TY - JOUR
T1 - Structural Behaviour of Cold-Formed Steel Built-Up Closed Cross-section Columns - Assessing the Influence of Parameters and Design Methods
AU - Selvaraj, Sivaganesh
AU - Madhavan, Mahendrakumar
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/11/1
Y1 - 2023/11/1
N2 - Structural behaviour of cold-formed steel (CFS) built-up closed cross-section columns subjected to local, global, and local–global interactive failure is investigated. The objective is to assess the appropriateness of six different Direct Strength Method (DSM) based designs proposed by various researchers including the current AISI codification. A total of 595 built-up column test results from the existing literature were used for assessment. The comparison of test results and design predictions indicated that the primary influential parameters that inhibit or induce the local–global interaction failure in closed cross-section built-up columns were not well incorporated into the designs. Owing to that, the DSM design predictions are largely scattered; conservative by a maximum of 258% and unconservative by 60%. The reliability analysis was carried out to statistically assess the design methods. It is found that five out of six designs are reliable but do not represent the actual structural behavioral trend. Following this, representative sample results and failure modes were analyzed for identifying the influential parameter that causes design methods to result in inaccurate failure load. The analysis shows that the strength of the column increases with a decrease in intermediate fastener spacing (less than the local buckling halfwave length) due to the flange overlapping effect while the column strength decreases due to local–global interactive buckling caused by a larger intermediate fastener spacing (higher than the local buckling halfwave length). Finally, the paper presents future directions on how the DSM should evolve for the accurate design of built-up closed cross–section columns.
AB - Structural behaviour of cold-formed steel (CFS) built-up closed cross-section columns subjected to local, global, and local–global interactive failure is investigated. The objective is to assess the appropriateness of six different Direct Strength Method (DSM) based designs proposed by various researchers including the current AISI codification. A total of 595 built-up column test results from the existing literature were used for assessment. The comparison of test results and design predictions indicated that the primary influential parameters that inhibit or induce the local–global interaction failure in closed cross-section built-up columns were not well incorporated into the designs. Owing to that, the DSM design predictions are largely scattered; conservative by a maximum of 258% and unconservative by 60%. The reliability analysis was carried out to statistically assess the design methods. It is found that five out of six designs are reliable but do not represent the actual structural behavioral trend. Following this, representative sample results and failure modes were analyzed for identifying the influential parameter that causes design methods to result in inaccurate failure load. The analysis shows that the strength of the column increases with a decrease in intermediate fastener spacing (less than the local buckling halfwave length) due to the flange overlapping effect while the column strength decreases due to local–global interactive buckling caused by a larger intermediate fastener spacing (higher than the local buckling halfwave length). Finally, the paper presents future directions on how the DSM should evolve for the accurate design of built-up closed cross–section columns.
KW - Cold-formed Steel Built-up columns
KW - Design Predictions
KW - Direct Strength Method
KW - Fastener Spacing
KW - Local-global Interactive buckling
UR - http://www.scopus.com/inward/record.url?scp=85167395030&partnerID=8YFLogxK
U2 - 10.1016/j.engstruct.2023.116600
DO - 10.1016/j.engstruct.2023.116600
M3 - Journal article
AN - SCOPUS:85167395030
SN - 0141-0296
VL - 294
JO - Engineering Structures
JF - Engineering Structures
M1 - 116600
ER -