ABSTRACT
Reviewed implementations of finite element method (FEM) for analysis of elastic plane bodies and trusses enable us to state basic provisions of FEM for analysis of arbitrary elastic systems – of the frames in that number. The stiffness matrix of a system is constructed from stiffness matrices of its finite elements. Whilst the stiffness method gives exact distributions of internal forces in members (in the case of frames, insofar as the hypotheses of bending are fulfilled), the peculiarity of FEM calculations of systems including planar of spatial bodies is their approximate character. Note, however, that the stiffness method is more exact, because it takes into account the axial strains of members. The models constructed from elastic finite elements (FEs) are used for analysis of reinforced-concrete skeletons of multi-story buildings. At the final stage of analysis, for every FE, the most hazardous combinations of loads are established, which serve as an input for constructing the reinforcement of the skeleton.
