This system enables the user to design combined structural elements (RC pylon, precast RC wall panel, RC wall-beam, RC pier, RC lintel) without modifications to the existing analysis procedures in LIRA-SAPR. All of the above-mentioned types of structures are often represented in the design model with a set of plate FEs. This is due to the fact that almost all software that are used to generate an architectural/physical model work with objects such as wall/wall panel/plate. Selected approximation method is quite adequate to consider behaviour of such an element within the framework, but it is not always possible to consider all peculiar features of the strength analysis. For example, the dense mesh for triangulation is required to evaluate stresses because the stresses computed in the gravity centre of FE are used in analysis. One of the most common errors is the simulation of bending and eccentrically-compressed/tensioned elements with one FE along the section height.
To design combined structural elements, the bar analogues (bar elements similar to them, with identical sections and materials) are created for such elements. Bar analogues (BA) do not take part in the analysis carried out by the solver — the forces in their sections are computed according to the forces in the initial FEs. The forces may be computed in different elements: bars, plates, solids, special elements, and all possible combinations of such elements. Then, analysis of reinforcement and analysis of steel sections for bar analogues is carried out as for the main elements of the model.
The section with arbitrary shape and components from the Cross-section Design Toolkit module can be assigned to bars in BAs. Then, it is possible to return the acting forces from the analysis results to the Cross-section Design Toolkit module in order to carry out verification analysis of the bearing capacity of such section by nonlinear deformation model.