Using Solid Superelements for Nonlinear Analysis of Slab-and-Beam Structures in the PRINS Software

The article presents a methodology for nonlinear static analysis of slab-and-beam structures using finite elements constructed using the three-dimensional theory of elasticity and plasticity. Multilayer plate/shell elements and solid beam elements (superelements) are used to analyze structures made of heterogeneous materials, including reinforced concrete. In most currently used software products, beam finite elements are constructed either on the basis of the classical theory of strength of materials or on the basis of the three-dimensional elasticity theory. When using the three-dimensional theory, restrictions are introduced on the shape and size of cross-sections, and all characteristics are reduced to points lying in the end sections of the beams along their axes. Both of these approaches make it difficult to simultaneously take into account physical and geometric nonlinearity, therefore the development of alternative methods for nonlinear static analysis of structures is relevant. To avoid this drawback, a superelement for modeling reinforced concrete columns and beams as part of combined slab-and-beam systems is proposed in this article. To date, there are no alternatives of the proposed superelement for analyzing reinforced concrete structures in known commercial finite element products. The developed methodology is adapted to the PRINS software. An example of calculating the load-bearing capacity of a two-story frame using this software is given. The PRINS software can be used by engineers of design and scientific organizations to solve engineering problems related to the analysis of reinforced concrete structures.