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

Open channel sections manufactured from high-strength steel (HSS) were tested. The sections were bent about the axis of symmetry of the cross sections. The roll formed test profiles, one U, two C and one hat cross section with yield stresses of 565 - 655 N/mm2 and material thicknesses of 4 6 mm were taken from normal production. Also one point symmetric Z profile of lower grade steel was included in the test series. Tests were made for bending and eccentric compression. Bending tests for short and long beams (12 tests) were made to determine the cross sectional properties and lateral buckling resistance of the beams respectively. The eccentric compression tests (12 tests) studied the interaction between compression and bending resistance. The test results together with other test results from literature are compared with the design resistance determined according to the proposed design method. The simplified method is a combination of the Eurocode 3/Annex A and AISI 1989 codes. The elastic buckling stresses are calculated using the full, unreduced dimensions, while actual section strength is determined with the effective dimensions. The method is satisfactory for normal design, although in some cases it is found to be too conservative. Comparison with the other test results confirmed that the accuracy of the design rules do not depend on the yield strength or wall thickness. Some non linear FEM analyses indicated the feasibility also in this loading case.