Développement d'essais pseudo-dynamiques sous-structurés pour la caractérisation de la perte de portance appliqués aux ouvrages poteaux-poutres

Due to the current socio-economic context, progressive collapse is of growing interest, as better understanding the phenomenon is necessary to reduce the associated risks. Numerous tests are done in academic research. Experimentally, studies are limited due to cost and setup complexity: a large part of these tests are done quasi-statically on sub-assemblies. The entire structure’s dynamic behavior is generally modeled numerically. However, the level of confidence in the models is very dependent on the selected constitutive laws and parameters. Furthermore, the importance of accounting for the overall dynamic behavior of structures is highlighted by both current state of the art on academic research and by up to date design guidelines. Thus, the sub-structured pseudo-dynamic testing method (used in earthquake engineering) is hereby adapted to the investigation of progressive collapse scenarios. Based on the framework of finite element analysis, the inertial and viscous forces’ contributions are computed. The restoring forces are measured on the structure, which is quasi-statically deformed experimentally. The sub-structuring technique enables to associate to the physically tested part of the structure a larger numerical model. This way, the experimental setup focuses on the critical part of the structure, while the overall dynamic behavior of the structure is still reproduced. The method is adapted to a 2D, reinforced concrete frame. The lower floor’s beams are physically tested, while the rest of the frame is numerically modeled using nonlinear multifiber beam finite elements. A mixed implicit-explicit approach on the time scheme guarantees the numerical domain’s proper convergence, without compromising experimental measurements. Results are presented and discussed, as the method allows to obtain additional information regarding the structure’s response when compared to conventional pushover tests.