# A Parametric Computational Study of RC Building Structures under Corner-Column Removal Situations
## 5 Conclusions  
The work carried out included a wide parametric study conducted by advanced FE models validated by a purpose-built full-scale RC building structure subjected to a sudden corner-column removal scenario. The parameters included (i) tensile concrete strength (f\({}_{\text{ct}}\)), (ii) flexural reinforcement ratio (\(\rho\)), (iii) number of floors (nf), (iv) column removal time (cnt) and (v) the applied superimposed load (q). The influence of each parameter was studied on deflections, drifts, forces, damage, Alternative Load Paths (ALPs) and Dynamic Amplification and Load Increase Factors (DAFs and LIFs), for both displacements (DAF\({}_{\text{LD}}\), LIF\({}_{\text{LD}}\)) and loads (DAF\({}_{\text{LF}}\), LIF\({}_{\text{LF}}\)). From the results obtained, the following conclusions can be drawn:  
* The tensile concrete strength has a strong influence on the numerical predictions of displacements and structural damage. This affects the computed DAF\({}_{\text{LD}}\), with low values of f\({}_{\text{ct}}\) generally giving more realistic values of DAF\({}_{\text{LD}}\). This parameter did not have a significant effect on the reactions/forces. * The same conclusions can be drawn for the influence of the flexural reinforcement ratio, although in this case it also had a significant influence on the member reaction/force values. However, this influence is not transferred to the computed DAF\({}_{\text{LF}}\), which is not significantly influenced by this parameter. * The number of floors also has a clear influence on both vertical displacements and member reaction/forces. However, DAF\({}_{\text{LD}}\) and DAF\({}_{\text{LF}}\) are not influenced by this parameter. * Column removal time has a strong influence on vertical displacements and bending moments, although it barely affects the reaction forces' peak and residual force values. Due to the wide variation found, it is always recommended to assume the worst possible case at the limit of the GSA recommendations [36] to establish a column removal time equal to a tenth of the structure's fundamental period without the missing column (T/10). * The applied superimposed load had a strong influence on all the aspects studied. A comparison was made between a load combination for ULS and a common design accidental load. Results showed that considering a more aggressive scenario than a design accidental situation could result in making different and erroneous recommendations on the safe side, in some cases (e.g., excessive deflections or forces can be considered in a design accidental situation but this is a persistent and transient situation), but these recommendations would still be unsafe for the DAF\({}_{\text{LF}}\) (i.e., resulting in a lower value than in a design accidental situation). * The test and FE models in this paper showed that Vierendeel action was the main ALP of the structure for the particular case investigated, i.e., without infill walls and subjected to a design compliant corner-column removal situation. The rest of the column above the removed one acts as a key element in effectively activating this ALP. However, for this ALP to be safe, a series of reinforcement details should be in the design phase of the structure. Conceptualization, J.M.A., J.S. and M.B. ; methodology, J.M.A., J.S., M.B., E.B. and J.G.-R.; software, E.B., M.B. and J.G.-R.; validation, E.B. and M.B. ; formal analysis, M.B. and E.B. ; investigation, J.M.A., J.S., M.B., E.B. and J.G.-R.; resources, J.M.A. and J.S. ; data curation, E.B. and M.B. ; writing--original draft preparation, M.B. and E.B. ; writing--review and editing, J.M.A., J.S., M.B., E.B. and J.G.-R.; visualization, E.B. and M.B. ; supervision, J.S. and J.M.A. ; project administration, J.M.A. and J.S. ; funding acquisition, J.M.A., J.S., M.B. and E.B. All authors have read and agreed to the published version of the manuscript.