Research On Seismic Performance Of RC Frames Considering SSI Effects And Infill Wall Stiffness Interaction

The Soil-structure interaction and the stiffness effect of infilled walls are important factors that affect the seismic response of structures.In general,the rigid foundation assumption is usually applied to the engineering design process without considering the influence of irregular arangement of infilled walls.However,in the actual earthquake damage,the rigid foundation assumption and the irregular arrangement of the infilled walls may cause structures to form weak layers.Therefore,the seismic performance of the reinforced concrete frame structure is studied through the "weak layer" position which is caused by the irregular layout of the filled wall and the SSI effect in the paper,and the IDA method is used to evaluate its anti-collapse ability,and the main work is completed as follows:(1)The RC frame structure with infilled walls generally has the sensitive area of "weak layer".When the "weak layer" is in the sensitive area of “weak layer”,the response of the structure on the maximum inter-layer drift under the action of rare earthquake has obvious adverse effect,the maximum interlayer drift angle increases by 1.020~1.614,while the weak layer is located outside the sensitive area of the weak layer,the influence of the irregular layout of the infilled walls on the maximum inter-layer drift can be ignored.(2)For the RC frame structure with filled walls and the bottom air frame,considering the influence of the stiffness effect of SSI and filled wall s,the deformation of the structure mainly concerntrates on the bottom layers of the structure so that the energy dissipation capacity of the frame structure is obviously weakened,that is similar to the effect of the weak layer.Therefore,it is suggested that the designers should consider the adverse effect of SSI and the stiffness of infilled walls in calculating the elastic plastic deformation of the structure when the elastic and plastic deformation of the structure is checked.At the same time,the stiffness ratio of the layers must be further restricted in a smaller range.(3)when the ground motion intensity Sa(T1,5%)is between 0~0.2g,the 50% division IDA curve under the near field pulse earthquake is very close to the result of the ordinary far field earthquake,and the near field pulse effect does not have great influence on the structure when the structure has not entered the strong nonlinear stage.When the ground motion intensity Sa(T1,5%)exceeds 0.2g,the 50% division IDA curve of the structure under the near field pulse earthquake is more rapidly entering the strong nonlinear phase than that under the ordinary far field earthquake,and its inter-layer drift response increases rapidly with the increase of the ground motion intensity,the near field pulse effect is remarkable.Compared with the far-field seismic effect,the near-field pulse effect reduces the average collapsed peak acceleration of the structure to about 0.2g.