Steel Buildings in Europe

Part 4: Detailed Design of Portal Frames 4 - 22 § 5.6(3) provides additional requirements for non-uniform sections, i.e. the rafters and their haunches. These will automatically be satisfied by the general requirement for uniform sections in the paragraph above where the haunch is formed from a cutting from the rafter section, or cut from a slightly larger rolled section. 5.4 Design summary  Cross-section classification depends on the ratio of moment and axial load.  All critical cross-sections need to be checked for cross-section resistance in accordance with Section 6.2 of EN 1993-1-1.  For plastic design, all sections containing plastic hinges must be Class 1.