Ductility, strength and stability of concrete-filled fabricated steel box columns for tall buildings

This paper is concerned with the ductility, strength and stability behaviour of concrete filled steel box columns. A cross-sectional analysis procedure which considers the nonlinear material properties of steel and concrete has been developed. The steel behaviour includes the presence of residual strains and stresses. A parametric study is undertaken to monitor the influence of residual stresses, concrete strength and steel strength on the thrust-moment-curvature response. A parameter known as the ductility ratio is calculated and this gives an indication of the ability of a structural member to deform. From the results of the thrust-moment-curvature response, strength interaction diagrams are also developed. Slender column behaviour for these structural members is described and methods by which to determine the strength are discussed. A design example is presented which shows the use of both the strength interaction diagrams and the slender column buckling procedure developed by other researchers. Further research areas are then outlined and discussed in order to elucidate the behaviour and design of these highly efficient column members in tall buildings. (C) 1998 John Wiley & Sons, Ltd.