Strength analysis of reinforced concrete columns with arbitrary cross-section under bieccentric loading

A numerical method to analyze the failure load of reinforced concrete colum ns under bieccentric loading is presented. This method takes into account b oth material nonlinearity and geometric nonlinearity. The nonlinear constit utive relationships of concrete and steel bars are simulated by some cubic- splines. The derived element stiffness matrices are simple addition of the small-displacement stiffness matrix, geometric stiffness matrix and interac tion component matrix. The element model may be used to analyze the ultimat e load according to the material strength or stable limits. The formulation s of reinforced concrete column elements derived here may also be used for beams or columns with arbitrary cross-section. The standard finite element approach presented in this paper is compatible with other finite element mo dels. The theoretical results agree well with the experimental data.