Lines can be imported into RFEM either as lines or members. The names of layers are adopted as the cross-section names, and the first material from the predefined materials is assigned. However, if the section of the Dlubal cross-section library and the material are recognized from the layer name, they are adopted as well.
When importing DXF files as background layers, you have the option to select a reference point in the graphic preview.
Did you know? You can enter the soil layers that you have obtained from the subsoil expertises done in the locations into the program in the form of soil samples. Assign the explored soil materials, including their material properties, to the layers.
For the definition of the samples, you can enter the data in tables as well as in the respective editing dialog box. Furthermore, you can also specify the groundwater level in the soil samples.
Use the interfaces for more efficient work. You can import your structures in the DXF format as lines from Autodesk AutoCAD into RFEM 6 / RSTAB 9.
Furthermore, you can export different objects (for example, cross-sections) from RFEM 6 / RSTAB 9 to separate layers in Autodesk AutoCAD.
- Free definition of two reinforcement layers
- Design alternatives to avoid compression or shear reinforcement
- Design of surfaces as deep beams (theory of membranes)
- Option to define basic reinforcements for top and bottom reinforcement layers
- Free definition of provided surface reinforcement
- Result output in points of any selected grid
- Design with design moments at column edges
- Determination of deformation in state II; for example, according to EN 1992‑1‑1, 7.4.3, and ACI 318‑19 24.2.3, Table 24.2.3.5
- Considering tension stiffening
- Considering creep and shrinkage
- Fatigue design according to EN 1992‑1‑1, Chapter 6.8 (see this Product Feature)
- Design of a shear joint between the web and flange of ribs
- Optional pure slab or wall design of surfaces for a 2D model type
- Precise breakdown of reasons for failed design
- Design details of all design locations for better traceability of reinforcement determination
Entering soil layers for soil samples is performed in a clearly arranged dialog box. A corresponding graphical representation supports clarity and makes checking the input user-friendly.
An extensible database facilitates the selection of soil material properties. The Mohr-Coulomb model as well as a nonlinear model with stress and strain dependent stiffness are available for a realistic modeling of the soil material behavior.
You can define any number of soil samples and layers. The soil is generated from all entered samples using 3D solids. Assignment to the structure is carried out using coordinates.
The soil body is calculated according to the nonlinear iterative method. The calculated stresses and settlements are displayed graphically and in tables.
The meshing algorithm of RWIND Simulation uses the boundary layer option to mesh the area near the model surface with a voluminous layer mesh. The number of layers is controlled by a user-defined parameter.
This fine mesh in the area of the model surface helps to represent the wind velocity close to the surface.
The stiffness of gas given by the ideal gas law pV = nRT can be considered in the nonlinear dynamic analysis.
The calculation of gas is available for accelerograms and time diagrams for both the explicit analysis and the nonlinear implicit Newmark analysis. To determine the gas behavior correctly, at least two FE layers for gas solids should be defined.
After opening the module, the materials and surface thicknesses defined in RFEM are preset. The nodes to be designed are automatically recognized but can also be modified by the user.
It is possible to consider openings in the area with risk of punching shear. The openings can be transferred from RFEM or specified only in RF‑PUNCH Pro so they do not effect the stiffnesses of the RFEM model.
The parameters of the longitudinal reinforcement are the number and direction of the layers and the concrete cover, specified separately for the top and bottom of the slab on a surface-by-surface basis.
The next input window allows you to define all additional details for nodes of punching shear.
The module recognizes the position of the punching node and automatically sets, whether the node is located in the center of the slab, on the slab edge or in the slab corner.
In addition, it is possible to set punching load, load increment factor β, and the existing longitudinal reinforcement. Optionally, the minimum moments can be activated for determining the required longitudinal reinforcement and enlarged column head.
To facilitate orientation, a slab is always displayed with the corresponding node of punching shear. You can also open the design program by HALFEN, a German producer of shear rails. All RFEM data can be imported to this program for further easy and effective processing.
RF-CONCRETE Surfaces
The nonlinear calculation is activated by selecting the design method of the serviceability limit state. You can individually select the analyses to be performed as well as the stress-strain diagrams for concrete and reinforcing steel. The iteration process can be influenced by these control parameters: convergence accuracy, maximum number of iterations, arrangement of layers over cross-section depth, and damping factor.
You can set the limit values in the serviceability limit state individually for each surface or surface group. Allowable limit values are defined by the maximum deformation, the maximum stresses, or the maximum crack widths. The definition of the maximum deformation requires additional specification as to whether the non-deformed or the deformed system should be used for the design.
RF-CONCRETE Members
The nonlinear calculation can be applied to the ultimate and the serviceability limit state designs. In addition, you can specify the concrete tensile strength or the tension stiffening between the cracks. The iteration process can be influenced by these control parameters: convergence accuracy, maximum number of iterations, and damping factor.
- General stress analysis
- Graphical and numerical results of stresses and stress ratios fully integrated in RFEM
- Flexible design with different layer compositions
- High efficiency due to few entries required
- Flexibility due to detailed setting options for basis and extent of calculations
- A local overall stiffness matrix of the surface in RFEM is generated on the basis of the selected material model and the layers contained. The following material models are available:
- Orthotropic
- Isotropic
- User-defined
- Hybrid (for combinations of material models)
- Option to save frequently used layer structures in a database
- Determination of basic, shear, and equivalent stresses
- In addition to the basic stresses, the required stresses according to DIN EN 1995-1-1 and the interaction of those stresses are available as results.
- Stress analysis for structural surfaces including simple or complex shapes
- Equivalent stresses calculated according to different approaches:
- Shape modification hypothesis (von Mises)
- Shear stress hypothesis (Tresca)
- Normal stress hypothesis (Rankine)
- Principal strain hypothesis (Bach)
- Calculation of transversal shear stresses according to Mindlin or Kirchhoff, or user-defined specifications
- Serviceability limit state design by checking surface displacements
- User-defined specifications of limit deflections
- Possibility to consider layer coupling
- Detailed results of individual stress components and ratios in tables and graphics
- Results of stresses for each layer in the model
- Parts list of designed surfaces
- Possible coupling of layers entirely without shear
After opening the program, you can define the standard and method according to which the design is performed. The ultimate and serviceability limit states can be designed according to the linear and nonlinear calculation methods. Load cases, load combinations or result combinations are then assigned to different calculation types. In other input windows, you can define materials and cross‑sections. In addition, it is possible to assign parameters for creep and shrinkage. Creep and shrinkage coefficients are directly adjusted, depending on the age of the concrete.
Support geometry is determined by means of design‑relevant data such as support widths and types (direct, monolithic, end, or intermediate support) and redistribution of moments as well as shear force and moment reduction. CONCRETE recognizes the support types from the RSTAB model automatically.
A segmented window includes the specific reinforcement data such as diameters, the concrete cover and curtailment type of reinforcements, number of layers, cutting ability of links, and the anchorage type. In the case of the fire resistance design, it is necessary to define the fire resistance class, the fire‑related material properties, and the cross-section side exposed to fire. Members and sets of members can be summarized in special 'reinforcement groups', each with different design parameters.
You can adjust the limit value of the maximum crack width in the case of crack width analysis. The geometry of tapers is to be determined additionally for the reinforcement.
There are various tools such as the object snap, user‑defined input grids, and guidelines, that facilitate the graphical input of structural data. DXF files can be imported as line models or used as a layer in the background in order to use specific snap points.
There are various tools such as the object snap, user‑defined input grids, and guidelines, that facilitate the graphical input of structural data. DXF files can be imported as line models or used as a layer in the background in order to use specific snap points.
- Free definition of two or three reinforcement layers in the ultimate limit state
- Vectorial representation of the main stress directions of internal forces allowing optimal orientation adjustment of the third reinforcement layer to the actions
- Design alternatives to avoid compression or shear reinforcement
- Design of surfaces as deep beams (theory of membranes)
- Option to define basic reinforcements for top and bottom reinforcement layers
- Definition of designed reinforcement for serviceability limit state design
- Result output in points of any selected grid
- Optional extension of the module with nonlinear deformation analysis. The calculation is performed in RF‑CONCRETE Deflect by reducing the stiffness according to the standard, or in RF‑CONCRETE NL by the general nonlinear calculation determining the stiffness reduction in an iterative process.
- Design with design moments at column edges
- Precise breakdown of reasons for failed design
- Design details of all design locations for better traceability of reinforcement determination
- Export of isolines for the longitudinal reinforcement in a DXF file for further use in CAD programs as a basis for reinforcement drawings
RF-CONCRETE Surfaces:
The nonlinear deformation analysis is performed by an iterative process considering the stiffness in cracked and non-cracked sections. The nonlinear reinforced concrete modeling requires definition of material properties varying across the surface thickness. Therefore, a finite element is divided into a certain number of steel and concrete layers in order to determine the cross-section depth.
The mean steel strengths used in the calculation are based on the 'Probabilistic Model Code' published by the JCSS technical committee. It is up to the user whether the steel strength is applied up to the ultimate tensile strength (increasing branch in the plastic area). Regarding material properties, it is possible to control the stress-strain diagram of the compressive and tensile strength. For the concrete compressive strength, you can select a parabolic or a parabolic-rectangular stress-strain diagram. On the tension side of the concrete, it is possible to deactivate the tensile strength as well as to apply a linear-elastic diagram, a diagram according to the CEB-FIB model code 90:1993, and concrete residual tensile strength considering the tension stiffening between the cracks.
Furthermore, you can specify which result values should be displayed after the nonlinear calculation at the serviceability limit state:
- Deformations (global, local based on non-/deformed system)
- Crack widths, depths, and spacing of the top and bottom sides in principal directions I and II
- Stresses of the concrete (stress and strain in principal direction I and II) and of the reinforcement (strain, area, profile, cover, and direction in each reinforcement direction)
RF-CONCRETE Members:
The nonlinear deformation analysis of beam structures is performed by an iterative process considering the stiffness in cracked and non-cracked sections. The material properties of concrete and reinforcing steel used in the nonlinear calculation are selected according to a limit state. The contribution of the concrete tensile strength between the cracks (tension stiffening) can be applied either by means of a modified stress-strain diagram of the reinforcing steel, or by applying a residual concrete tensile strength.
The global calculation assigns the stiffness determined by means of the selected composition and the glass geometry to each surface. Then, the calculation proceeds using the plate theory. It is possible to select whether the shear coupling of layers should be considered.
In the case of the local calculation, you can further specify 2D or 3D calculation. Two-dimensional calculation means that the single-layer or laminated glass is modeled as a surface, whose thickness is calculated on the basis of the selected structure and glass geometry (using the plate theory). Similarly to the global calculation, you can optionally consider shear coupling of layers.
The 3D calculation uses solids in the model to substitute each composition layer. This way, the results are more accurate, but the calculation may take more time.
It is possible to model insulating glass only if local calculation is selected. The gas layer is always modeled as a solid element, so it is necessary to design individual insulating glass parts independently of the surrounding structure. The ideal gas law (thermal equation of state of ideal gases) is considered for the calculation and the third-order analysis.
In the add-on module, select the surfaces to be designed (for example, by using the Select function). The geometry of the glass pane, as well as the loads, is imported from the RFEM model.
Then, you have to decide if the calculation should be performed without the influence of the surrounding structure (local calculation) or with consideration of this influence (global calculation). If you select the local calculation, each surface selected for the design is detached from the model and calculated separately.
The global calculation considers the entire structure, including entered glass panes. All glass composition data and glass properties of individual layers are to be defined in RF-GLASS input windows. You can select layers of type glass, foil, and gas. The desired material can be imported directly from the library, which contains a large number of materials.
All parameters of individual layers, including their thicknesses, are editable. In addition, you can create a number of compositions in RF-GLASS, allowing you to design different types of glass together.
For insulating glass, you can consider external loads as well as loads due to temperature, atmospheric pressure, and altitude changes for the analysis. The module calculates these loads automatically on the basis of climatic load parameters. If you select the local calculation type, it is necessary to define line supports, nodal supports, and boundary members of the surfaces in RF-GLASS. These supports and members are considered in RF-GLASS only and have no influence on the model created in RFEM.
- Design of single-layer or laminated glass as well as gas layer insulating glass
- design of curved glass
- Option to select either local calculation without regard to the influence of a surrounding structure, or global calculation with regard to the influence of an entire structure
- Calculation of limit stresses according to DIN 18008:2010-12 or TRLV:2006-08
- Assignment of loads to load duration classes
- Extensive material library including all common glass, foil, and gas types in compliance with the DIN 18008:2010-12, E DIN EN 13474 standards, and the TRLV:2006-08 regulation
- Optional consideration of shear coupling of layers
- Consideration of climatic loads
- Calculation according to the linear static analysis or nonlinear analysis according to the large deformation analysis. analysis
- Stress analysis, ultimate limit state design, serviceability limit state design
- Graphical representation of all results in RFEM
- Possibility to filter results and color scales in result tables
- Direct data export to MS Excel
It is necessary to select load cases, load combinations, and result combinations for the ultimate and the serviceability limit state design. After selecting the surfaces to be designed, you can define the relevant material model.
The structure of layers forming the basis for the stiffness calculation can vary. You can adjust the parameters defined by the selected material model according to your individual needs. The 3*3 matrix of the layers is modifiable as well. In this way completely free selection when generating the stiffnesses is provided.
The limit stresses of each layer are defined by the selected material. These values can be customized as well.
The definition of soil layers is performed in a clearly arranged input window. An extensible library facilitates the selection of soil properties.
The elasticity can be defined either by the stiffness modulus or the modulus of elasticity and the Poisson's ratio. It is possible to define any number of soil layers. You can assign the layers to the building graphically or by entering the relevant coordinates.
In order to facilitate the data input, surfaces, members, sets of members, materials, surface thicknesses, and cross-sections are preset in RFEM. It is possible to select the elements graphically using the [Select] function. The program provides access to the global material and section libraries. Load cases, load combinations, and result combinations can be combined in various design cases. You can enter all geometric and standard-specific reinforcement settings for the reinforced concrete design in a segmented window. The geometry entries in both RF‑CONCRETE modules differ from each other.
- In the RF-CONCRETE Members add-on module, for example, This includes, for example, specifications for the curtailment of rebars, number of layers, cutting ability of links, and anchorage type. For the fire resistance design of reinforced concrete members, you have to define the fire resistance class, the fire‑related material properties, and the cross‑section sides exposed to fire.
- In the RF‑CONCRETE Surfaces add‑on module, it is necessary to specify, for example, the concrete cover, the reinforcement direction, the minimum and the maximum reinforcement, the basic reinforcement to be applied, or the designed longitudinal reinforcement, as well as the rebar diameter.
Surfaces or members can be summarized in special "reinforcement groups", each defined by different design parameters. This way, it is possible to efficiently calculate alternative designs with different boundary conditions or modified cross‑sections.