Analysis Of Influence Of Floor And Infill Wall On Seismic Performance Of RC Frame Structure

The slab and infill wall play an important role in the seismic response of the reinforced concrete frame structure,and the frame structure with the infill wall using the cast-in-place plate is also the most common form of building structure.In the traditional related seismic design,the slab and infill wall did not bear the horizontal load caused by the earthquake.However,several earthquake disasters that have occurred in recent years have shown that the joint work of the slab and the infill wall has a certain impact on the seismic performance of the overall structure.especially in the Wenchuan earthquake disaster,many structures did not fully reflect the seismic thinking of the "strong column weak beam" yield mechanism.In order to study the seismic performance and the change of the yield mechanism of the frame structure under the action of the slab and the infill wall,combined with the previous research,the main work of this paper is as follows:(1)Through the research on the reinforced floor wall at home and abroad,in this paper,the influence of cast-in-situ slab on the frame structure is analyzed in depth.The concrete of the floor slab strengthens the compressive strength of the compression zone of the beam frame by means of effective flanges,and the cast-in-place steel bar further enhances the tensile strength of the negative moment zone.Based on the study of the failure mechanism of the infill wall,an equivalent diagonal model for simulating the infill wall is proposed.(2)The reinforced concrete frame structure with a 6-story cast-in-situ slab-filled wall is taken as the research background,and the sap2000 finite element software is used to reasonably model various components.In order to ensure the actual working condition of the slab in the state of three-dimensional frame structure,the complete shell(membrane plus plate)is used to analyze and model the cast-in-situ slab,and the masonry infill wall in the frame structure is simulated by the equivalent slanting bar model.By setting different analytical models,the pure bar frame is compared with the related models with slab and infill wall to explore the difference of related data,and then the impact route of slab and infill wall on the seismic performance of the whole structure under earthquake action is studied.(3)In the case of maintaining other factors of the established model,such as quality,building area,etc.,the "pure rod structure,floor + rod structure,infill wall + rod structure,floor + infill wall + rod structure" are sequentially established,then obtain the vibration mode decomposition response spectrum analysis under multiple earthquakes and analyze the time history analysis under rare earthquakes.The analysis structure shows that the slab and the infill wall can provide certain anti-side stiffness to the structure under the action of the single layer,which reduces the lateral displacement of the structure in the earthquake and plays a good seismic effect.The simultaneous arrangement of the slab and the infill wall provides a large improvement in the overall rigidity of the structure,and the anti-side shifting effect is better.(4)Pushover analysis was performed on the framework structure models established above.Throughout the plastic analysis and the plastic hinge distribution and development model,it can be found that the synergy between the slab and the infill wall has a double-sided effect on the seismic resistance of the structure.On the one hand,plastic sills are suppressed in the initial development due to the significant lateral stiffness increase of the slab and the infill wall.On the one hand,plastic sills are suppressed in the initial development due to the significant lateral stiffness increase of the slab and the infill wall.However,when the plastic hinge develops to the middle stage,especially the infill wall model with cast-in-place plate,the obvious "column hinge" failure mechanism is produced,which violates the seismic concept of the strong column weak beam.This situation poses a certain threat to the design of structural ductile damage.On this basis,this paper compares the reinforcement schemes for the poor yielding mechanism,especially the column hinge failure under the large space at the bottom,and selects the optimal improvement scheme.