Generating and modifying the model

The LIRA-CAD module implements an effective mechanism for managing design options. The new LIRA-CAD functionality allows you to create and modify design options and customise their parameters. Alternative design options allow for quickly obtaining the analysis results for reinforcement and sections according to different building codes. For each selected building code, structural elements automatically receive material properties corresponding to these documents.

Certain types of analysis (by DCF, by DCL, or by forces) may be assigned to every design option. The corresponding building code may be defined for any analysis (reinforced concrete, steel, or masonry reinforcing). Accordingly, the material properties specified for each of the selected building codes will be applied.

In addition, it is possible to create several design options according to one building code, with different types of analysis for sections (by DCF, DCL, or forces). These options may be selected in the dialog box and displayed in the table with design options.

The new approach of working with design options exactly corresponds to the logic of structural analysis software VISOR module. The input data required to carry out the strength analysis may be defined in more detail. 

• New module for earthquake load - (63) TBEC-2018 (Turkey).
• A load from a forced displacement may be defined. The following data should be defined: the load, its displacement (m) along a certain direction, its rotation angle (rad) about a certain axis, or its warping (rad/m). When the load from the forced displacement is located in the model, it is automatically linked to the object that it is applied to. To check the object that the load is linked to or remove such a link, use the "Manage links of object" dialog box. To "fix" (link) the load to a selected object, use the "Attach object" command. When the meshed model is generated, a node is generated at the location of the load from the forced displacement, and such load is transferred to the VISOR module as a forced displacement at the node. To define the load along the line, use the "Forced displacement along line" command. In the meshed model, such a "linear" load will be split into several nodal loads of the forced displacement with the triangulation step of the object that it is linked to, or discretization step (if such a step was defined in the load properties). 
• New tool to define uniform and non-uniform thermal loads on bars and plates.

• For dynamic analysis, new option to define the mass weight at a node and mass weight along a line.
• Enhanced functionality for the tool that collects loads. New option that takes into account continuity of the proxy object when distributing bar loads through it.
• For objects of the "Snow mound" type, new option to divide the snow model into segments and connect the separate segments together.
• For more convenient work with linear and surface uniformly distributed loads, a new approach to their application in the finite element model is provided. New option "By whole finite element" for uniformly distributed loads: the load may be transferred not as individual concentrated load but as uniformly distributed over the whole surface of each finite element. To use this option, the load should be linked to a certain structural element. This option is available for the surface load and the linear load. There are two ways to transform the load that is applied to each finite element:
  • the load contour defines the triangulation zone. In this case, the load is presented as a uniformly distributed load within this zone;
  • the triangulation does not depend on the load contour. In this variant, the load is transformed into a uniformly distributed load on the plates in which centres of gravity are located within the load area.

• For walls that are interpreted as loads, there are two methods to transform this load:

  • 1 (standard method): to calculate the weight of the wall with account of openings and create a uniformly distributed linear load that is placed along the line along which the partition is generated;
  • 2 (new method): to divide the wall into segments with variable load within the openings. Then each segment will obtain a different, uniformly distributed linear load corresponding to that segment.

• The "Space" tool is significantly enhanced:
  • If it is necessary to consider the floor for the room that is described as a load and a multi-layer floor covering material is used, the intensity of this load will be automatically calculated, taking into account the thickness and unit weight of each floor covering layer;
  • If a room occupies several floors and is interpreted as a load in a property, the intensity of the load will be applied to each slab that it passes through, taking into account its volume.
• The validation of the model is enhanced. Upon generating a mesh model, the software will check the loads to identify the finite elements that it can be applied to. A warning message appears if no finite elements are detected and some load is lost. Therefore, in order to prevent lost loads during the model's transfer to the VISOR structural analysis module, it is possible to adjust the load locations during the generation of the meshed model.  The project properties now include a customisable parameter that allows you to ignore a small percentage of the lost load and not display a warning when validating the model.

• In the "Truss parameters" dialog box, there is a new way of dividing the bottom and top chord of the truss taking into account the location of the web. There is also a new parameter: "STC function". This parameter allows you to display the functional purpose of the truss element when the truss is exploded. It will also be displayed in the steel table.

• In the "Retaining wall" element, a new type of alignment for the analytical model (Left) is added. Also the "Arbitrary snap" option is added to the "Level snap" parameter.

• Fixed bug: the stairs did not reach the wall horizontally.

• Fixed bug: in selecting "Other" elements when using the "Select Up" command.

• Improved "Cancel" tool: fixed bug when properties are assigned to objects.

• The "Design options" dialog box is enhanced. If several design options with completely identical input data are specified in the dialog box, the program will check and display a warning about it.

• Enhanced algorithm for assigning more than one type of pilot reinforcement (PR) to columns.

• Modified and improved algorithms for finding intersections of objects:

• Corrected function: determining the interposition for a rib of a beam side surface and a rectangle of column surface. In some cases, unnecessary intersections were created.

• In the functions of intersection between real volumes, the search parameter assigned to elements is used. Until now, in some cases it was taken from the settings for the meshed model and the setting assigned to elements was ignored.

• Fixed for plates. The "Real volumes" worked only if they were assigned to both elements, otherwise the simplified method "By axial lines and volumes" was applied. Now if a "Real volumes" intersection option is defined for either of the two elements, this option will be applied.

• Corrected algorithm for intersection of surfaces. Fixed bug: creation of unnecessary PRBs. So, in some cases it was not possible to transfer the model to LIRA-FEM.

• Fixed bug: visual isolation of Shafts in the analytical presentation of the model. When activating the "Current storey" command, the shafts were displayed on all storeys.

• New option to define the input data for the dynamics module (32) of SNRA 20.04-2020, Republic of Armenia.

• Optimised process of load application to the object: fixed bug when the concentrated load applied to the column was not applied to the object in the meshed model.

• L and R search parameters are added for wall, column, beam and slab objects with the "Load" interpretation.

• Enhanced mode for visualisation of the current storey for space loads in the physical and analytical presentation of the model.

• Fixed bug: incorrect designation for direction of the "Soil pressure" in the architectural and meshed models.

• Clarified option to transfer the uniformly distributed loads on bars when the "By whole finite element" option is selected.

• Added option: to define multiple special loads for elements rather than one as in previous releases of the program.

• Enhanced algorithm for distribution of dead weight of elements to different load cases. Unlike previous versions, when the load from dead weight could only be placed into a duplicate dead weight load case, it is now possible to place the load from dead weight into any load case.

• In the "Create new meshed model" dialog box, there is a new command that allows you to customize parameters of a new meshed model. The previously specified data may be saved.

• The transfer of the meshed model from LIRA-CAD module to VISOR module is accelerated. The speed of saving option varies and depends on the content of the model. On average, the meshed model is transferred to VISOR module 3-5 times faster than in previous versions of LIRA-CAD module.

• 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.

• The mirror copy command is improved, taking into account the correct location of the cross-section in the elements and the boundary conditions assigned to them.

• The soil model now has a new option that allows it to be temporarily disabled during calculations. It is not required to exclude the soil model from the project in order to identify the best possible design options. Instead, you could activate an option that will ignore the soil model in calculations. This offers a more practical and adaptable method of using the soil model.

• A number of new features are developed in the "Layers" dialog box:
  • for more convenient work, layers may be automatically organized by name;
  • when the underlays are imported, the colours of the layers used in the DWG file fully correspond to the colours in LIRA-CAD module;
  • to check that the layers belong to certain objects, a special graphical view "Layer Colours" is developed.

• We have changed how the parameter value for the ±DH is interpreted in response to many requests from our users. This tool's original purpose was to simulate niches and recesses. That is why the "Depth" parameter was made for it in the interface. The deeper the niche, the higher the parameter value. Many users have discovered an additional application for this tool, though. It was possible to represent pedestals for columns, local thickenings in slabs, and capitals by specifying negative depth values. It's challenging to classify these components as niches. Consequently, the ±DH was introduced instead of the term "Niche," which frequently received a negative depth value.

  Since a positive sign is associated with an increase in thickness and a negative sign - vice versa, it was decided to name the parameter "Thickening" and interpret it accordingly. Now, at negative values of this parameter, the thickness of the slab decreases and accordingly, a niche is formed. At positive values - a local thickening of the slab element is formed.

• In the design of buildings, there is the practice of placing elements at intermediate elevations located between the main levels of the building. To facilitate the work with such objects at certain heights, there is a tool to create "intermediate levels". In the new version of the software, in the "Project Structure" dialog box for such objects, you will see indicators of height elevations, thus facilitating the management of structures placed at different height elevations.

• To facilitate the work process, the key tolerance settings required for the project are now gathered in the project properties window. These tolerance settings are important at various stages of the program: they are used for model generation, during the import of external models, during the design of panel buildings, and when the complete model is checked for errors and warnings. The design process is more standardised and predictable when these characteristics are all in one location, which reduces errors and speeds up the design process.

• The key tolerance settings required for the project are presented in the project properties window. These properties are used in a number of cases:

  • for model generation;
  • when importing models;
  • in the construction of panel buildings;
  • for validation of the generated model.

• The "Shaft" tool is improved. New functionalities:

  • check points are added at the top of the object to make it easier to resize the shaft;
  • for more convenient and accurate generation it is now possible to display the shaft in the analytical presentation of the model;
  • in the "Editable Analytics" mode, the option to change the shaft size is now available;
  • for the shaft element, the "Extract properties" tool is improved and applied; it allows you to copy properties and apply them to other created objects.