Nonlinear analysis of in-filled steel-concrete composite columns

A semianalytical method to predict the behavior of in-filled columns is presented in this paper. Moment-curvature-thrust relationships are generated for column cross sections by an iterative process. Nonlinear equilibrium equations resulting from geometric and material nonlinearities are solved by an incremental-iterative numerical scheme based on the generalized displacement control method. Square, rectangular, and circular cross sections of compact steel tubes filled with concrete are considered in the analysis. The columns are pin-ended and subjected to uniaxial or biaxial loading. The accuracy of the proposed analytical method is established by comparing the results with the corresponding experimental values.