Inelastic behaviour of composite members under combined bending and axial loading

This paper presents an account of the results of a series of tests on partially-encased composite steel/concrete beam–columns. The experimental inelastic behaviour of members is examined under idealised conditions representing extreme lateral loading in combination with co-existing axial gravity loads. Members with three different cross-sectional sizes, utilising Grade S460 steel, were employed in the tests. The specimens were tested under major- or minor-axis bending in conjunction with a constant level of axial loading. The experimental arrangement and test rig constructed for this purpose are described together with the material properties and details of the specimens. The main experimental results from tests carried out on ten composite models are presented and discussed. In addition to providing essential data for validating future analytical and design studies, the experimental results and observations enable a direct assessment of several important factors. Particular emphasis is placed on key parameters related to yield and ultimate capacity as well as on ductility and residual strength considerations.