Subproblems

New technology to define the input data for the Subproblem method. With this technology, many independent sets of subgrade moduli and sets of coefficients to modulus of elasticity can be used in a single design model.

Each loading stage may have a different set of parameters based on the subgrade's properties or maintenance conditions. Therefore, the soil's heterogeneity and the unique features of the foundation-structure interaction may be taken into account; this allows for a more realistic description of the system's actual conditions.

Furthermore, the flexibility to assign different coefficients to the modulus of elasticity at every stage of analysis creates additional opportunities for more precise design solutions.

Input data for the stability analysis

In the new version of LIRA-CAD module, it is possible to define the input data for stability analysis of structures. Users can define key parameters and select objects for analysis. Main options:

• To select the calculation method: by forces or by DCLs.
• To define load cases: either loads or DCLs to be considered in the analysis procedure.
• To include elements in the analysis: in the properties of objects you could define whether they are considered in stability analysis.

The defined parameters are automatically transferred to LIRA-FEM. So, it eliminates the re-entry of data, reducing the risk of errors and speeding up the modelling and analysis process.

Condensation of masses

New option to define the Condensation of masses to optimise dynamic analyses, especially when analysing vibrations of structures. Only masses of the main structure are considered when searching for mode shapes, while the masses from the flexible part (masses of selected elements in which natural vibrations are not of interest to the user in this problem) are concentrated in its support nodes (support nodes of selected elements). Also, it is now possible to perform Selective account of masses in elements to consider exactly the masses of selected elements for dynamic analysis.

Unification of bars

New option to preliminary unify bar elements (beams and columns) for analysis of reinforcement or metal sections. In the Unify bars dialog box, all elements of the model are listed: columns, beams, as well as elements of trusses and beam systems. The table contains data about name of the element, its length, section and material. Unification can be performed on the basis of tags assigned to elements, or unified groups of structural elements (UGSTE) can be created. A graphic presentation of elements by tag colours is available now. Unified groups (created on the basis of tags or assigned to UGSTEs) can be transferred to the VISOR module of the LIRA-FEM program.

The unification table in its current state can be placed on the drawing as an editable table. You can also export its contents in TXT or CSV formats for Microsoft Excel.

Perfectly rigid bodies (PRB)

In previous versions of the program, there was an option to arrange the combined behaviour of beams and slabs with the Offsets tool that provides a reliable connection between elements. In the new version, an additional option - Perfectly rigid bodies - is added, providing an alternative modelling strategy.

The length of the PRB is determined automatically based on the distance between the analytical models of objects and is updated in real time when any of them is moved. In the analytical representation mode, the PRB model more clearly demonstrates the interaction between the slab (plate) and the beam (bar).

With this approach, the interaction between beams and slabs can be described more precisely and adaptably, ensuring that they behave together as a single system. The use of Perfectly Rigid Bodies extends the functionality of the program, offering a new way of modelling such connections and increasing the accuracy of calculations.

Triangulation

Triangulation regions in the slab above the walls are updated when the walls are moved or modified. New option to update the dimensions of an existing triangulation zone and the step of approximation of its contour lines. In previous versions, it was necessary to delete the old triangulation zone and create a new one with updated parameters.

Triangulation points in the slab above/below the walls are created automatically for flexible customization of triangulation mesh. To manage the triangulation points, use the following parameters: step of triangulation points and number of rows. You can also specify the number of rows with fixed step of triangulation points. In this case the remaining rows will have a transitional step of triangulation points. The value of this transitional step can be in the range from fixed step to user-defined step of triangulation in the plate.

Additional grid of triangulation lines

To improve the accuracy in modelling of slab triangulation zones, a new tool Additional grid of triangulation lines is introduced. It allows the user to define the cells by which the slab is divided into finite elements, providing more detailed modelling.

Key options:

• To define parameters for the cell: The user specifies the dimensions of the cells to be used for triangulation.
• To select the triangulation zone: Define the slab on which the additional grid will be created.
• To define the generation method: Depending on the needs of the project, you can select different shapes for the additional zone: rectangle, sloping rectangle, inscribed or circumscribed polygon.
• To locate the additional zone: The tool allows you to place triangulation zones at key locations to create a denser and more accurate FE mesh.

Benefits:

• Easy to set up and use: The tool is intuitive and easy to set up.
• Visual clarity: The user can immediately see how the future triangulation mesh will look like.
• Modelling accuracy: Provides optimal densification of finite elements in important zones of the meshed model, improving the quality and accuracy of the analysis.

This tool simplifies the creation of complex meshes and allows for precise control of the finite element structure, especially in critical parts of the model.

• A new functionality has been introduced that allows you to precisely define the intersection line between the ramp and the curved wall it rests on or intersects with. This solution automatically creates the intersection line along the contour of the interaction between the two elements. In this way, an integrated coordination of the ramp with the curved wall is ensured, which contributes to a more correct connection between the ramp and the wall in both the physical and analytical models. Engineers can build complex curvilinear shapes much more easily thanks to this approach, which also increases modelling accuracy for complex elements.

• The new command "Do not intersect in the meshed model" allows you to configure (in the physical model) that two selected objects will not work together. The command is universal and may be applied to different types of objects. For example, to remove intersections between objects within the deformation joint. The configured intersection prohibitions can be checked in the "Manage links of object" dialog box.

• The program incorporates a new approach to verify if the ground-floor objects have supports. Links are automatically made for such vertical elements along specific directions in case there are no supports. In the new version of the program a check for the presence of foundation beams under such types of objects is added.
• A new option is to create a bar analogue for walls not only in a vertical direction (BA pylon) but also in a horizontal direction (BA wall-beam). For the bar analogue, it is possible to specify the number of division zones or the division step for the target bar.
• Depending on the load-bearing structure of the staircase (stair carriages, stair stringers, or monolithic reinforced concrete), the materials for the design of the stair elements may be defined. For the plates or bars of the stairs, it is possible to specify general parameters, parameters of concrete and reinforcement for analysis or steel class, design parameters, and selection limitations for the steel analysis.
• Unification of local axes of capital and column base. There are 3 options for the unification of local axes: globally, parallel to the global axes; along the floor slab, parallel to the local axes in the floor slab; and radially, parallel to the column centre.
• The Special Element tool is enhanced. Now you can manually define the coupled DOF and hinges between any objects.
• Triangulation points may be defined over columns and triangulation lines over walls in inclined slabs. It is also possible to create arbitrary points and triangulation lines on inclined slabs.
• New functionality to make it easier to create and edit walls. Additional points at the top of the wall are included in the tool. The new features provide more accurate positioning of walls and more reliable interaction with other elements at the same level.
• Additional design parameters are introduced to the building model; these parameters are utilised in the finite element analysis (FEA). Rz, the ultimate load on an elastic foundation in the direction of the local Z1-axis of the finite element, is a new parameter introduced to the foundation slab. This enhancement makes it possible for you to perform a nonlinear FEA and more precisely consider the impact of this parameter.
• The "Align model" tool is enhanced to align the wall's analytical component as well as its physical structure. This enhancement is available in both "Analytics" and "Editable analytics" modes. This option makes it possible to efficiently align the "analytics" of the wall with other objects and, as a result, obtain higher quality analytical model (of the building).

• The "Align model" functionality in the software is significantly improved not only for walls, but also for slabs. The slabs are aligned for both physical and analytical models. This not only speeds up the process of generating and modifying architectural and analytical building models, but also contributes to improving the accuracy and quality of the design.

• For stairs where the stair carriages are the load-bearing components, several modifications are made. The ability to define the design material parameters for reinforced concrete and steel is one of the modifications. It is feasible to configure the following settings for steel stair carriages:
  • element type;
  • partial safety factors and load factors;
  • presence of stiffening ribs;
  • deflection value;
  • input data for the stability analysis;
  • in the analysis of the cross-section, you can define the required dimensional limits and the program will carry out an analysis within the range.

• In LIRA-CAD 2024, it is possible to independently manage the combined behaviour of elements with the perfectly rigid body (PRB). There is a new option to generate PRB as a separate special element. This tool will allow you to create high-quality meshed models as well as more flexible management of the combined behaviour of elements. Generated PRBs can be copied by the element itself or to other elements. It is also possible to add a PRB as a template to the Library and use it in other projects.