Stainless steel is gaining increasing use in structural engineering applications due to its
corrosion resistance, low maintenance costs, high recyclability, aesthetic appeal, excellent
fire resistance and favourable structural properties. The stress-strain behaviour of stainless
steels differs fundamentally from that of carbon steel: stainless steel has a more rounded
response with no clear yield point and significant strain hardening. This has a profound effect
on the structural behaviour of stainless steel elements. The aim of this work is to investigate
the behaviour of stainless steel I-sections under concentrated transverse loading and to
develop design rules that reflect the particular characteristics of the material. Concentrated
transverse loading is a load case where a force acts perpendicular to the flange of a girder
over a relatively small area, causing local failure of the web beneath the load and flange
bending. The current design code for structural stainless steel elements, namely Eurocode 3:
Part 1.4, adopts the same design expressions for stainless steel as for carbon steel for such
loading conditions. A comprehensive experimental and numerical investigation has therefore
been conducted to evaluate the existing provisions and propose new design rules. A total of
34 member tests and over 500 finite element simulations have been performed covering three
types of concentrated transverse loading – internal one-flange, internal two-flange and end
one-flange loading, three stainless steel grades – austenitic, duplex and ferritic and a range of
the key influential parameters. The results showed that the existing design recommendations
are conservative and that there is considerable scope for the development of more economical
design guidance. The new design equations offer 10% - 20% improvements in capacity
predictions over the current design formulae. An alternative design approach, based on
numerically generated reference loads, namely the elastic buckling and plastic collapse load
under concentrated loading, in conjunction with strength curves, has also been proposed. This
required the development of a consistent method for the numerical determination of plastic
collapse loads, which is known to be challenging for the complex failure modes associated
with localised loading. The reliability of both proposed design approaches have been verified
by means of statistical analyses in accordance with EN 1990.