Very often, especially in densely-resided areas and city centers, neighboring buildings are constructed very close to each other, without sufficient clearance between them. Thus, during strong earthquakes, structural poundings may occur between adjacent buildings due to deformations of their stories. Furthermore, in the case of seismically isolated buildings, pounding may occur with the surrounding moat wall due to insufficient seismic gap at the base of the building. The current study presents a simple but efficient methodology that can be used to numerically simulate the incorporation of rubber layers between neighboring structures with relatively narrow seismic gaps in order to act as collision bumpers and mitigate the detrimental effects of earthquake-induced poundings. The efficiency of this potential impact mitigation measure is parametrically investigated considering both cases of conventionally fixed-supported and seismically isolated buildings subjected to various earthquake excitations. The results indicate that under certain circumstances the incorporation of rubber bumpers in an excising seismic gap can reduce the amplifications of the peak responses of the structures due to pounding.