Pounding of seismically designed low-rise reinforced concrete frames

Substantial damage to buildings from seismic pounding is the result of earthquakes in many urban areas. This study investigated the effects of pounding in low-rise buildings, which had been individually designed for seismic resistance, using a three-dimensional numerical model. The pounding between the heavier and lighter buildings was conducted for four cases with floor to floor collision and zero separation gap; the total heights of the buildings were varied. The ratio of the storey mass between the heavier to the lighter buildings in all cases was 1.7. The results demonstrated that the heavier buildings were almost unaffected by the collision, and that seismic design without consideration of pounding is acceptable. However, the pounding had more influence on lighter buildings. A significant increase of inter-storey drift and the storey shear force was found. At the top floor of the lighter building, the inter-storey drift and the storey shear force were increased in the range of 35-73% and 20-46%, respectively, compared with no-pounding events. In addition, severe damage at beam-column joints was found. Hence, lighter buildings require special attention during a seismic pounding event.