A member model that was divided into sub-elements along the member axis and had fibers at these ends, was developed for the combined non-linear analysis. The fibers have the stress-strain relationship of a developed Ramberg-Osgood model. To assume appropriate stiffness, a modified trial method was used. Moreover, large analytical increment for an overall frame was set for the application to a frame with many members. Overall analytical results for a simple truss agreed well with experimental results. In this analysis, one lattice showed so complicated behavior that contained a little first buckling, unloading, and final buckling in another mode.
