Steel Buildings in Europe

Part 4: Detailed Design 4 – 26  Unrestrained for the construction condition and either: - Fully restrained for the in-service condition (floor beams supporting precast planks) - Restrained at points of load application for the in-service condition - Unrestrained for both construction and in-service conditions. Depending on the slenderness of the beams, there may be a substantial difference of resistance between restrained and unrestrained conditions. It follows that, where the restraint condition improves when the structure is fully constructed, separate verifications should be carried out for both construction and in-service stages. The detailed design process is presented in Figure 5.1 to Figure 5.4. It is possible to cover all the cases listed above by appropriate consideration of the restraint conditions and hence the design buckling resistance described in Figure 5.4.