Steel Buildings in Europe

Part 4: Detailed Design 4 – 19 3.4.2 Design for 3 <  cr < 10 More generally, it is appropriate to design the horizontal bracing structure for strength. It is then necessary to take appropriate account of second order effects in accordance with § 2.4.2(2) of EN 1993-1-1. The steps described in Section 2.5 should be followed. 3.5 Design Summary References are to EN 1990-1-1 [5] .  Use the least favourable of Equations 6.10a and 6.10b (where allowed by the National Annex) for the combination of actions for the ultimate limit state.  Use Equations 6.14b, 6.15b, 6.16b for combinations of actions for the serviceability limit state, noting any recommendations in the National Annex.  Use § 6.2.1(2) and (4) to determine the permissible reductions in variable actions applied to large areas.  Carry out the analysis in accordance with Section 3.3 of this publication for gravity loads and 3.4 to assess the significance of second order effects and allow for them if necessary.