GBT-Based distortional buckling formulae for thin-walled rack-section columns and beams

General distortional buckling formulae for both fixed-ended and pinned-ended C-section columns

“…Observing the results displayed in Table 5, we can see that the proposed estimates always compare quite favorably with the values yielded by the Silvestre and Camotim [22][23][24] formulae. However, for some columns, the proposed formulae provide much better (i.e., safer and more conservative) distortional critical stresses than those obtained from the Silvestre and Camotim [22][23][24] formulae because the maximum value of the ratio σ cr,D / σ cr,Dex was 1.079 for the proposed formulae while it was 1.107 for the Silvestre and Camotim [22][23][24] formulae.…”

“…Because Silvestre and Camotim [22][23][24] formulae require a computer program (e.g., a FORTRAN code) to compute the distortional critical stress, only six C-sections were selected from Silvestre and Camotim [22][23][24]. Table 5 shows the critical distortional buckling stress obtained through (1) GBT analyses, the Silvestre and Camotim [22][23][24] formulae, and (2) the proposed formulae for E ¼200 GPa and ν¼ 0.3 with the critical distortional stress ratios σ cr,D /σ cr,Dex .…”

“…Another set of formulae, developed by Silvestre and Camotim [22][23][24], is also compared with the proposed formulae. Because Silvestre and Camotim [22][23][24] formulae require a computer program (e.g., a FORTRAN code) to compute the distortional critical stress, only six C-sections were selected from Silvestre and Camotim [22][23][24].…”

“…However, a sharp corners model, as shown in Fig. 4, was used to analyze distortional buckling by Lau and Hancock [15], Schafer [16,17] and Silvestre and Camotim [22][23][24] for simplified analysis because the corners have only a modest influence on the distortional buckling solutions [27,28]. Additionally, as stated in [29], the influence of rounded corners on the cross-sectional resistance may be neglected if the external radius r r6t (for an internal radius r5t).…”

“…Fortunately, a set of GBT-based analytical formulae to estimate the distortional critical stress in cold-formed steel C-and Z-section members have been derived by Silvestre and Camotim [22,23]. These formulae are applicable to members displaying four end support conditions, and the accuracy and range of validity for the derived distortional buckling formulae was validated in a companion paper [24].…”