where SCFAX(p), SCFIPB(p) and SCFOPB(p) are, respectively, the SCFs at
point p for AX, IPB and OPB loads. σn − AX, σn − IPB and σn − OPB are the
corresponding nominal stresses. In this study, the validity of Eq. (4)
is checked by comparing the test result obtained under two load combinations
with the corresponding values predicted by Eq. (4). The two
loading combinations employed are AX = 120 KN, IPB = −3.6 KN
and OPB = 3.6 KN for Specimen I and AX = 80 KN, IPB = −1.2 KN
and OPB = 3.6 KN for Specimen II. The combined HSS distributions
obtained are shown in Figs. 8 and 9, respectively. In Figs. 8 and 9, it
can be seen that the stress distribution obtained by the superposition
method agreed well with the experimental measurements in both
cases and this confirmed that the superposition method can be applied
to the high strength steel built-up box T-joint.