The capacity of rectangular hollow section (RHS) and Square hollow section (SHS) coldformed stub columns with two opposing central circular openings at column mid-height were
experimentally studied in this research. The selected stub columns had a minimum yield strength
of 357 MPa. The impact of two opposing central circular openings on the structural performance
of tubular steel stub columns was examined for perforation size to flat-width ratios of 0.4 and 0.6.
Also, these columns with openings were strengthened with a doubler plate.
This study presents the ultimate column abilities, load-end shortening curves, regional
geometric faults, and typical failure modes extracted from the current test program. Further, this
thesis has presented a study of the potential of strengthening the RHS and SHS stub columns by
using external doubler plates with two distinct heights with doubling and tripling the perforation
diameter.
This thesis also presents a numerical analysis that was carried out using the software
ABAQUS to simulate test results and conduct a parametric study. Finite element (FE) models
were initially developed and validated against previous test results. Following validation, FE
models were created to generate ultimate column capacities for a variety of cross-sections and
perforation sizes to flat wide ratios ranging from 0.2 to 0.8. A total of 417 stub column capacities
comprising 21 test and 396 FE analysis results were employed to assess the potential of
strengthening the RHS and SHS stub columns by using external doubler plates with two distinct
heights with doubling and tripling the perforation diameter.
Further, the ultimate compression column abilities, load-end shortening curves, and typical
failure modes were extracted from the current numerical analysis. Also, the results were compared
to the nominal axial capacity member in compression provided in Section E of North American
Specification AISI S100-16 (2016). As for the cold-formed thin-walled perforated (RHS) and
(SHS) steel stub column strengthened with external doubler plates, the ultimate buckling load
capacity is increased by about 40%, especially for perforation ratios ranging from 0.4 to 0.6. |
