Experimental Study On The Seismic Behavior Of The Shear Wall With Concrete-filled Steel Tubular Frames,Column Form Of Reinforcement And Diagonal Bars

In order to research and develop a more superior and efficient anti-seismic component of high-rise building structures,a new shear wall with concrete-filled steel tubular frames,column form of reinforcement and diagonal bars was put forward.The new shear wall was mainly composed of concrete-filled steel tubular frames at both ends,internal column form of reinforcement,and diagonal bars added on the outer side.To further study the seismic working mechanism of the new composite shear wall,three different types of shear wall specimens(the three specimens respectively are ordinary shear wall specimen,ordinary shear wall specimen with concrete-filled steel tubular frames,and the shear wall specimen with concrete-filled steel tubular frames,column form of reinforcement and diagonal bars)were designed and constructed in this paper.The three shear wall specimens were experimented by low-cycle loading,and finite-element analysis were performed.1.The study of low-cycle loadingAccording to the experimental results,the indexes of seismic performance such as failure process and characteristics,bearing capacity,ductility,the process of stiffness degradation and hysteretic behavior of specimens are analyzed.And the damage analysis of specimens are carried out.The results show that: compared with other specimens,the capacity of energy dissipation and bearing capacity of the shear wall specimen with concrete-filled steel tubular frames,column form of reinforcement and diagonal bars are significantly improved,and the stiffness degradation is slower.The ductility and the post-deformation ability is better.Under the condition of the same loading or displacement,the new composite shear wall specimen has has less damage value and lower damaged degree.After analysis,it can be concluded that the concrete-filled steel tubular frames of the new composite shear wall provide a constraint on the wall.The structural form of the column-reinforcement could significantly improve the ductility and the energy dissipation capacity of the new composite shear wall;The diagonal steel bars could effectively increase the stiffness of the new composite shear wall specimen and limit the development of cracks.The concrete-filled steel tubular frames,the column form of reinforcement and the diagonal steel bars could form a good cooperative working mechanism.The organic combination of these structural measures makes the overall seismic performance of the new combined shear wall significantly enhanced.2.The finite-element analysisThrough the ABAQUS finite-element software,the model of shear wall specimen with concrete-filled steel tubular frames,column form of reinforcement and diagonal bars is established and its finite-element analysis is carried out.The analysis results of the finite-element calculation are compared with the experimental results,and the compared results are basically consistent,which indicates that the model of the new composite shear wall established by the finite-element is reasonable and correct.And then,the effects of the thickness of steel tube,strength grade of concrete,axial compression ratio and other factors on the seismic behavior of the shear wall specimens are studied.The results show that the method of increasing the wall thickness of steel tubular has a significant effect on the bearing capacity of shear wall specimens;The method of improving concrete strength to enhance the seismic performance of shear wall specimens is generally cost-effective;the method of increasing the ratio of column-reinforcement and the ratio of diagonal bars has a certain impact on the improvement of the bearing capacity of shear wall specimens.