Numerical Analysis on Nonlinear Creep Effect of Reinforced Concrete Beams

Abstract

In order to numerically analyze the influence of nonlinear creep effect on the long-term deflection of reinforced concrete beams under different stress levels, this paper considers the strength attenuation caused by concrete damage in the Miguel nonlinear creep model, and introduces the evolution parameters of concrete compressive damage by using the strain equivalent hypothesis. Combined with the Chinese design specification, the value of damage evolution parameter is determined, and a new nonlinear creep model is established. ANSYS UPFs was used for secondary development, and the nonlinear creep model subroutine and the linear creep model subroutine of Chinese design specification were compiled. The mid-span deflection variation of reinforced concrete beams under long-term load was obtained by finite element calculation. The results show that when the compressive stress of concrete is less than 0.4 times of the axial compressive strength of concrete, the calculation results of the nonlinear creep model established in this paper are consistent with those of the linear creep model in the design specification. When the compressive stress of concrete is 0.4 ~ 0.7 times of the axial compressive strength of concrete, the nonlinear creep model established in this paper has better prediction capability than the linear creep model in the design specification.