This paper describes an experimental study on the response
of hollow and filled steel members to monotonic and cyclic axial loading.
Monotonic tests were first performed on short specimens to establish their
compressive and tensile axial resistances and to investigate the effect of
infill on local buckling and ductility. These were followed by cyclic tests on
longer bracing members with three different cross-section sizes. The presence
of concrete infill was observed to influence the mode of failure displayed by
the specimens, as well as their compression and tension load responses. The
ductility capacities of the individual specimens are compared, and the effects
of slenderness, steel strength and infill are quantified. The experimental
findings are compared with the recommendations of a number of international
codes of practice and previous research studies on the seismic response of
steel braces. It is found that the infill contributes to the compression
resistance of the brace, even after multiple inelastic load reversals, and that
it can improve ductility capacity by preventing or limiting local buckling.