Accurate assessment of seismic performance of reinforced concrete columns（RC columns）is significant to ensure the safety of reinforced concrete structure subjected to earthquake action. In order to derive a reasonable prediction by Pushover analysis

a calculation method for determining lateral load-deformation curve

unloading rigidity and reloading rigidity of RC columns subjected to combined flexural and shear force is proposed based on test data analysis in the PEER (Pacific Earthquake Engineering Research Center) Structural Performance Database

and the formula for calculating the equivalent damping ratio according to hysteresis loop area is also provided. In this paper

conventional section analysis techniques are employed for modeling the flexural behavior of lateral load-deformation relationship

and the modified formulas with actual data analysis are implemented for modeling the effect of shear and slip of the longitudinal bars at columns end. Unloading rigidity and reloading rigidity of the columns are determined by statistical analysis on relations between themselves and secant rigidity of the columns respectively. Finally

a single-degree of freedom (SDOF) system is taken as an example to illustrate the applications of the proposed model for developing the corresponding “capacity curve” and performing pushover analysis on columns. The influences of primary parameters

such as shear-span ratio

axial load ratio

reinforcement ratio and stirrup ratio

on seismic performance of columns are also analyzed.