Seismic Behavior And Vulnerability Analysis Of Concrete Filled Square Steel Tube Frame-Steel Plate Shear Wall Core Tube Structure

Concrete filled steel tubular frame-steel plate shear wall core tube structure has been applied in high-rise buildings.The frame part of the structure gives full play to the advantages of two kinds of materials and improves the strength of the frame.Compared with reinforced concrete shear wall,it greatly reduces the cross-section size of the wall,reduces the weight,and is easy to repair and replace.In recent years,scholars at home and abroad have studied the seismic performance and vulnerability of reinforced concrete frame-shear wall structure,but the research on the concrete filled square steel tubular frame-steel plate shear wall core tube is less.Most of the research focuses on the seismic performance of planar frames.The research on the seismic performance of this type of multi-span frame and high-rise structure is still insufficient.In this context,the seismic performance of this type of multi-span multi-storey structure and high-rise structure is studied,and the seismic performance of the structure under earthquake and the probability of failure at different performance levels are studied.The main contents in this paper are:(1)The low cycle cyclic loading test of a 1:3 scale three-story concrete-filled square steel tubular frame coupled steel plate shear wall is carried out.The failure characteristics and hysteretic curves of the structure are obtained.By using the finite element analysis software SAP2000,the whole structure model based on the pull rod model is established for pushover analysis.The results show that in the whole test process,the plastic development of each component of the test piece is relatively sufficient,and the test piece is finally damaged due to the formation of plastic hinge on the column base,so the structure has better bearing capacity and energy consumption capacity.The pull rod model can better simulate the mechanical behavior of steel plate shear wall.The plastic hinge appears on the coupling beam,steel plate wall and frame beam in turn,which is consistent with the test phenomenon.(2)According to the test geometry,a typical 15 story steel tube concrete frame steel plate shear wall core tube structure is designed according to the relevant specifications.The structural modal analysis,static elastoplastic analysis and dynamic elastoplastic analysis are carried out.The vibration mode distribution,structural performance point,load displacement relationship and the response of the structure under different seismic wave strength are obtained.The results show that the typical structure design is reasonable,the steel plate shear wall can bear large shear,the structure has good bearing capacity,and has strong resistance to deformation under rare earthquake.The yield strength,the width thickness ratio,the floor thickness of the steel plate shear wall and steel ratio are changed to study the performance of the structure under different parameters.The results show that the plastic development of steel plate shear wall with low yield point is sufficient,and steel plate shear wall with high yield point will lead to the failure of frame beam in advance,which is not conducive to the yield energy consumption of steel plate wall.The steel plate shear wall with low height thickness ratio has high bearing capacity,but the plastic development of the steel plate wall is not enough,so it is necessary to select the appropriate height thickness ratio in practical use.The thicker floor can improve the rigidity of the structure,reduce the lateral displacement of the structure,reduce the shear of the core tube in the upper part of the structure,and increase the shear of the core tube in the lower part.The ultimate horizontal bearing capacity of the structure can be significantly improved by increasing the steel ratio of the section.(3)Taking the peak ground acceleration(PGA)as the seismic intensity parameter,11 seismic records were selected according to the site conditions.Taking the maximum inter story displacement angle of the structure as the damage index,the incremental dynamic analysis(IDA)of a typical concrete-filled square steel tube frame steel plate shear wall core tube structure is carried out,and the development process of the plastic hinge of the structure is observed,and the IDA curve cluster of the structure is obtained.Based on the results of incremental dynamic analysis,the vulnerability curve of the structure is obtained.The results show that the sequence of plastic hinge is coupling beam,steel plate shear wall,frame beam and frame column.The plastic hinge of the component is fully developed and the development process is reasonable.Based on the results of vulnerability calculation,the failure probability of the structure under different limit states is obtained.The probability of exceeding the serviceability limit state of the structure is 7.67%under 8 degree frequent earthquake.Under the action of 8 degree basic earthquake,the probability of the structure exceeding the serviceable state after repair is 6.43%,and 0.02%of the probability reaches the state of life safety.The probability of surpassing and approaching collapse is only 0.64%under 8 degree rare earthquake,which shows that the structure has good seismic performance.