| This research investigates new analysis methods for study of the behavior of two- and three-dimensional steel and composite steel-concrete building structures under monotonic and cyclic loads. An analysis model is developed and implemented to study the cyclic, full nonlinear behavior of frames composed of steel columns, partially-restrained steel-concrete composite girders and partially-restrained composite connections. The model directly considers the contributions of the slab and each of the connection components to the force transfer at the beam-to-column joints. Flexibility-based and mixed beam and beam-column elements are developed for full nonlinear analysis. These elements are capable of capturing distributed plasticity effects with high accuracy. Comparable displacement-based beam-column elements are also developed, and the relative performance and advantages of the different elements are investigated. Both two- and three-dimensional beam-column element formulations are addressed. The kinematics of deformation of the three-dimensional beam-column elements includes finite rotation, warping of the cross-section due to torsion, flexural-torsional coupling and the Wagner effect. The research extends an object-oriented finite element programming framework and the developed elements are implemented within this framework. Various constitutive models, nonlinear solution procedures, and simulation capabilities are implemented and supported within the framework. |
