Design optimization of steel-concrete composite structures with requirements on progressive collapse resistance

The present work presents a sizing optimization procedure for collapse-resistant composite steel-concrete frames. An evolutionary optimization algorithm is employed to minimize structural cost subject to constraints associated with: (a) Eurocode 4 provisions for safety of composite column-members, (b) Eurocode 3 provisions for safety of steel beam-members, (c) structural system resistance and (d) progressive collapse resistance. In the numerical examples tested, a variety of damage scenarios is considered. These scenarios are realized by artificially removing column-members from the structural system. The results obtained demonstrate the effectiveness of the proposed optimization approach. Of particular importance is the investigation of the variation in the structural cost achieved when collapse resistance constraints are incorporated in the design process. By enforcing the satisfaction of additional design requirements on system resistance and safety against local failure, structural cost is inevitably increased. This increase