Analysis For Pounding Of Adjacent Low-rise Buildings In A Dense Cluster Subjected To Ground Motions

Closely spaced adjacent buildings pounding with each other under earthquake action,which is one of the main causes of structural damage and even collapse.In the earthquake-prone areas of China,adjacent low-rise buildings in a dense cluster are widely distributed.Damage to tightly packed structures caused by pounding has often occurred in previous earthquakes.However,at present,domestic and foreign scholars mainly study the pounding of two adjacent structures under the action of earthquake,but there are few studies on the collision response of low-rise adjacent buildings with compact layout.This dissertation mainly investigates the pounding mechanism of adjacent low-rise buildings in a dense cluster.A lumped mass single-degree-of-freedom shear model is used to simplify the building.Both linear and nonlinear finite element model was established,in which the nonlinear performance of the structures were characterized by a trilinear force-deformation relationship.Finally,the pounding response law of the structures in seismic excitation during the linear and nonlinear stage is summarized.The main contents include:(1)To analyze the displacement response law and collision force response law of adjacent low-rise buildings in a dense cluster under earthquake action.The results show that the pounding can coordinate the displacement response of the structures in both linear and nonlinear stages.Therefore,the displacement response of the relatively flexible structures are decreased and that of the relatively rigid structures are increased compared with that of the nonpounding structures.The larger the difference of natural vibration period,the more likely the adjacent structures are to collide.(2)Adjusting the spacing of the structures and the magnitude of the peak acceleration of ground motion,the influence of these on the pounding response rule is studied.The results show that smaller the spacing,the stronger the pounding between most structures.The increase of peak acceleration of ground motion does not change the displacement response law of the structures and the structures which are most likely to pound with others.(3)Four different basic structural configurations of adjacent low-rise buildings in a dense cluster were established to study the influence of configurations changing on structural pounding response.The results show that the relatively flexible structures respond more obvious to the change of structure configuration.(4)Contrast to the characteristics of pounding response of structures in different configurations,the interaction between structures in dense buildings is analyzed: The closer the structure is to the boundary,the more serious the damage will be.If the relatively flexible structures are distributed on the outside and the relatively rigid structures are distributed on the middle,all the structures will be less affected by pounding.(5)The pounding between different layer adjacent low-rise buildings in a dense cluster is analyzed by adjusting the number of layers of some structures in the original model.A strong pounding is easily generated at the position of the staggered layer.Under the earthquake excitation,the structure above the pounding position will produce larger lateral displacement due to the pounding.