Study On Seismic Behavior Of Special-Shaped Column Composed Of Concrete-Filled Square Steel Tubes Energy Dissipation Structure

The application of the special-shaped column composed of concrete-filled square steel tube(SCFST)system in high-rise residential buildings in high intensity area is worthy of further study for the effect of lateral resistance performance.Therefore,it is of great significance to study the application of damping technology to the Specialshaped Column Composed of Concrete-filled Square Steel Tube Braced Frame system,which is of great significance to promote the application of the system in high-rise residential buildings in high intensity area.In this paper,the basic theory and structure analysis method of damping control are described in detail.On this basis,the seismic performance of the SCFST column braced frame system in high intensity area is discussed by using the software MIDAS and YJK.Through two kinds of software,the performance indexes of natural vibration period,storey displacement angle and floor shear force are analyzed.The analysis shows that the structure has good seismic performance in the area of 8 degree fortification.According to the interlayer displacement angle,the axial compression ratio and the damage condition,it is suggested that the structure should not be more than 50 m in the area of 8 degree fortification.The distribution law of axial force and lateral load of the special-shaped column composed of concrete-filled square steel tube in each column limb is studied using ABAQUS software,together with the influence of axial compression ratio and transverse load angle on bearing capacity and failure characteristics of SCFST column.The analysis shows that the horizontal load distributes to each column limb of the special-shaped column according to the stiffness in horizontal load direction.Moreover,the column limb at the far end of the acting point in the direction of load is forced to yield ahead of the proximal column limb.The joint plate between the columns effectively conveys the horizontal load,and the connecting plate with the smaller angle between the horizontal load direction bears the larger shear force.The symmetrical axis direction of special-shaped column is the weakest direction of its stiffness,and its bearable horizontal load decreases with the increase of axial compression ratio.In order to study the mechanical behavior of concrete-filled square steel tubular special-shaped columns,an experimental study on the buckling restrained braced frame of concrete-filled square steel tubular composite special-shaped columns was carried out.The test results show that the failure mechanism of the test member is that buckling restrained braces and steel beams appear plastic hinge in turn.What's more,the specialshaped columns did not destroy.The hysteretic curve of the member is full,while the skeleton curve looks like S,and the degradation of strength and stiffness is not obvious.The hysteretic curve of buckling restrained brace is so full that the energy dissipation capacity is strong,which effectively protects the frame structure.In the finite element analysis,the failure mechanism of the component is basically consistent with the test,and the bearing capacity and horizontal displacement of the component are slightly larger than the test results.The comparison of the common braced frame with the special-shaped column shows that the seismic performance of the anti buckling support frame of the special-shaped column is obviously better than that of the common bracing frame with the special-shaped column.On the basis of experiment and finite element analysis,the buckling restrained brace structure of special-shaped column frame is analyzed.The results show that the buckling restrained brace structure of special-shaped columns and the ordinary support structure of special-shaped columns are basically the same under the condition of frequent earthquakes.However,in the case of fortification intensity earthquake and rare earthquake,the buckling restrained brace can effectively absorb seismic energy,provide additional damping,reduce structural deformation,and effectively protect the main structure.