A survey of the effects of floor level difference on pounding of adjacent concrete buildings in case of earthquake by non-linear dynamic analysis

During earthquake, out of phase vibration of adjacent buildings leads to pounding and it creates critical loading conditions compared to non-pounding vibration. The damaging effect of pounding is increased in adjacent structures if the floor level of two adjacent structures is different. In this case, the floor level of adjacent building colloids with a point in the height of column of adjacent structure and the column tolerates much shear. In this study, to investigate the effect of pounding on seismic performance of reinforced concrete frame structures, three frames of reinforced concrete 4, 5, 6 -story are selected and with the different floor levels between floors of adjacent buildings, their seismic performance is investigated under pounding phenomenon. These frames are designed at first by SAP software and then by putting structural models with different level difference beside each other, they are analyzed by dynamic non-linear time history by OpenSEES software and Elcentro earthquake. Also, the effect of pounding of structures on displacement of roof and base share force is evaluated. The results show that in adjacent buildings with floor level difference and with close initial period, we should consider the local effects of pounding in case of colliding of the floor of a structure to the column of adjacent structure