Progressive collapse analysis of RC frame building based on Pseudo-Dynamic (PsD) testing with sub-structuring

Accidental loading coming from either natural or anthropic hazards can have serious consequences on civil engineering structures capacity and can lead to progressive collapse (PC). In the case of frame buildings, PC is a subject of interest to assess the residual risk of exposure to death for people inside. PC analysis on large structures is rather performed from a numerical point of view. Experimental tests are often expensive and complicate to setup (dynamic response, removal of the load-bearing element, size of the experiment, etc.). In this paper, the use of Pseudo-Dynamic (PsD) testing combined with sub-structuring technique is proposed. It allows to account for the dynamic response of the entire structure by only testing (quasi-statically) the critical part of the building. In order to demonstrate the applicability of the method to PC, a classic central column removal scenario is considered and applied on a Reinforced Concrete (RC) structure. The latter is a two-bay and three story frame building. The bending response of the RC beam directly connected to the removed load-bearing member is investigated. Only this part (the RC beam) is experimentally tested while the rest of the structure is simulated by finite element analysis within a dynamic framework. The quasi-static response of the beam is measured and interacts with the integration scheme (α Operator Splitting type) to calculate, inter alias, the inertial forces contributions and the displacement fields within both numerical and experimental domains. To validate the approach, a finite element model based on multifiber beam theory is used. The results comparison underlines a very good agreement between both PsD tests and numerical simulations in all configurations considered, in particular the ability of the PsD approach to account for inertial effects within the structural response. It demonstrates the interest to use such a method within the context of PC analysis. More specifically, the method could prove particularly effective to assess Dynamic Amplification Factors (DAF), used for structural design by accounting for PC potential effect (at least within American guidelines).