Evaluation of Near-Field Earthquake-Induced Pounding in Building with Friction Pendulum Bearing Considering Seismic Gap of 360 Standard

In this paper, the effect of seismic pounding of adjacent structures on buildings isolated by double (DFPB) and triple friction pendulum bearings (TFPB) is investigated. The seismic gaps between buildings are calculated based on the Instruction for Seismic Rehabilitation of Existing Buildings, standard No. 360 of Iran, which is not considered for friction pendulum bearings in the previous studies. To this end, a three-dimensional single-story building model is created in the MATHLAB program considering two scenarios including the case without pounding and the case with it. In addition, fifteen different TFPBs and six DFPBs are utilized as seismic isolators to cover a wide range of fundamental periods of the isolation system. Finally, nonlinear time history analyses with seven pairs of ground motion records are conducted to obtain some of the seismic responses of buildings including base shear, drift, story acceleration and maximum displacement of the isolation system. The results show that the seismic pounding considerably increases responses of base-isolated buildings. For example, the floor acceleration and the drift ratio of isolated building with TFPB increased 2 and 6 fold because of seismic pounding. It shows that the seismic gaps calculated by the formula of standard No. 360 may not be sufficient to prevent severe seismic poundings and increase of seismic responses.