Review of design codes of concrete encased steel short columns under axial compression

Abstract EN

In recent years, the use of encased steel concrete columns has been increased significantly in medium-rise or high-rise buildings.

The aim of the present investigation is to assess experimentally the current methods and codes for evaluating the ultimate load behavior of concrete encased steel short columns.

The current state of design provisions for composite columns from the Egyptian codes ECP203-2007 and ECP-SC-LRFD-2012, as well as, American Institute of Steel Construction, AISC-LRFD-2010, American Concrete Institute, ACI-318-2008, and British Standard BS-5400-5 was reviewed.

The axial capacity portion of both the encased steel section and the concrete section was also studied according to the previously mentioned codes.

Ten encased steel concrete columns have been investigated experimentally to study the effect of concrete confinement and different types of encased steel sections.

The measured axial capacity of the tested ten composite columns was compared with the values calculated by the above mentioned codes.

It is concluded that non-negligible discrepancies exist between codes and the experimental results as the confinement effect was not considered in predicting both the strength and ductility of concrete.

The confining effect was obviously influenced by the shape of the encased steel section.

The tube-shaped steel section leads to better confinement than the SIB section.

Among the used codes, the ECPSC- LRFD-2012 led to the most conservative results