Use of high strength steel tubular columns in structures: economic study

In many structures, the use of high strength steel (HSS), i.e. with an elastic strength higher than 460MPa, offers an economical benefit in comparison with normal steel (NS). The reason relies mainly on the fact that the cost increases slower than the strength. Moreover, structures using HSS are usually lighter than the ones made of NS leading to a reduction of the costs related to the transportation, fabrication and painting. However, as the stiffness of HSS structures is smaller than the one of NS structures, the second-order effects and, consequently, the serviceability requirements considerably limit the advantages of the use of HSS. The interrelation between the advantages and the drawbacks of HSS leads to the complicate question of knowing whether there is an economic interest of using HSS instead of NS for structural members. This question has not yet been adequately considered in the literature.
The present work aims at investigating building frames with steel and/or composite columns (made of circular steel tubes) with the objective of defining the domains where the use of HSS is economically interesting. Two topics will be addressed: (1) to provide a general view of the economic benefit of the use of HSS; (2) to establish the basis for choosing the material (HSS or NS) for framed structures at the pre-design stage.