Compared to the state-of-art analysis and design techniques for buildings and bridges, the methods for large deformation analysis of guyed towers are underdeveloped. Since advanced analysis-based design methods are a significant innovation in the design of 3D steel frames, the extension of this method can considerably simplify the analysis & design procedures for guyed towers. In this study, computational tools are developed for the static nonlinear analysis of guyed masts with fully nonlinear cables. Initially, a flexibility based incremental-iterative procedure was developed without any restrictions on the sag-span ratio. The buckling, post-buckling, and lateral nonlinear responses of the mast and the slackening and post-slackening behavior of cables were studied. The ongoing part of the study involves developing a 3D Total Lagrangian beam element for the static analysis of steel frames. A new kinematic description is being enabled for 3D rotations. The developed beam element is assessed based on the developed analytical model and other problems in the literature. This model can be used for advanced analysis of frames where torsion and flexural-torsional buckling are predominant, and can help extend the well-established Direct Analysis Method (DAM) for frame design to guyed masts. Then, a set of benchmark problems are proposed for use by a designer to assess the capabilities of a computational tool intended to use for DAM.