| Lip-inclined Z-section purlins with unequal flange width can be nested together to form a continuous multi-span beam to reduce the deflection, and increase its load-carrying capacity of loading. But the current specification GB50018-2002 does not consider the effect of lip inclination, hence, it cannot be effectively used in designing inclined lipped Z-section purlins. The primary objective of this study is to analyze the buckling mode of inclined lipped purlins and predict distortional buckling strengths, as compared to the consequence calculated by ANSYS.This study analyses distortional buckling of cold-formed lipped channel section beams and lipped Z-purlins in terms of Hancock model, and calculates distortional buckling strengths and local buckling coefficients of flange using finite element method. Through the comparison of the two consequence, a suggestion is given for the buckling coefficients of lipped channel beams. Then the effects on distortional buckling coefficient due to the angel of lipped flange was investigated, the value of buckling coefficients of inclined lipped flange relative to the angle of the lipped flange is presented.Based on the results of the study, the angle of the lip stiffener has great effects on the buckling coefficients of inclined lipped flange, and cannot be neglected in calculating buckling strengths of inclined lipped Z-section purlins. Comparison showed that, the provisions about the buckling coefficients in the GB50018-2002 Specification are too conservative, the buckling strength of typical section Z200 is only 78% of the results obtained by ANSYS, while the results are close to each other by 1986 AISI Specification and ANSYS. |
