This paper focuses on the collapse analysis of a planar RC frame. This research is based on an experimental study presented in the literature. The analyses are conducted using a dedicated software based on the Applied Element Method. This numerical method is able to model accurately all the structural behaviour stages leading up to the collapse itself. A very good match between the experimental and numerical results is observed. The numerical investigation highlights several behaviour stages for the model RC frame. Moreover, the contribution of the RC slab and the impact of the concrete strength on the overall collapse mechanism is discussed and evaluated through numerical investigation.