Based on the results concluded from this study, the following
interesting findings are offered.
1. The comparisons indicate that the 2005 AISC-LRFD is
more conservative than the 1999 AISC-LRFD. Although
the formulas between these two specifications look quite
different in format, the resulting nominal strengths are
virtually the same and the design strengths differ due to the
different resistance factors assumed (0.75 versus 0.85).
2. The CFT compressive strength equations given in the 1999
AISC-LRFD are also applicable to CFT rectangular columns
with a higher f 0
c limit of 63–84 MPa. The test results reveal
that the 1999 AISC-LRFD design strengths are conservative
and tend to penalize these CFT columns with higher concrete
strength of 63–84 MPa. The 2005 AISC-LRFD is more
receptive with the adoption of a higher f 0
c of 70 MPa. This
revision to the 1999 AISC-LRFD is justifiable based on the
results concluded from this study.
3. The design strength of a CFT column with high-strength
concrete determined by the 2004 EC 4, the 2004 AS-5100
or the 2001 CSA S16-01 is more conservative than that from
the AISC-LRFD (1999, 2005).