Inelastic static and dynamic analyses of slender RC columns considering time-dependent deformation of concrete

Abstract

This dissertation presents an analytical model that can simulate the nonlinear behavior of slender reinforced concrete (RC) columns considering the long-term behavior of concrete using a layered section. The ultimate resisting capacities of slender RC columns according to the variation of design variables, such as the compressive strength of concrete, steel ratio, eccentricity, and creep coefficient, are reviewed through nonlinear analyses of the slender RC columns considering the time-dependent behavior of concrete. On the basis of the obtained numerical analysis results, the resisting capacity reduction factor, which represents the reduction rates of the resisting capacity in a long column corresponding to a short column on a P-M interaction diagram, is introduced. The relationships between the resisting capacity reduction factor and design variables are established from regression and used to determine the ultimate resisting capacity of slender RC columns without any rigorous numerical analysis. The ultimate resisting capacities calculated from the regression formula are compared with those obtained from rigorous nonlinear analyses and from the ACI formula with the objective of establishing the relative efficiency of the proposed formula. In addition, in order to effectively analyze the cyclic behavior of RC columns using the layered section approach, a procedure to quantify the bond-slip effect along the reinforcing bar and indirectly implement the effect into the stress-strain relation of the reinforcing steel is introduced. Comparisons between experimental data and analytical results verify that the proposed analytical procedure can effectively simulate the cracking behavior of RC frame members, which are accompanied by stiffness degradation caused by the bond-slip. Based on the proposed analytical procedure, nonlinear dynamic analyses of slender RC columns are conducted with sixty sets of horizontal and vertical earthquake inputs. This approach differs...