Engineering Properties of Composite Mega-Columns with Separately Encased Hot Rolled Steel Profiles

This paper presents an experimental study on the behavior of composite mega-columns with separately encased steel profiles. Ten scaled composite columns were designed, including six 1/4-scaled test specimens and four 1/6-scaled test specimens tested under static and quasi-static loads, respectively. The controlling parameter in this research was the eccentricity ratio of the applied loads. Results indicate that within the 15 percent eccentricity ratio, (1) full composite action between concrete and the steel profiles can be realized, even though the steel profiles are not connected with one another; (2) the current AISC-LRFD, Eurocode4, and Chinese code JGJ 138 are able to predict the flexural capacity of this kind of column with sufficient accuracy and a reasonable margin of safety; and (3) the deformation capacities of the specimens meet the minimum requirement specified by the codes. Finally, a simplified design method is provided in this paper. This research is initiated and sponsored by ArcelorMittal.