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Frequently Asked Questions (FAQ)
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AnswerBoth RFEM and RSTAB provide a suitable solution. In addition to Eurocode 2, the international standards, such as ACI 318, CSA A23.3, SIA 262, or GB 50010, are also available for the design in both programs.
With the add-on modules for designing columns or foundations, or for punching shear designs, it is possible to quickly and reliably calculate the structural components.
Main Programs RFEM or RSTABThe main programs RFEM or RSTAB are used to define structures, materials, and actions.
For reinforced concrete structures, RFEM is clearly the first choice as it allows you to also create structural systems consisting of plates, walls and shells in addition to spatial frame structures. RFEM is the more diverse variant as it can be equipped and extended with the corresponding add-on 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 the 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 it is necessary to perform seismic analysis or vibration designs of a building, the RF‑/DYNAM Pro add-on modules provide special tools for determining natural frequencies and mode shapes, for an analysis of forced vibrations, a generation of equivalent loads, or for a nonlinear time history analysis.If you have any question about the Dlubal Software programs, please do not hesitate to contact the sales department.
AnswerNo, this is unfortunately not possible.If the "Tension Stiffening" option is not applied for the calculation, the damage parameter ζ is either "0" for "uncracked sections" or "1" for "cracked sections." For this, see the technical article about the distribution of the damage parameter ζ under Downloads below.Nevertheless, the manual specification of ζ = 0.5, for example, is not possible.
AnswerThe concrete tensile strength fct, eff, wk = fctm × crack width factor is applied.
AnswerNo, it is unfortunately not possible.
AnswerIn this case, the Calculation Method and the type of the 2D model are important.When using the analytical method (RF‑CONCRETE Deflect), it is possible to perform the calculation in 2D models. When using the nonlinear method (RF‑CONCRETE NL), the calculation for 2D XY (uZ/φX/φY) is not possible. In the nonlinear calculation, shrinkage is represented internally as strain load, which is not possible in this type of 2D model due to the limited degrees of freedom.Convert 2D to 3D ModelIn General Data, you can simply convert a 2D model into a 3D model. For the supports, all degrees of freedom not contained in the 2D model are fixed when converting to a 3D model (see the video).
AnswerThe differences resulting from the determination of the deformation in the cracked state can have various causes. In the case of deviations, you should check the following points:
Is the same calculation method applied?
RF-CONCRETE Deflect uses the analytical analysis approach according to EN 1992‑1‑1, 7.4.3.RF-CONCRETE NL uses the physically nonlinear analysis approach.You can find more information about the calculation methods in Chapter 2.7 and Chapter 2.8 of the RF‑CONCRETE Surfaces manual.
Is the same initial structure available?
If considering the underlying structural system as equivalent, the results of the linear calculation can be considered in the best way. The linearly determined deformation of the underlying combination should be approximately equal. Possible differences in the linear deformation may be increased in the cracked state in connection with the deformation analysis.
Are the same effects taken into account?
When comparing, make sure that the same effects, such as creeping and shrinkage, are taken into account (Figure 02).
Are the same initial values available?
In connection with the deformation analysis, you should further check if the same initial values are available. In this case, a special attention has to be paid to the fact whether the applied reinforcement (Figure 03) and the lever arm or the concrete cover are the same.
If you cannot find the cause after the fundamental examination, please contact our hotline.
When using the automatic arrangement of the reinforcement, make sure that the additional reinforcement is applied, if necessary, for the serviceability limit state designs in addition to the basic reinforcement. The default setting in the add-on module is selected in such a way that the required reinforcement from the ultimate limit state is also applied for the SLS.
You can select the reinforcement that is applied for the SLS in "Additional Reinforcement for Serviceability State Design." The Info button explains the individual options (Figure 02).
The reinforcement applied to the designs can be followed by using the "Selected Reinforcement for SLS Check" function (Figure 03).
The RF-CONCRETE Deflect add-on module is a module extension of RF‑CONCRETE Surfaces.The calculation of deformations in cracked sections (state II) with RF‑CONCRETE Deflect can be activated by selecting the "Analytical method of check" in the "Serviceability Limit State" tab in RF‑CONCRETE Surfaces.In the detail settings, you can activate the "Deflection with RF‑CONCRETE Deflect" option.The results from the calculation with RF‑CONCRETE Deflect are then available for the respective design case in the "Serviceability Limit State" tab of the Results navigator.
AnswerYes, the exponent n is applied differently. Design details can help you to understand this. For EN 1992‑1‑1, for example, n=2 is applied (see Figure 01), and for CSA A23.3-14, n=3 is applied (see Figure 02).
AnswerThe crack depth is used to specify the height of the cross-section referring to damage, or, in other words, to a stiffness modification. The nonlinear calculation and the associated layer arrangement of the FE element (see Figure 02) is the basis for the results of this value.
The results of the crack depth are displayed by side and in both principal directions of the cracks. The direction is also able to relate to the trajectories ϕ,hw.
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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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