Study On Seismic Behavior Of Novel Steel-concrete Mixed Structure

Thanks to advantages of both steel structure and concrete structure, steel frameconcrete core-tube hybrid structure has been widely used in China. However, it hasadverse distribution of shear, because of huge difference of rigidity and mechanicalproperty of frame and core-tube. And ductility of its connection is poor. The bucklingrestrained brace semi-rigid connection steel frame and concrete core-tube mixed structurehas been put forward. Ductilityofconnections ofthe novel steel-concrete mixed structureis good. Buckling restrained brace has excellent energy dissipation capacity. And it iseasy to replace. The frame with buckling restrained brace can strength lateral stiffnessand improve bearing capacity. However, the research on seismic performance of thenovel mixed structure is scarce.Elastic lateral displacement of numerous buckling restrained brace semi-rigidconnection steel frame and concrete core-tube mixed structures were calculated by Ansysand Abaqus. The correctness and reliability of them was verified with each other.Through the elastic-plastic time history analysis, this paper analyzed seismicbehavior of steel frame and concrete core-tube structure, semi-rigid connection steelframe and concrete core-tube structure and novel mixed structure by comparinginter-story drift, energy dissipation and failure model of the three kinds of structure.Research shows that: novel mixed structure has better capacity to reduce inter-story drift,absorb and dissipate energy.Two kinds of finite element model of buckling restrained brace semi-rigidconnection steel frame and concrete core-tube mixed structures were constructed:(1) withsame elastic lateralstiffness and different stiffness ratios ofthe frame, brace and coretube, (2) with different layouts of buckling restrained braces. Through the elastic-plastic timehistory analysis under action of rare earthquake, the influence of stiffness ratios of theframe, brace and core tube, height of building and layouts of buckling restrained braceson deformation, distribution of shear and failure model were studied. And suggestionsfor design were made in two aspects:(1) the stiffness ratio which leads to smallerinter-story drifts and a better failure model,(2) the layout of buckling restrained braceswhich leads to smaller inter-story drifts and well-distributed stiffness.