Design of cold-formed HSS channels for bending and eccentric compression: Bending in the plane of symmetry

Open channel sections manufactured from high strength steels (HSS) were tested. The sections were bent in the plane of symmetry of the cross-sections. The roll-formed test profiles, one double-U, two C and two hat profiles with yield stress of 560-670 N/mm² and material thickness of 4-6 mm were taken from normal production. In spite of relatively thick cross sections the buckling of plates or edge stiffeners was observed in some profiles. Tests were made for bending, eccentric compression and concentrated load. Bending tests of short and long beams (16 tests) were made to determine the cross-sectional properties and lateral buckling resistances of the beams respectively. The eccentric compression tests with two different lengths (18 tests) studied the interaction between compression and bending resistance. Concentrated load tests (9 tests) examined the interaction between web crippling and bending moment. The test results together with other tests results from literature are compared with the design resistances determined according to the proposed design method. This simplified method is a combination of the Eurode 3/Annex A and AISI 1989 codes. The method is satisfactory for normal design, but in some cases it was found to be too conservative. For instance, the reduction of stiffener thickness in the case of stiffener buckling seems to reduce the cross-sectional area to too great a degree, and in the case of eccentric compression, when the eccentricity lies on the shear centre side of the cross section, the capacity is underestimated. Comparisons with the other test results confirmed that the accuracy of the design rules do not depend on the yield strength or wall thickness.