Research on mitigating progressive collapse of reinforced concrete (RC) flat plate structures has gained growing attentions. Based on alternative path method, extensive experimental studies have been conducted to simulate column loss scenarios. However, limited research has been performed on the progressive collapse of RC flat plate structures triggered by slab-column joint damages due to slab overloading, which is the main cause of many collapse events. Moreover, studies on dynamic responses of flat plate substructures are rather limited owing to the complexity of the experimental design and execution. This paper presents a preliminary experimental test performed on a 1/3-scaled, 2×2-bay flat plate substructure specimen. In this test, no column was removed but an extreme overloading scenario was employed on the slab to trigger damage to slab-column joints, thereby stimulating the dynamic behaviour of the structure. Experimental results show that brittle punching shear failures have led to significant dynamic responses on the substructure specimen, which was observed by a sudden increase of accelerations over the middle region of the slab when the middle slab-column joint was punched through. This preliminary test also demonstrates the feasibility of such an experimental setup and overloading design to replicate the structural dynamic behaviour. The load-displacement relationship and final crack patterns of the specimen are also presented in this paper.