High‐Strength Steel Columns in Steel Structures – Establishment of Reference Slenderness Ratios to Select the Appropriate Steel Grade

Abstract In the context of structural optimisation, high‐strength steels represent the highest strength‐to‐weight ratio of the existing steels, thereby contributing to the optimisation of steel structures by reaching the same level of resistance with a reduced material quantity and resulting in lighter buildings requiring less extensive and costly foundations. New production technologies are already available for the manufacture of hot‐rolled steel sections with a yield strength up to 500 MPa in Europe and 80 ksi (550 MPa) in the United States, which comply with the product norms for civil engineering applications. The selection of the right steel at the right place may result in further investments by manufacturers in the future to develop the optimal material solution for each application. Nevertheless, the use of mild steels is still often preferred for hot‐rolled sections due to a lack of information regarding the existing high‐performance products and the advantages they offer, as well as a scarcity of availability due to the current low demand. Furthermore, using a higher steel grade is often associated with an increase in the unitary cost of steel, accompanied by an increased carbon factor, a reduced weldability and ductility as well as an increased risk of local and global buckling instabilities. This paper demonstrates the considerable weight, cost and carbon savings that can be attained through the selection of an appropriate steel grade for multi‐storey building columns and propose reference slenderness ratios to facilitate the selection of the steel grade.