Pedro D. Simão

Guidance for the Design of Spliced Columns

Steel columns in sway and nonsway frames that are spliced along their length generally have a lower strength capacity in compression. This load capacity can be further reduced owing to the inevitable presence of small geometrical imperfections in the form of the out-of-straightness of the column and column segment misalignment. The current work examines the buckling behavior of a framed spliced column with initial imperfections and the possibility of a nonuniform cross section. A geometrically nonlinear model accounting for imperfect elastic buckling behavior is formulated using the differential equations of equilibrium. This is followed by a study of the imperfection sensitivity to the linearly evaluated critical load. A discussion on the variation of the load-carrying capacity with the level of imperfections on a practical spliced column is also presented. The findings suggest that a spliced column can be considered equivalent to a prismatic Euler column, with an appropriate effective length, for design purposes. In this context, some implications for design are deduced from the presented analysis.