Axial Compression Than The Experimental Study And Theoretical Analysis Of The Impact Of The Seismic Performance Of Composite Frame

In order to compensate the shortcomings of traditional structures,and fully play the properties of various materials,composite structure is gradually applied to the construction and bridge engineering. Since the structure is a new type of structure,its seismic capacity has been tested in the earthquake,but the resarch of its seismic capacity in the world is not yet ripe now,therefore,the seismic capacity research of composite structure such as concrete-filled steel tubular-composite frame structure has far reaching significance.This paper do experimental study and theoretical analysis to concrete-filled steel tubular-composite frame structure,mainly study the influence of axial load ratio to the seismic capacity of frame structures.The sepcific study are as follows:Firstly,a low-cyclic test of three frames concrete-filled steel tubular column-steel concrete composite frame has been done under different axial, the hysteresis loop and skeleton curve of framework under different axial were obtained,the seismic capacity such as ductility, stiffness degradation, strength degradation, energy dissipation under different axial were analyzed.This paper mainly research on the seismic capacity influence of different axial to composite frame.Secondly,this paper conduct nonlinear finite element analysis to composite frame structure, a finite element model of composite frame was established by using the finite element analysis software ansys.With concrete that suitable for the mechanical characteristics of concrete filled steel tube and steel constitutive framework,the entire load-displacement process of composite frame were analyzed and test results were compared with the experiment reselts,and the influence of concrete strength, steel yield strength and steel ratio to the mechanical properties of composite frame were analyzed.Thirdly,from the condition that seismic must meet certain ductility,this paper analyzes axial load ratio limits problem of composite frame,and ductility coefficient of concrete filled steel tube columns under different axial was calculated,and then by deducing the relationship between the theory and design axial load ratio,obtain the design axial load ratio under different seismic level.