## 1 Introduction  
Progressive collapse triggered by extreme events is often accompanied by catastrophic losses in terms of human lives and the economy, e.g., as experienced in the 1995 Alfred P. Murrah Federal Building collapse [1, 2, 3, 4, 5]. Therefore, the robust design of structures has gained importance during the last decades [6, 7]. Both in experimental tests [8, 9, 10, 11] and some design codes, e.g., DoD [12], the threat-independent alternative load path (ALP) method is widely used to evaluate the performance of reinforced concrete (RC) building structures against disproportionate or progressive collapse through the notional removal of one or more load-bearing structural members. Considering that tests in this regard are very time-consuming and costly, numerical simulation approaches are usually adopted to study the influences of different parameters on the performance against progressive collapse in detail [6, 13, 14, 15]. Generally, dynamic effects should be considered in the ALP method. A dynamic non-linear time history analysis (NTHA) is currently the most accurate procedure to simulate the sudden column removal scenario [4; 10; 12]. However, the NTHA is computationally cumbersome as both non-linearities and dynamic effects need to be included [3]. Therefore, a static analysis incorporating a dynamic amplification factor (DAF), used to consider the influence of dynamic effects and/or material non-linearity in a simplified way [16], is more often applied, replacing the full dynamic analysis. Alternatively, the energy-based method (EBM) has been developed as an approximate approach to predict the dynamic load-bearing capacity without the need to perform a direct dynamic analysis [17]. The EBM is based on the principle of energy conservation, in which the resistance against progressive collapse is assessed based on the capability of absorbing and dissipating the energy introduced by the unbalanced loads [18; 19]. This approach has proven to be efficient for the analyses following sudden column removal scenarios [20; 21; 22; 23; 24; 25; 26; 27; 28; 29]. [PERSON] et al. [29], for example, compared the results from the EBM to the results of direct dynamic analyses for two 10-storey RC frames subjected to middle column removal scenarios and found a good agreement between both. Similarly, [PERSON] and [PERSON] [17] applied the EBM to approximate the maximum dynamic responses of two steel moment-resisting frames, in which it was found that the EBM results were close to the results of non-linear dynamic time history analyses. The model uncertainty introduced by using the EBM is however not yet well understood and some studies directly apply the EBM without validation against non-linear dynamic analyses. [PERSON] et al. [21], for example, used the EBM to calculate the time-dependent dynamic responses in relation to four aging RC structures subjected to middle column loss scenarios, although the results of the EBM were not compared with any results from direct dynamic analyses. In terms of experimental investigations, to date, only two series of experimental investigations have been reported in the literature (see [PERSON] et al. [23]) that enable to verify the effectiveness of the EBM, in which a 2 \(\times\) 1 bay flat slab structure subjected to a corner column removal or penultimate column removal was investigated. To date, there are insufficient experimental results to allow for a direct quantification of the EBM accuracy from experimental data. Therefore, the EBM accuracy can reasonably only be determined through comparison against non-linear dynamic analyses. Further background to the EBM is presented below in Section 2. Importantly, the exiting studies in relation to the use of the EBM were only applied to the case of a structure subjected to a middle column removal scenario, in which the assumption of a single deformation mode was usually satisfied.