304 and 8% for Type 316. If "disruption costs" are added to maintenance costs, the argument in favor of stainless steels becomes even more compelling. In the case of repairs to strategic bridges or elevated highways these indirect costs include lost productivity, wasted fuel, delays in deliveries etc. These costs may be difficult to estimate but can be very high for major highways. In the case of toll bridges/tunnels or harbour facilities, the loss of productivity and revenue can be determined more easily. The above negative effects can be summed up with a recent statement by a North American political leader: "Roads are arteries of our economic prosperity; clogged arteries are bad for your economic health."
The following potential advantages can be cited for stainless steel rebar:
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