Robust impact design of steel and composite building structures: the alternate load path approach

Vulnerability of structures to progressive collapse and mitigation of the effects of local damages are topics widely discussed. The studies worldwide carried out allowed identifying different design strategies. However, specific knowledge is still limited and this gap is apparent in codes of practice. A European project focusing on robustness of steel and steel and concrete composite structures regarding the effects of impact recently started combining the 2 methods of residual strength and alternate load path. In the framework of the project activities, the Authors aimed their studies on the redundancy of the structure through slab-beam-systems and ductile joint as well as on the local behaviour of the impacted members. For this analytical, numerical and experimental investigations have been planned and executed. The paper describes the experimental activities related to the investigations on the structural redundancy and presents the preliminary test outcomes.