Experimental And Theoretical Research On Seismic Performance Of Inorganic Polymer Concrete-filled Steel Tubular Columns

The inorganic polymer round concrete-filled steel structure is a new type ofcomposite structure, which not only has the characteristics of inorganic polymerconcrete, but also has the advantages of concrete-filled steel. The study of mechanicalproperties for this structure is not very mature and the most research concentrates onthe static aspects of basic members currently. In this paper, based on the pseudo-statictest, the experimental study on seismic performance of inorganic polymer concretefilled circular steel tubular column considering the variation of axial load ratio andsteel ratio were carried out. On this basis, the seismic performance analysis,cumulated damage analysis and finite element analysis for the inorganic polymerround concrete-filled steel tubular columns have been done, to lay a solid foundationfor the application of inorganic polymers round concrete-filled steel tubular columnsin practical engineering.1. Experimental study on the basic mechanical properties of inorganic polymerconcrete and steel, the basic parameters of material properties (elastic modulus andstress-strain relation), provides the theoretical basis for the seismic performance ofstructures and finite element analysis. The elastic modules of inorganic polymerconcrete is3.1455×104N/mm2(lower than ordinary concrete).The peak strain ofthe inorganic polymer concrete stress-strain curve is higher than that of ordinaryconcrete and the measured yield strength and ultimate strength of steel are muchhigher than the specification. The results show that the ductility of the inorganicpolymer concrete is better than ordinary concrete.2. Comparative experimental study on the seismic performance of five inorganicpolymer round concrete-filled steel tubular columns that the axial load ratio andsteel ratio are different and one ordinary concrete-filled steel tubular column, showsthat the inorganic polymer round concrete-filled steel tubular columns and ordinaryconcrete-filled steel tubular column under cyclic loads have good seismicperformance. From the performance analysis of the energy dissipation and ductility,the seismic performance of the inorganic polymer round concrete-filled steel tubularcolumn is better than ordinary concrete-filled steel tubular column. The failure modes are basically bending damage. The axial load ratio and steel ratio have aneffect on hysteretic curve, stiffness, energy dissipation capacity and ductility ofinorganic polymer concrete-filled steel tubular column. With increasing the steelratio, the hysteretic curves of inorganic polymer round concrete-filled steel tubularcolumns are plumper; elastic stiffness of skeleton curve, the horizontal ultimatebearing capacity and ultimate displacement increase, the energy dissipation capacityand ductility have also increased. Therefore, though increasing the steel ratio ofcomponents could improve the seismic performance of inorganic polymer roundconcrete-filled steel tubular columns in practical engineering.3. The cumulated damage model of inorganic polymer round concrete-filled steeltubular column was established by using the principle of conservation of energy,analyzing cumulated damage degree of components by the model under cyclicloading. The results show that the damage index when the components damagerange between0.4and0.7, and appropriately increasing axial load ratio and steelratio can reduce the damage degree of components.4. Simulate the force process of the inorganic polymer round concrete-filled steeltubular columns under cyclic loading by the ABAQUS. The results show that thefinal failure pattern obtained from the finite element is consistent with the testresults, bending damage. Overall, the skeleton curve of finite element is goodagreement with the experimental results that basically reflects the changes ofstrength and the ductility of the components in the whole loading process.At last, the main results of this paper are concluded, and put forward theproblems that need to further study and solve.