iTWO structure 
FEM Concrete Slab Start

Start Package Concrete Slabs



New Features in iTWO structure fem

With the current version, the following adaptations and enhancements are available in iTWO structure fem, in addition to the adaptations to run under Windows®11, which make the use safer and more efficient:

Revit AddIn

  • The generation of models in which walls and beams intersect with each other and with the floor slabs has been fundamentally revised. The intersections are also taken into account when generating loads.
  • The transfer of joint information from Revit has been improved
  • The Revit AddIn has been reorganized for a better overview and operation. The functions are clearly arranged for quick access.
  • The "Check" tool can be used to check the calculation model created in Revit for modeling cleanliness.
  • Errors can be corrected with the Revit tool "Adjust model". The user can specify the tolerance for this model check.
  • The export to iTWO structure fem can be version-dependent and the assignments for the materials, cross-sections and all other settings can be managed on a project-specific or cross-project basis.

iTWO structure fem

  • The load input has been revised and extended for a comfortable generation of live loads as load trains.
  • The bending design can be carried out either at the column or wall border. SLS checks can now also be taken into account in the design.
  • The output list has been extended in various points. The size of predefined and user-defined pictures can now be set.
  • The project-related transfer of loads has been revised and improved.
  • In addition to the individual design states, the maximum required reinforcement and the associated governing checks can also be displayed in the output.

Whats new in iTWO structure fem?

  • Intuitive handling with intelligent work assistance
  • Transfer of analysis models with Revit Add-In
  • New design possibilities see AutoCAD
  • Object-related and context-oriented work
  • New possibilities for the transfer of loads
  • Consistent program solution from input to output
  • All functions and editing options at a glance
  • All results can be calculated in one operation if desired
  • Configurable program environment
  • New customizable output list with integrated graphics, new plot output

The efficient processing of slab systems is enormously important for us: iTWO structure fem allows fast input and output as well as simple post-processing of the systems. Working with 2 screens and 4K resolution is solved in an exemplary way! Matthias Tilke, Tilke Engineering Office - Olpe


Benefits of iTWO structure fem
Slab Package

  • Simple graphical input, if necessary with data transfer from CAD
  • Transfer of existing TRIMAS data
  • Fast training and efficient processing
  • All program functions at a glance
  • Consistent and integrated FE solution
  • Powerful calculation kernel
  • Reliable and well proven verifications
  • Clear and configurable results output with graphics
  • Repeatable result output for lists with graphics and plots
  • Fast and reliable evaluation of the load-bearing behaviour


Slab Package Start including following Modules:

iTWO structure fem Basis

The basic module of iTWO structure fem forms the basis for a number of different application possibilities of the new FEM solution from RIB for the processing of plates, walls, shells and spatial frame systems. The basic module enables the interaction of the various applications in a digital planning environment and also supports data exchange with other CAD and FEM systems. For an easy start, the application is limited to 100 beams and 1000 surface elements. The following functions are supported in detail by the basic module:

  • Intuitive handling with integrated working and learning aids and editing tips
  • Consistent program solution from input, calculation and design to evaluation
  • CAD-oriented design with graphic-interactive working method and 2D / 3D visualization
  • Context-sensitive and navigated design for all design elements and components
  • Object-related and context-oriented work
  • Transfer and transmission of object parameters to other similar objects
  • Complete undo / redo functionality during system input
  • Support of the processing by selection filters, display options and presets
  • Interfaces for ZEICON, DXF and DWG
  • New options for the transfer of loads
  • Windows®-oriented working with all functions at a glance
  • Configurable program environment with menu bar, object view and property tables
  • Parameterized standard profiles for all applications
  • Material database for standard-compliant material selection and self-defined material characteristics
  • Editing of the structure geometry in any construction planes
  • Measurement functions, text functions and measurement chains
  • Position and object name, object description and texts
  • Subsystem technology for clear structural modelling
  • New output list with integrated graphics and fully repeatable results output
  • Free configuration of result output with integration of text modules, images and XPS documents
  • User-defined definition of layout templates and page numbering
  • Editing the result tables with filter functions
  • List output in DOCX, RTF, XPS and PDF format
  • Export of tables in XSLX format- New plot output with selectable title and status legends- the freely created object views
  • Output of plots with standard views to scale and suitable plan paper size
  • Export functions for calculation and design results for ZEICON®, ALLPLAN, DICAD, ISBCAD as well as manufacturer software SchöckBole, HalfenHDB and FiligranFDB
iTWO structure fem Slab

The slab module of iTWO structure fem allows the calculation and design of simple and complex building construction slabs with integrated beams as reinforced concrete components. The graphic-interactive program environment allows the continuous input, calculation and design as well as evaluation and output of any slab system. The program application is easy to use and has an intuitive user interface. In addition to the functions of the basic module of iTWO structure fem, the following features are also included:

  • Straightforward menu navigation for all essential program functions
  • Simple 2D constructions for arbitrarily edged slab fields with recesses as well as walls and supports as elastic or fixed bearing
  • Reinforced concrete beams or covers as supporting beam components
  • Point, line and area loads on slab and beam fields or freely constructed
  • Direct definition of load areas and efficient generation of load diagrams for variable loads
  • 3D-View for the visualization of the plate geometry and load
  • Powerful FE solution with element formulation according to the Reissner-Mindlin-Theory
  • Automatic generation of the FE-system for arbitrarily thin and thick plates with high-quality triangular and square elements
  • Model-oriented beam generation with beam elements according to the Timoshenko theory including shear deformations
  • Possibility of processing tapered cross sections and the widths of underlays or covers
  • Modern element library, optionally with linear and square element approaches
  • Definition of component-independent attribute surfaces for material, cross-section and bedding
  • Simple definition of edge joints and bar joints with/without stiffness
  • Consideration of the elastic bedding with bedding failure due to compression or tension
  • Transfer of the loads from previous plate calculations
  • Determination of the orthotropic load-bearing behaviour of element and ribbed slabs as well as material or-thotropy
  • Powerful result evaluation for deformations, bearing forces, internal forces and design results
  • Load case by load case animation of the deformations for better control of the input data
  • Visualization of the results as isolines and surfaces as well as trajectories
  • Visualization of the results at line sections as diagrams
  • Output of component-oriented result diagrams and list outputs with graphics
  • Free configuration of the result output
  • List output with position and load plan and all component information
  • Results output for deformations, internal forces and as-values
  • Definition of any cutout window for the graphics in the output list
  • Online help and manual with introduction example
iTWO structure fem Limite State Design for Building Construction

Program component with Windows®-oriented working environment for ultimate limit state designs for beam, plate and shell structures according to DIN 1045-1, EN 1992-1-1 and corresponding NAs for DE, UK, CZ/SK, AT. The following checks are available for beam and shell structures:

  • Interactive graphical input of design parameters for ULS design
  • Verification control with automatic generation of the relevant design actions
  • Bending design for reinforced concrete
  • Shear force design and punching shear check for reinforced concrete
  • Concrete design for GRP reinforcement and high-strength reinforcing steel
  • Specification of shear joints, e.g. for filigree panels
  • Consideration of the widths and haunches involved in under- and overlay
  • Optional dimensioning at the gate of walls and columns
  • All design results can be calculated in a single operation on request
  • Display of results as contour lines and as numerical evaluation
  • Transfer of the design results to the results list with diagrams and graphics


The Following extensions exist for the Plate package Start:

iTWO structure fem extension

iTWO structure fem extension for free number of elements

The extension module of iTWO structure fem removes the limitation of the basic module for 100 beam and 1000 surface elements and allows a free element number for a unlimited application of the FE system.

iTWO structure fem SLS Proof for Concrete in Building Construction

Program component with Windows®-oriented working environment for serviceability limit state design for beam, plate and shell structures according to DIN 1045-1, EN 1992-1-1 and corresponding NAs for DE, UK, CZ/SK, AT. The following checks are available for beam and shell structures:

  • Interactive graphic input of design parameters for SLS design
  • Verification control with automatic generation of the relevant design actions
  • Determination of the minimum surface reinforcement
  • Determination of the robustness reinforcement
  • Minimum reinforcement for crack width limitation - Initial crack formation
  • Completed crack width check - simplified and as direct check
  • Limitation for concrete compressive stresses in cracked condition
  • Limitation for reinforcing steel stresses and prestressing steel stresses in cracked condition

*) available Q1/2021

iTWO structure fem Deformations in cracked state Concrete in building construction

Program component with Windows®-oriented working environment for the calculation of deformations in the cracked state of concrete for beam and shell structures according to DIN 1045-1, EN 1992-1-1 and corresponding NAs for DE, UK, CZ/SK, AT. The following services are available for combined beam and shell structures:

  • Interactive graphic input of the calculation parameters for the deformation checks
  • Consideration of the long-term behaviour for creep and shrinkage deformations
  • Automatic determination of the creep index and shrinkage from given characteristic values
  • User-specific specification of the creep index and shrinkage
  • Calculation of deformations in state II of the concrete for surface bearing structures predominantly loaded in bending
  • Consideration of the stiffness in the cracked state of beams or covers
  • Interactive graphical evaluation of the deformation results in the uncracked and cracked state

With the option Deformation analysis in the cracked state in building construction, the basic system iTWO structure fem can be extended for the processing of deformation analyses for combined panel and beam systems. The completely graphic-interactive processing allows a quick familiarization and has the following special features:

  • Clear input of the calculation and design parameters
  • Determination of the influences of creep, shrinkage and concrete damage according to Krüger/Mertsch
  • Consideration of cutting force redistributions in the system
  • Verified method for evaluating effects from the cracked state
  • Interactive graphical evaluations with comparison possibilities for deformations in cracked and non-cracked state
iTWO structure fem Plugin Analyse REVIT2FEM

The REVIT2FEM add-in provides the analysis model with the properties defined in Autodesk-Revit® for the material and cross-sectional characteristics, support conditions and loads for further processing or direct subsequent calculation and design. The analysis model can be transferred partially or fully automatically as a 3D system or as a 2D subsystem with consideration of the supporting components. The following functions are available for beam and shell structures:

  • Transfer of the analysis model as a complete system, as selected levels or as selected components
  • Assignment of material and cross-sectional characteristics between Autodesk-Revit® and iTWO structure fem
  • Completion of material and cross-section data and saving of the created mapping
  • Optional replacement of supports and walls under the ceiling with rigid or elastic bearing properties.
  • Optional replacement of walls and columns standing on the ceiling as load case related dead weight loads
  • Administration of model import directly into Autodesk-Revit® as a list of created analysis models
  • Rename or delete the files or open them with iTWO structure fem directly in Autodesk-Revit®
  • System- and project-related storage of the configuration for the model import

Cover Picture: RIB Software SE – shutterstock_344491979

iTWO structure fem Slab Package SCREENSHOTS


Contact sales structural engineering

+49 711 7873-157
[email protected]

Contact & Hotline

Solutions for structural engineering and test engineers

For questions on events

Support for structural engineering