[en] In 1969, a catastrophic event occurred in UK at the Ronal Point residential building where the progressive collapse of the building, initiated by a localized gas explosion, was observed. Further to this event, some codes and standards, and in particular the British Standards, impose to the designer to ensure the structural integrity of building in order to avoid the progressive collapse of the latter further to an exceptional action.
In fact, the progressive collapse of a building is the result of a change in the structural system and of the load path associated to the loss of one or more main structural members. In other words, the existing load path is suddenly modified and the loads supported by the building are reported to the foundation through an alternative load path. Accordingly, the remaining structural members are overloaded by additional loads; the latter have to be able to support these loads and to possess a sufficient ductility.
In the last decade, researches on this topic were initiated at the Argenco Department of Liège University. The present paper reflects part of these activities; in particular, some investigations dedicated to the investigation of the behaviour of a frame further to a column loss are presented. In another article presented by J.F Demonceau, H.N.N. Luu and J.P Jaspart within the present conference is devoted to the investigation of the behaviour of the frame when significant membranar forces developed within the structure. In particular, in this paper, a simplified substructure which is able to simulate the behaviour of a structure further to a column loss is defined. The present paper presents the analytical methods requested to define the parameters influencing the response of the simplified substructure.