Global Buckling of Castellated and Cellular Steel Beams and Columns
Delphine Sonck Ghent University Belgium
Cellular and castellated members are usually made by performing thermal cutting and welding opera-tions on hot-rolled I-section members. The global buckling behavior of these members will be quali-tatively similar to that of I-section members. Howev-er, it is expected that the buckling resistance will be influenced by the different geometry and the modi-fication of the residual stress pattern during the production of the cellular and castellated members. Current design guidelines for the global buckling of these members are conflicting or lacking altogether and do not take into account the effect of the modi-fied residual stresses, which could possibly be very unsafe. Therefore, the lateral-torsional buckling and weak-axis flexural buckling behavior of castel-lated and cellular members were investigated in a recent PhD investigation at Ghent University.
A series of residual stress measurements demonstrat-ed the increase of the compressive residual stresses in the flanges during the production of these members, which is detrimental for the global buckling re-sistance. This was taken into account in the proposed modified residual stress pattern. The numerical model in which this residual stress pattern was introduced, was validated using the results of a series of lateral-torsional buckling experiments. Based on the results of the numerical parametric study of the global buckling behavior, a first design rule proposal was made. This proposal is similar to the currently used European guidelines for I-section members without openings, but with a different calculation of the cross-sectional properties and a modified buckling curve selection. The PhD dissertation can be downloaded from http://hdl.handle.net/1854/LU-4256332.