Features What's new in LIRA-SAPR 2020

Autodesk Revit

New version introduces enhanced options of two-way integration with Autodesk Revit:

• export from Revit with the option to select part of the model that should be transferred to LIRA-SAPR. It saves time significantly when developing a project of combined systems as well as multi-section buildings / structures. It will also be useful for any local calculations;
• new option to transfer distributed loads across an area with holes, as well as with different variants for nesting levels of the load contours (e.g. the live load on the floor slab is applied across the whole area, while the internal load contour for the stair-elevator joint is defined with a load of different intensity);
• import of curvilinear walls;
• export of the output data with selected reinforcement only for the part of design model.

Tekla Structures 2019(i)

Two-way converter Tekla Structures 2019(³) – LIRA-SAPR – Tekla Structures 2019(³). It enables the user to carry out complete analysis and desifn of steel and RC sructures.

*.SLI

Loads applied to plate elements and distributed across the trapezium are added to algorithm for import/export *.SLI files.

*.SAF

Import of *.SAF files: development is started (analytical model ArchiCAD/Allplan)

Input tables

New options are available for input tables:

• data may be transferred between active problem files;
• new tables where the user could define parameters for elastic foundation (subgrade moduli for plate FEs, bar FEs and specific elements for simulating the soil resistance outside the foundation plate);
• tables where the user could define the stiffness of the elements in the model (standard, steel, steel & reinforced concrete and numerical types of stiffness) and parameters that describe nonlinear stress-strain diagrams for the main and reinforcing materials;
• API tools are provided for all available tables.

Collection of loads

In addition to previous options to automatically collect wind loads, generate pulsation load cases, define earthquake and generate moving load, in version 2020 there is an option define automatically the snow mound, ice load, soil pressure onto the walls of the basement. Enhanced options to generate the wind load, option to generate load according to Eurocode EN 1991-1-4:2005 and NP 2.2.1 to SP RK EN 1991-1-4:2005/2011. It is also possible to automatically collect loads on beams.

Analysis of load from the snow mound is carried out for the 2D roof with parapet and roof parts that are adjacent to the ventilation shafts that rise above the roof and other superstructures. The load is computed according to the following building codes: SNIP 2.01.07-85, SP 20.13330.2016, DBN B.2.1.2-2006 3.1(2007), NP to SP RK EN 1991-1-1:2003/2011. The load value depends on the snow region, height of the structure above the roof, coefficient taking into account the snow drift and thermal coefficient. Width of the snow mound is calculated automatically. Optionally, you can apply snow load to the space across the whole site limited by the contour and the snow mound. The contours of the structures above the roof may be arbitrary. The load from the snow mounds is automatically transformed into the surface load.

The ice load is computed according to SP 20.13330.2016 according to the ice thickness, height of the structure and element sections. The ice load is automatically applied to bars of the structure (when the meshed model is generated) and is automatically updated (when either parameters of ice load or geometry of physical model are modified).

Intensity of soil pressure is computed by Manual on design of retaining walls and basement walls (Reference manual to SNIP 2.09.03-85) according to specified parameters: unit weight of backfill soil, angle of internal friction, unit cohesion of backfill soil, slope angle of design plane (wall, sheet piling), slope angle of the soil surface and friction angle of the soil in contact with design plane, grade elevation, ground water table and uniformly distributed load applied to surface. After analysis, three load cases are generated. They include intensity of the active soil pressure, intensity of additional horizontal soil pressure due to the groundwater, and intensity of the horizontal soil pressure from the uniformly distributed load located on the surface of the failure wedge. Computed soil pressure is applied to the previously selected walls in the underground part of the building. Optionally, you can generate one load case with all three loads. If it is necessary, to modify the load from the soil, you could modify the pressure and update the meshed model - the load from the soil will be updated automatically. It is possible to generate several sets of input data to compute the soil pressure values.

New tool that enables the user to collect loads from the slab surface and redistribute it to beams. The input data contains load that should be transformed to linear one and applied to load-bearing beams. Then select beam supports, select the load case from which the load should be collected and the load case where redistributed loads should be applied to, define the method for load visualization – linear loads or equivalent concentrated loads. Redistributed loads may be applied not only to the meshed model but as the input data for the physical model as well; it enables the user to carry out such analysis and do not miss created load on beams in further updates of the meshed model. Beam structural system may have arbitrary shape.

For the wind load, in addition to the option to collect and apply the load at the level of floor slabs, there is the option to apply 3D wind pressure to the whole structure.

Option to snap the load to the storey bottom/top and to additional levels. When the elevation or the storey height is modified, or the elevation of additional levels is modified, these modifications will be considered in the load.

Enhanced options for the 'Attach object' command. Now it is possible to 'attach' load along the contour (with or without relocation from contour borders). When the contour of the main object is modified, the load is also modified. To the whole object – when the overall dimension of the main object is modified, the load will reproduce its contour. By object level – when the elevation of the main object is modified, the load will 'follow' the object.

New option to generate design combinations of loads (DCL) according to EN 1991-1-4:2005.

In properties for the project, three safety factors are added: for the ultimate and serviceability limit states, and for emergency combination (for DBN). Safety factors are transferred to appropriate cells in the DCF table and DCL table in VISOR-SAPR module.

Triangulation

• All methods of triangulation are speeded up due to multithreaded environment. The speed depends on the number of physical processor cores. Triangulation of every new plate is a separate process, so all cores of computer are used. For the 'Quadrilateral' triangulation, there is new parameters 'Fast mesh generation'; it further accelerates the process.
• In previous versions, triangulation of slabs with large area took much time. In version 2020, for such cases, a new option appeared in the properties of the user-defined triangulation line - cutting line. This option assumes that the slab will be cut into separate parts along this triangulation line. Triangulation of such parts will be much faster.

• For user-defined triangulation lines, it is now possible to define division (approximation step) inside the line. For triangulation lines there are expanded options to copy, symmetry, both within the same floor slab and for other slabs in the building. Thus, it is possible to define a template from the triangulation lines, then save this template to the SAPFIR library and use further in both current and other projects.
• In properties for openings (windows and doors), new option to create horizontal and vertical triangulation lines. This option enables the user to crate rays from the opening up to the wall edges from characteristic lines that will be further used as levelling lines for triangulation.
• Triangulation step may be defined denser for the near-support zone, for example, floor slab to column connection. In column properties now you could define the step for triangulation points that will be use near support, number of rows for points with fixed step and total number of rows for triangulation points. After the rows with the fixed triangulation step, the program creates several rows with transitional step in order to moderate transition from the dense mesh above the support to the sparse mesh in the span.

Finite elements

In SAPFIR 2020, one more step has been taken to generate complete meshed model without VISOR-SAPR module. It is possible to define explicitly FE 55 for simulating elastic spring, FE 62 for damping elements, FE 10 numerical for arbitrary 3D bar, FE 56 for 1-node FE. For all special FEs, stiffness is defined and the intersection is made automatically when the meshed model is generated.

For the objects of wall and slab type it is possible to select the type of FE that will simulate this object: FE 44/42 – shell, FE 19/12 – slab, FE 27/24 – arbitrary wall-beam, FE 30/22 – wall-beam, FE 47/46 – thick shell, FE 17/16 – thick slab, FE 59/58 (FE 258/259) – linear and nonlinear elements of platform joint, FE 344/342 – geometrically nonlinear shell, and orthotropic FE of shell, slab, wall-beam. For the objects of column and beam type it is possible to select the following FE types: FE 1, 2, 3, 4, bar FE of 2D truss, frame, grillage and 3D truss, FE 7 – 3D bar thin-walled FE with account of warping in the section, FE 10 – arbitrary 3D bar, FE 207-208 – physically nonlinear 2-node FE of precompression and pretension, FE 310 – geometrically nonlinear arbitrary 3D bar (cable). To selected FE type you could assign stiffness explicitly in VISOR-SAPR terms and the comments to the stiffness.

For a foundation slab on natural soil, it is possible to define the stiffness for horizontal springs or to calculate it automatically. As a result, FE 56 are created at nodes of the foundation slab; they simulate the friction between concrete and the soil. To calculate the stiffness of FE 56, the coefficient of friction between concrete and the soil and the allowable static deformation are defined. It is possible to limit the number of calculated stiffness values. Soil pressure Pz may be either numerically specified or calculated according to DCL.

Analytical model

• New option to align one object for another. This command enables the user to generate accurate analytical model if the physical (architectural) model was generated with certain inaccuracies.
• Curvilinear objects may be unified automatically, for example, curvilinear slab by curvilinear wall. It enables the user to obtain the same unified approximation step for objects when he meshed model is generated. And then a regular triangulation mesh as well.
• Parametric beam system (array of beams) may be generated. The step and section of beams are defined in both directions. For every group of beams, a complete set of beam parameters is available. Beam system may be of arbitrary shape, horizontal or inclined. The slope angle of the beam system depends on the direction vector. In a regular step it is possible to define an individual step, different from the general one. Optionally, loads on beams may be defined. The load may be either distributed along the contour (then it will be collected on beams with appropriate algorithm) or linearly distributed along each beam.

• Elements in the meshed model may be intersected by actual volumes of objects. New settings for intersections enable the user not to worry about such parameters as ration of pylon sides, precision for search of intersections and other detailed settings for intersections.
• Number of design sections of bars in columns, beams and elements of trusses may be defined. Number of sections may be defined either for all projects (in SAPFIR settings) or individually for every object.
• Lintel above the opening in wall may be defined automatically. You could define all necessary data for more accurate simulation of this model fragment (section of lintel, material, indents from opening). Lintel is automatically updated when you edit dimensions of the opening.

• New option to simulate the strip foundation with the Wall and Beam tools. For selected walls, define the width, height of the strip, material and the necessary design parameters. Click the Create button to generate the strip foundation that is connected to an existing wall. When the wall is modified, the foundation is automatically updated.

• For windows and doors, new method of generation 'by line segment' is added. It enables you to graphically define the width of the opening (it is helpful when openings are generated on *.dxf underlays).
• New command 'Move to current storey'; it saves the geometric location of the object in the space. The object is moved only within the project structure by storeys if by mistake the object was generated on another storey.
• For the 'Eye drop properties' command, new option to apply the copied properties to the group of objects.
• Triangulation of the capital is modified. Now the capital is triangulated with triangulation step for the slab if an individual triangulation (different from triangulation of the whole model) was defined for this slab.

Analysis results in SAPFIR

From version 2020, the meshed model generated in SAPFIR may be sent to the solver for analysis directly from SAPFIR module. After analysis you will be able to preview and evaluate analysis results, such as: mosaic plots of displacements at nodes along all 6 directions, mosaic plots of stresses in plates (normal, shear stresses, moments, shear forces and soil pressure), mosaic plots of forces in bars (longitudinal, transverse forces, moments and soil pressure Ry, Rz) and mosaic plots of forces in 1-node elements in all 6 directions. Initial evaluation of the stress-strain state of the structure enables you to avoid errors in the meshed model and correct them in SAPFIR environment. The meshed model may be displayed both in the initial and deformed shape. The scale of deformations, the size of the nodes, the line thickness on the mosaic plots and the number of ranges within the scale are defined. It is possible to output results by the generated DCL and load cases.

Generator

• The new node is added: Block of Models. It enables the user to create the so-called Standard block. In such block, you can add objects from the SAPFIR graphic environment or any object created with nodes. Further, the Block of models may be duplicated by storeys, copy, make symmetry, etc. When initial block is modified, all other copies of the block are updated automatically. Such modifications contain both edit options (add a new object to the block, move object, delete) and modifications in properties of the objects included in the block.

• New nodes are added: node to generate the strip foundation under the walls, node to generate lintel above the opening, node to generate the grid lines.
• New dialog box 'Update underlay' ( dxf and obj) to quickly update selected underlays and do not open the Generator dialog box.
• There is a node for filter by criteria. The following data may be defined as criteria: length, height of object, thickness, material, relocation from level, type of object, layer, tag.
• Node for import of *.ifc model. In the node you should define the path to the *.ifc file. Node for import of *.ifc file is updated dynamically. Any modification in the *.ifc file will be displayed in SAPFIR automatically when you activate the 'Update model' command. Modified, deleted or added objects are presented in different colours in SAPFIR environment. Modified objects are coloured green, added - blue, deleted - red. That's why it is possible to track changes in *.ifc file directly in SAPFIR.

Design of RC structures

In addition to the previous systems Slab, Diaphragm, Column, Beam and Dowels from the base slab, design of straight RC stairs is added to Design of RC structures module. Based on the information (about reinforcement) imported from VISOR-SAPR, the stairs may be unified.

The stairs are designed automatically. The program generates the reinforcement view that contains sectional elevation of a flight of stairs with main longitudinal reinforcement and additional reinforcement. The working drawing of reinforcement is generated for the staircase together with the schedule, list of components and list of steel consumption.

Large panel buildings

• To calculate stiffness of the horizontal joint, input data may be defined manually (as alternative to obtaining the input data from the physical model). Thus, you can define appropriate values for the cubic strength of the mortar, thickness of the upper and lower mortar joint and the wall thickness. The values of the sigma-epsilon diagram will be calculated according to the specified data.
• For the horizontal joint, new method is added. Floor slabs are supported with account of eccentricity using FE 10.
• New method to visualize models as storeys with a shift. You can control relocation along the X, Y or Z-axes with special sliders.
• It is possible to visually check correctness of the input data in the 'Stiffness analysis of joint' dialog box.

• Much enhanced options to define and edit loads based on interaction VISOR – SAPFIR – VISOR. Due to such interaction, there is new option to transfer part of the model or the whole model to create new or edit available loads with SAPFIR tools. New tool may be also used to collect wind loads, snow loads, soil pressure onto any design model generated in VISOR-SAPR module or imported from any allowed format. Now all surface loads applied to bars and plates save information about the contour vertices (projection line). Geometry and location of the contour may be modified at any moment when you work with design model. Presentation of load contour helps the user to evaluate the loads (defined for the model) as mosaic plots and significantly improves quality for documentation of the analysis input data.
• To evaluate analysis results, mosaic and contour plots of full translational displacements (displacement vector) are added.
• Unification angle for axes to generate the stresses and axes for orthotropic plates now is presented as prperty. That is, when you modify the mesh of plate FEs or the plate geometry, unification angle retains its location.

• The input data of the DCF/DCL tables for building codes (SNIP 2.01.07-85*, SP 20.13330.2016, DBN B.1.2-2:2006) is expanded with safety factors for buildings and structures.

• New version supports interactive analysis protocol. In case of any warnings, errors, residual errors during analysis procedure, the information from analysis protocol is automatically placed to the service window 'Errors and warnings'. So, there is an option to select nodes and elements without PolyFilter. For example, it is possible to quickly select nodes with considerable residual error or select destructed elements of the model, etc. by highlighting one or several rows in appropriate window.

• New option to copy and paste selected fragment from one model into another and do not specify reference nodes for merge procedure. When this command is applied, the models are merged in gnlobal coordinate system. This option is helpful when several engineers work with the same project. It is also possible to paste the certain fragment and automatically search for intersections.
• Hinges in bars may be assigned based on selected nodes. Hinges may be also assigned at the end of structural elements. To check the design model and prepare documentation, there is 'mosaic plot for parameters of hinges' where you could see all assigned combinations in colour.

• New option to save all defined dimension chains when you use the 'Geometric properties' dialog box. Dimension lines do not disappear when the model is redrawn. It is possible to cancel the last dimension line or cancel all defined dimensions. New option to present values of dimension lines with account of projection view.
• For 2D problem that contains physically nonlinear soil FE (281-284), it is possible to compute stability factors for every FE. They are computed according to principal stresses and strength parameters defined in stiffness for geological element (GE).
• New option to define names for histories of nonlinear load case. When intermediate results of nonlinear analysis are displayed, on the screen you will see the value for summary coefficient to load.
• For standard types of sections for bars, new option to define the Poisson's ratio. In previous versions, the value equal to 0.25 was used in analysis on shear for these types of sections.
• New option to save the edit parameters in the dialog box. Appropriate oprion is added in the 'Parameters to edit and visualize' dialog box, 'General' tab.
• New option to work simultaneously in the 'Create dynamic load cases from the static ones' and 'Edit load cases' dialog boxes. In the first dialog box there is an option to organize the table rows by certain criteria.
• No limitations on prerequisites to generate the input data for problems with 'Time history analysis'. In previous versions, it was necessary to folloe the strict rule to generate load cases in design model (the first load case – pre-history, the second one – load case with masses, the third one – dnamic loads and the fourth optional load case – damping forces). Now the user could indicate the numbers of these load cases.

• Mosaic plots with wiehgts of masses are provided for dynamic problems. These mosaic plots may be used to evaluate analysis results and to prepare documentation.
• Number of the group of coupled DOF contains information about number of nodes included into this group.
• Mosaic plot with 'number of design sections' is available for bars.
• Enhanced options in the 'Diagram along section' dialog box:
  • presentation of max values, values in every FE;
  • rotation in the 'Diagram along section' dialog box with the right mouse button.
• Option to hide or show the grid lines during fragmentation of the model.
• To check the input data in fire resistance analysis for RC structures, section edges subjected to heating will be coloured red. In the 3D view mode (3D-graphics) with account of assigned sections it s also possible to check fire conditions for plate elements.
• New way to visualize the model - generation of 'Contour lines of plates and edges of solids'. This command may be used together with presentation of edges for slabs and solids and without sych presentation. It may be also used with previous commands for visyalization ('Without invisible lines', 'Shading', 'Stiffness in colour', etc.) and with mosaic/contour plots. You can also define the 'Smoothing angle for surface' (in degrees) to determine contour lines and modify thickness of contour lines for plates and edges of solids.
  When the 'Contour lines of plates and edges of solids' command is active, the contour of elements that overlap (belong to the same plane) or intersect is also visualized.
• Decimal symbol is automatically corrected (from comma to point) when you define input data in the table part of dialog boxes: 'DCL', 'DCF', 'Regular fragments and grids', '3D frames', 'Nonlinear stress-strain diagrams', 'Colour grade visualization', 'Summarize loads', 'NL Engineering'; SOIL system ('Grids', 'Boreholes', 'Table of boreholes', 'Soil properties'), etc. In the above-mentioned dialog boxes, you could work with formula in selected cell. To define the formula for certain cell, make the cell active and input the equal sign. When you define the formula, press ENTER. The result of calculation will be displayed in the cell.
• In the 'Transform mesh of plate FE' dialog box (on the 'Edit transformation' tab), you can use as vertices not only nodes that belong to FEs or 'dangling' nodes but the grid nodes as well.
• New option to delete the load from selected elements and nodes in all load cases of design model.
• Mosaic plots of nonlinear stiffness for FE 255 - 2-node FE of elastic springs with account of ultimate forces (Rx, Ry, Rz, Ruõ, Ruy, Ruz).
• Mosaic plot for the area of punching shear reinforcement per running metre of perimeter. This plot clearly illustrates the intensity of reinforcement.
• For new modules 'Bar analogues' and 'Progressive collapse', new user-friendly graphic interface to define the input data, evaluate analysis results and prepare documentation.
• Information about nodes and elements of design model is updated, there are new information tabs that describe the input/output data for new types of analyses.
• In the 'Pack model' dialog box, new parameter 'ignore nodes of bar analogues'. It helps the user to avoid 'throwing together' the nodes of target elements in bar analogues and nodes of other elements in the model.

• New version of LIRA-FEM program presents high-precision (with nodes on sides) linear finite elements (plates and solids). With these elements the program significantly improves the solution accuracy even with coarse mesh.
• The sixth degree of freedom (DOF) for the shell is realized – rotation about the axis perpendicular to the plane of the plate. With new DOF the program improves the quality of the FE model when solving certain problems (to simulate mass eccentricity, to avoid geometrically unstable models, etc.) without mandatory use of special simulation techniques. Appropriate setting is added to analysis parameters.
• To solve dynamic problems with the spectrum method, an algorithm of mass condensation is implemented; it can significantly reduce the time to search for mode shapes. In this approach when mode shapes are searched for, only masses of the main structure are considered, while masses from the flexible part (for this problem the user is not interested in natural vibrations of this part) are concentrated at the common nodes. Eccentricities for account of torsion may be assigned to the nodes where mass condensation is performed.

• An alternative method of summing up components during earthquake analysis is implemented. This algorithm enables you to consider the proximity of frequencies and recommendations of many regulatory documents in analysis & design of earthquake-resistant construction, for example, formula (5.9) mentioned in paragraph 5.11 of SP 14.13330.2018.
• New dynamics module is introduced according to the spectra NTP RK 08-01.1-2017 'Design of earthquake-resistant buildings and structures', referred to by NP to the SP RK EN 1998-1: 2004/2012 (R2).
• New option to carry out 'Time History Analysis' after using the ASSEMBLAGE system or 'Step-type nonlinearity'. That is, it is possible to take into account the stress-strain states of structures before dynamic load due to the generation the history of loading / erection.

• New variant of the iterative behaviour of the FE of joint is introduced. With this variant it is possible to avoid the disadvantages of the step-type analysis method. The iterative method has the following advantages: the element is turned off in uplifting, the element is turned on when direction of load is changed, the force in iterative element will not be greater than allowed one. See demonstration "Analysis of large panel buildings in LIRA-SAPR' (slide 21)
• For iterative and step-type FEs of the platform joint, shear stiffness may be corrected depending on the vertical deformation.
• For problems with 'Time history analysis', load cases with dynamic loads, masses and damping forces may have arbitrary numbers.
• It is possible to define the local failure to elements in problems with 'Time history analysis' (option is available with the new system 'Progressive collapse').

• Enhanced options for solving problems by the iterative method. In the analysis you can use:
  • 'Method 1' – classic method of compensating loads;
  • 'Method 2' – modified method of compensating loads, it is recommended to use this method for problems with structural nonlinearity;
  • 'Auto select' – convergence rate is evaluated during analysis and appropriate method for solution is selected.
• New types of FE: 245, 246 and 247 (physically nonlinear analogues for FE of thick shell).

• The new version presents an alternative algorithm for analysis of masonry reinforcing structures in strict compliance with SP 15.13330.2012 (amendment No.3). Appropriate setting is placed in set of properties for design options. New user interface has been developed to describe the design parameters of masonry and mesh reinforcement.
• With new analysis algorithm it is possible to carry out analysis by ultimate limit state (ULS) and by serviceability limit state (SLS) for piers with rectangular section only. Analysis of piers with arbitrary cross-section may be carried out with a previously implemented algorithm that is based on a nonlinear deformation model of masonry.
• To generate rectangular piers, a new method is introduced to generate groups within the design level. The group is a set of zones (walls/segments) that form the shape of design section for a pier. To define the shape for the pier, use the 'General settings/Brickwork' dialog box.
• According to Recommendations on design of masonry structures strengthened with basalt mesh produced by JSC 'STEKLONIT' developed by TSNIISK named after V.A.Kucherenko, analysis with account of composite mesh is introduced in LIRA-SAPR 2020.

• Analysis of piers with arbitrary cross-section is enhanced. The area of compressed zone in the section is determined according to the deformation model, so the nonlinear behaviour of the brickwork is considered. In this case, more accurate analysis of the geometry of pier is carried out; it enables you to correctly compute the flexibility of the pier, the distance from the gravity centre to the section edge, as well as other geometric properties.
• New option to generate a report file in which all the intermediate analysis results are indicated, the geometric properties of piers for each combination of forces, as well as values of ultimate strain and stress for a nonlinear deformation model for each pier.
• Analysis of pier is also enhanced taking account of strengthening with steel casing, RC casing and reinforced plaster. Analysis is carried out in accordance with the Manual on the design of masonry and masonry reinforcing structures to SNIP II-22-81 (chapter 5).
• To check materials defined to plate elements of the model and prepare documentation, use the corresponding mosaic plot on the 'Geometric & Properties' panel.

• In new version LIRA-SAPR 2020 there is further development for analysis of reinforced concrete structures on fire resistance.
  • In bars and plate elements it is possible to determine required area of transverse reinforcement from analysis on fire resistance.
  • For bars it is possible to analyse longitudinal reinforcement for all types of cross-sections.


Standard types of sections for which you could carry out analysis of reinforcement with account of fire resistance
• For 'momentless' diaphragms, analysis of reinforcement in the middle of the element is provided. It is very practical for 3D volumetric construction (very thin wall with central reinforcement).


How to define the distance to gravity centre of the longitudinal reinforcement in the middle
• To evaluate the pilot reinforcement, it is possible to display the output data (reserve factors) for 5 different check procedures.


Output data from analysis of pilot reinforcement (PR) for plate elements
• All checks for the pilot reinforcement are greatly accelerated due to the option to define the search range.
• For Eurocode and similar codes, it is possible to carry out punching shear analysis of reinforcement with account of longitudinal main reinforcement.


How to define the input data for punching shear analysis of transverse reinforcement with account of longitudinal reinforcement
• All above-mentioned options are provided for the LARM-SAPR module as well (local reinforcement of separate elements in design model of the structure).

• When the output data from analysis of transverse reinforcement is displayed as coloured mosaic plots, the colour palette settings are presented in details. It greatly simplifies the evaluation and speeds up the transferring of the output data to design:

for plates

for bars

for punching shear

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.

New specialized system that complies with current recommendations for simulation of behaviour of building structures in case of emergency actions that cause local destruction of certain load-bearing elements.

Analysis may be carried out by:

• quasi-static method in linear and nonlinear settings. The ASSEMBLAGE system is used. Reactions from deleted element are applied to the model with the opposite sign and with account of dynamic factors.
• dynamic method of direct integration for equations of motion in time in linear and nonlinear settings. Analysis may be carried out with account of the loading/erection history. The final stage of erection is the automatic generation and application of the impulse load at certain period of time. This method also enables you to consider the damping effects.

One of results of the analysis is the forces computed in all elements of the model. They may be used to carry out structural analyses. For linear design models, in addition to the option to check the bearing capacity of sections, it is also possible to carry out analysis of reinforcement and analysis of steel sections.

Thus, after numerical simulation, the user will obtain a qualitative evaluation of the structural stability to progressive collapse. The user will be able to compare various collapse scenarios in order to identify the weak points.