Steel Buildings in Europe

Part 4: Detailed Design of Portal Frames 4 - 41 8.3.3 Stability under uplift combinations When the frame is subject to uplift, the column moment will reverse. The bending moments will generally be significantly smaller than those under gravity loading combinations, and the column will remain elastic. Out-of-plane checks should be undertaken in accordance with Expression 6.62 (See Section 6.2 of this document). 8.4 In-plane stability In addition to the out-of-plane checks described in Section 8.3, in-plane checks must be satisfied using Expression 6.61. For the in-plane checks, the axial resistance M1 y Ed   N is based on the system length of the column. The buckling resistance M1 y,Rk LT   M should be taken as the least resistance from any of the zones described in Section 8.3. 8.5 Design summary  Columns should be IPE or similar sections with Class 1 or Class 2 proportions under combined moment and axial load.  The section should ideally be able to resist the high shears within the depth of the eaves connection, without shear stiffening.  Critical cross-sections should be checked to Section 6 of EN 1993-1-1.  Detailed stability checks, as defined in Sections 8.3 and 8.4 must be carried out to ensure adequate stability.