RESEARCH OF SPRING RIGIDITY COEFFICIENT EQUATION FITTING FOR RECTANGULAR STEEL TUBE COLUMN AND CONCRETE

Setting transmission member in concrete-filled rectangular steel tube ( CFRST ) column has solved theproblems that steel tube and concrete is difficult to work together for existing CFRST. The elastic foundation beamtheory was applied to concrete-filled steel tube column of setting transmission component, when solving the coefficientof concrete work by analytical method, vertical spring stiffness of steel tube, rotational spring stiffness of steel tube, vertical spring stiffness of concrete were critical. Their solutions were obtained by the finite element method, whichwas more complicated and non-intuitive for practical engineering applications, moreover, was also a certain difficulty.Defining vertical spring stiffness coefficient of steel tube, rotational spring stiffness coefficient of steel tube and verticalspring stiffness coefficient of concrete, and using the finite element simulation, it was analyzed the various factors ofthree spring stiffness coefficients, and obtained the relationships between all influencing factors and three springstiffness coefficients respectively. Considering the coupling effect between various factors, it was modified the fittingequations and had the total fitting equation, and the error analysis was done. The results showed that the total fittingequation of the three spring stiffness coefficients solved solution of the spring stiffness effectively, and provided areliable basis for the further solution of the concrete work-bearing factor.