There are many benefits to weathering steel but the primary functional benefit which is of most use in structures is the ability to resist corrosion, without further treatment or maintenance, for extended periods of time. Of course, the weathering grade comes at a price, so we wanted to see how this higher initial cost stacked up against the benefits in life.
We have conducted a cost comparison exercise in collaboration with external partners, to look at the costs of a structure fabricated from Celsius Weathering Grade Tube in comparison to one fabricated using a [standard Celsius Tube] product and galvanised for long-life. To make this comparison realistic, we investigated the use of Celsius Weathering Grade Tube for railway OLE electrification structures since weathering steel is frequently used to provide long-life structures associated with railway infrastructure.
On day-1 the cost of the two solutions is not much different. The additional cost of the Celsius Weathering Grade Structural Hollow Sections (SHS) is only a small amount less than the cost of galvanising giving a 2% difference in initial capital cost. Many structures are also painted, but for this assessment we have not included this additional cost element.
We wanted to factor in the cost of maintenance for long-life structures, therefore, we used guidance from the UK Rail Safety and Standards Board. Report T633 from the RSSB indicates that the cost of maintaining overhead line equipment (OLE) can be 0.5% of the capital cost per year.
Factoring this in shows that over a 50 year period the difference in cost between the conventional and the Weathering Grade structure rises from 2% at installation to over 27%.
This costing takes no account of the inherent benefits of using a hot-finished hollow section like Celsius. For example, using Celsius in place of a HEB200 section for OLE structures can result in a 15% reduction in steel weight and so an even more significant reduction in overall cost.
A structure based on a galvanised HEB200 section could cost up to 40% more over a 50 year life than an equivalent OLE structure using Celsius Weathering Grade Structural Hollow Sections.
This cost study shows that Celsius Weathering Grade makes sound financial sense where a design calls for extended corrosion protection.
To find out more about this product visit our Celsius® Weathering Grade page where you can find key product features, technical data and brochure downloads.