Investigation On Seismic Behavior And Optimal Layout Of Special-shaped Column Frame Structure With BRBs Based On Concrete Damage Constitutive Relation

In order to investigate the enhancement effect of Buckling-Restrained Braces(BRBs)on the seismic performance of special-shaped column frame structure,according to the concrete damage constitutive relation and buckling restrained principle of BRB,there is the research of the BRB,special-shaped column frame and BRB-frame composite structure system in this paper:The BRB with single core plate Q225 LY is simulated by the finite element analysis software to investigate it’s hysteretic behavior.The results show that BRB’s equivalent viscous damping ratio increases continuously before ultimate load,there is no downward trend,and the energy dissipation capacity is good,the BRB can yield effectively without buckling instability.The simulation results are in good agreement with the BRB’s lying test results.Investigate the seismic behavior of special-shaped column frame structure with diagonal BRBs by the pseudo-static test,and make a comparative research with special-shaped column frame structure without BRBs.The result shows that the BRB effectively delays bond-slip phenomenon between rebars and concrete,and weakens the deformation recovery lag phenomenon.The BRB can make the frame be prevented from damaging while producing large lateral deformation and withstand the more load and displacement cycle.At the same time,the energy dissipation mechanism and yield mechanism of special-shaped columns are changed,so that the structure can absorb large load cyclic energy after yielding.The finite numerical simulations are almost consistent with the pseudo-static test results,both of them shows that there isn’t the out of plane instability phenomenon of BRB in the special-shaped column frame structure with diagonal BRBs before reaching the frame’s ultimate load,and the BRB can perform its performance from beginning to ending.According to the damage constitutive relation given in the Code for design of concrete structures GB50010-2010,based on the energy equivalence principle of Sidiroff,the tension and compression damage constitutive relation of concrete which is applied to ABAQUS software is derived.At the same time,introduce the restoring factors of concretetension and compression damage stiffness under cyclic loading,and the finite element dynamic time history analysis of three-dimensional special-shaped column frame is carried out by making use of the tension and compression damage constitutive relation of concrete which is derived above.And investigate the dynamic response of special-shaped column concrete frame structure under the El-centro wave,Taft wave and artificial wave.The BRBs are applied to the three-dimensional special-shaped column frame structure and establish a three-dimensional finite element model of the composite structure to do modal analysis,dynamic time history response analysis and investigate inherent character and dynamic response of the frame structure.Compare the seismic performance enhancement effect of special-shaped column frame with four kinds of BRB’s layout ways which are herringbone,parallel linear,X shape,diamond,and determine the layout arrangement with better seismic performance,in quest of better improving the seismic behavior of special-shaped column frame structure.