Robustness of steel and composite buildings suffering the dynamic loss of a column

In case a vehicle impacts a building frame, one or several columns may be damaged or even completely destroyed. Nowadays, it is a concern to mitigate the risk of progressive collapse of the whole structure further to such a localised exceptional event. Although this robustness requirement is part of several design codes, very few precise practical guidelines are provided, especially as far as dynamic failures are concerned. The present research focuses on building frames suffering the loss of one internal column. The dynamic response is more specifically investigated, with the aim to understand this behaviour in order to eventually derive simplified procedures for robustness assessment.
This paper first briefly presents the main previous achievements related to the prediction of the static response of a plane frame suffering a column loss. The investigations into the dynamic behaviour are then summarised, which constitutes the core topic of the paper. For sake of simplicity, the dynamic response is described using a basic substructure that was proved to show many similarities in behaviour with a global frame losing a column. A simplified model is finally developed for the prediction of the considered system dynamic response.