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Frequently Asked Questions (FAQ)
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The RF‑CONCRETE Columns add-on module allows you to define a "creep-producing permanent load." You can find the corresponding tab in Window "1.1 General Data."
The reason for the entry is that RF‑CONCRETE Columns can apply this "creep-producing permanent load" for the automatic determination of the effective creep ratio according to EN 1992‑1‑1, 5.8.4.
In contrast, there is no explicit input option for this creep-producing permanent load in RF‑CONCRETE Members. In RF‑CONCRETE Members, the stability analysis of reinforced concrete columns by means of nonlinear design does not automatically reduce the effective creep ratio. You can find the background to the effective creep ratio applied in RF‑CONCRETE Members in Chapter 2.4.6 of the RF-CONCRETE Members manual.
The same applies to the CONCRETE Columns or CONCRETE add-on modules for RSTAB.
In the case of cross-section design, RF‑CONCRETE Members or CONCRETE uses in the calculation the stress-strain diagram for reinforcing steel according to DIN EN 1992‑1‑1, 3.2.7(2)a, that is, the increasing upper part up to ftk and the strain limitation of εud = 0.025.
In RF‑CONCRETE Members or CONCRETE, there is no option to switch to the design with the horizontal part according to 3.2.7(2)b.
However, you can possibly use a user-defined material with ftk = fyk.
After the calculation, you can switch to the result window "2.4 Required Reinforcement by x‑Location" in the RF‑CONCRETE Members (RFEM) or CONCRETE (RSTAB) add-on module.
Here, you can select a certain result row for a particular design and x-location (upper table in Window 2.4). Then, you can evaluate the intermediate results in the lower table in Window 2.4. This covers the "Neutral Axis Depth x", for example. The location of the neutral axis for the selected design location is displayed in the graphic on the right of Window 2.4 .
Furthermore, you can display the distribution of the neutral axis depth along the member length graphically in the model or in "Result Diagrams on Member."
You can find the setting in Window 1.5 Support.
Here, you can enter the support width and type, and specify whether to carry out the moment redistribution, or the reduction of moments or shear forces.
Depending on the standard selected in Window 1.1, there are different options available. The option applies to RF‑CONCRETE Members (RFEM 5) and CONCRETE (RSTAB 8).
If the calculation of the longitudinal reinforcement according to the standard is activated, the required reinforcement content is taken into account when displaying the required reinforcement.See the following graphic with the distribution of the required reinforcement without the minimum longitudinal reinforcement according to the standard:Figure 01 - Distribution of Required Reinforcement Without Minimum Longitudinal Reinforcement According to StandardAnd in comparison, the distribution of As,erf,-z(top) with the minimum longitudinal reinforcement according to the standard:Figure 02 - Distribution of Required Reinforcement Incl. Minimum Longitudinal Reinforcement According to StandardIn the result window '2.4 Required Reinforcement by x-Location', you can see which reinforcement is required at each x-location of the designed member. If the minimum longitudinal reinforcement according to the standard becomes relevant, this is indicated by the message No. 26) or 27).At locations where the minimum longitudinal reinforcement is not critical, only the statically required longitudinal reinforcement is displayed. Messages No. 26) and 27) are missing in this case.
AnswerYes, for the nonlinear calculation in RF-CONCRETE Members, it is possible to select the high-strength steel SAS 670 for the design. In this way, you can perform stability analysis for columns, among other things.The steel can be selected in the Materials section of the module (see Figure 01). Since DIN EN 1992-1-1 only allows fyk = 500 N/mm² by default, this limit must be adjusted when using SAS 670.In the general data, you can create a user-defined National Annex where the maximum value of yield strength is increased to fyk ≥ 670 N/mm² in Point 3.2 (see Figure 02).
Please select only members with a reinforced concrete cross-section in the input dialog box 1.6 for the design. If selecting members made of steel (e.g.), you will get the corresponding error message.Figure 01 - Message No. 2379 - Invalid Material DataIn case you select 'All Members', the members with a steel reinforcement area are automatically removed from the design.
AnswerYou will find an option in the "Settings" of the add-on module (see picture 01).
AnswerBoth RFEM and RSTAB are available as solutions. In addition to Eurocode 2, international standards such as ACI 318, CSA A23.3, SIA 262 or GB 50010 are also available for the designing in both programs.
With additional modules for columns, foundations, or punching shear designs, it is possible to calculate the components quickly and reliably.
Main Programs RFEM or RSTABThe main programs RFEM or RSTAB are used to define structures, materials, and Actions.
RFEM is clearly the first choice for solid structures, since in addition to the possibility of creating spatial frame structures, structural systems consisting of plates, walls and shells can be created as well. RFEM is the more diverse variant, as it can be equipped and extended with appropriate additional modules for all materials and designs.
- Eurocode 2 (EN 1992-1-1)
- SIA 262
- ACI 318
- CSA A23.3
- GB 50010
- RF-/CONCRETE Columns
Reinforced concrete design according to the model column method or nominal curvature method
- RF-PUNCH Pro
Punching Shear Designs of Surfaces
- RF-/FOUNDATION Pro
Design of Single, Bucket and Block Foundations
- RF-CONCRETE Deflect (RFEM)
Analytical deformation analysis
- RF-CONCRETE NL
Realistic deformation analysis of surfaces and members
Dynamic AnalysisIf earthquake calculations or vibration analysis of the building are necessary, the RF-/DYNAM Pro Add-on Modules provide suitable tools for determining natural frequencies and shapes, forced vibration analysis, generation of equivalent loads or also for nonlinear time history analysis.If you have any further questions on the Dlubal programs, please do not hesitate to contact the sales department.
AnswerThis may be related to the curtailment of the provided reinforcement.If no curtailment is activated, a uniform reinforcement is designed across the entire structure (Figure 01).
The curtailment of the reinforcement can be activated in the "Longitudinal Reinforcement" tab of the add-on module (Figure 02).
After activating the curtailment, it is possible to define a number of zones. The higher the number of zones is, the more precisely the provided reinforcement can follow the distribution of the required reinforcement (Figure 03).
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Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
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