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<p>Structural duplex stainless steel (DSS) is being increasingly used in non-aesthetic and even non- visible structural elements in bridges to reduce the cost of in-service maintenance compared to use of carbon steel. Until recently, use of stainless steel in the built environment has been driven by architects seeking to develop aesthetically satisfying structures. There is now an emerging trend towards utilising the high corrosion resistance of DSS to reduce total life cycle costs. To validate the assumption that structural DSS are a durable solution, an in-service inspection of DSS in selected European bridges has been undertaken. This assessment has concluded that recently introduced EN 1993-1-4 Annex A 2015 is an appropriate selection tool for structural applications, although in some cases it was found to be somewhat conservative. Having confirmed DSS as a durable material, a case study of the use of DSS in the Söderström bridges in Stockholm is presented. To reduce life cycle costs, this project makes extensive non-visible use of a new DSS grade, EN 1.4662.</p>

<p>Duplex stainless steel (DSS) usage in bridge construction has increased significantly in the last twenty years because of the material’s exceptional mechanical properties, good corrosion resistance, negligible need of maintenance and thereby low life cycle costs. Three suitable DSS grades used in bridge structures are EN 1.4462, 1.4362 and 1.4162. It is important to choose a DSS grade which is appropriate for the intended service environment, not least because the price of the material generally increases with the corrosion resistance. This work presents the results from various bridge inspections where DSS has been used for the main structure in environments which were retrospectively classified in accordance with EN 1993-1-4 Annex A. The results illustrate successful application of DSS structures and could also be used to provide data for future design standard revision, for example EN 1993-1-4, Annex A, relating to material selection.</p>