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Frequently Asked Questions (FAQ)
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AnswerAs a general solution, RFEM and RSTAB are the ideal solution . In addition to the Eurocode 2 , international standards such as ACI 318 , CSA A23.3, SIA 262 or GB 50010 are available for the design for both programs.
With add-on modules for columns, foundations, or punching designs, you can design structural components quickly and safely.
Basic programs RFEM or RSTABWith the basic programs RFEM or RSTAB structures, materials, and which are impact defined.
For solid construction, RFEM is clearly the first choice , because in addition to the possibility to create spatial frameworks, plates, disk and shell structures can be additionally processed. RFEM is the more versatile option because 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 or nominal curvature method
- RF-PUNCH Pro
Punching Shear Design of Surfaces
- RF-/CONCRETE FOUNDATION Pro
Dimensioning of single, quiver and block foundations
- RF-CONCRETE Deflect (RFEM)
Analytical deformation analysis
- RF-CONCRETE NL
Realistic deformation analysis on surfaces and members
Dynamic AnalysisIf earthquake calculations or vibration analyzes are necessary for the building, the RF-/DYNAM Pro add-on modules provide suitable tools for determining natural frequencies and shapes, analysis of forced vibrations, generation of equivalent loads, or for the nonlinear time history analysis.If you have any questions about the Dlubal software, contact the sales department
AnswerThe graphic display of the nodal displacements and rotations is made via the entry GlobalControlling deformations in the Results navigator. Additionally, there is a possibility to display the deformations not only as lines but also as colored cross-sections in the Project Navigator.
AnswerThe internal forces and deformations are determined according to the second-order analysis for flexural-torsional buckling taking into account 7 degrees of freedom. For a linear calculation of deformations, a vertical/horizontal load results in only one vertical/horizontal deformation. Since the internal forces refer to the deformed system and it is a nonlinear analysis, this is not valid for the second-order analysis for flexural-torsional buckling.
The deformations in the shear center can be checked in RSTAB and RFEM with the RF-/FE-LTB add-on module (see Figure 02). The deformations that additionally result from the displacements or rotations can only be controlled with a surface model in RFEM.
AnswerNo, this is unfortunately not possible.If the option 'Tension Stiffening' is not applied for the calculation, the distribution coefficient ζ is either '0' for 'uncracked' or '1' for 'cracked'. See also the technical article for the distribution of the distribution coefficient ζ linked below.But the manual specification of e.g. ζ = 0.5 is not possible.
AnswerIt is being applied the concrete tensile strength fct, eff, wk = fctm x crack width factor.
AnswerNo, this is unfortunately not possible.
AnswerDeformation of members are displayed as single colored lines per default. Please let them displayed as colored cross-sections. Therefore, it is always a good idea to decrease the Display factor by the deformation to 1.0, otherwise, the results might be misinterpreted.
The definition of slippage is recommended here. To do this, you have to set the partial effect in the 'Non-linearity' edit dialog box of the 'Edit Nodal Support' dialog box. In the 'Non-linearity - Partial Effect' dialog box, it is now possible to define a slippage in the respective area. The adjoining diagram is used for the check, see Figure 1.
First, please note that the local deformations of surfaces are always related to the undeformed system. Therefore, for a multi-storey building, the deformations of the top floor also include the deformations of the lower floors, as shown in Figure 01 on the left.
Figure 01 on the right shows the corresponding bending moment m-y. It is identical for the floors, as expected for this simple model. In such a case, the partial calculation of the individual floors is no problem, because the relative deformation seems to be identical for each floor.
However, it becomes problematic if the supporting elements are loaded differently or if the stiffness of the supporting elements within a floor is different. Figure 02 shows the bending moment m-y of such a system. It is apparent that the distribution, especially between the bottom floor and the top floor, shows the greatest differences. In this particular case, internal columns with less stiff cross-section were added in addition to the corner columns. For this reason, the relative deformation increases more with each additional floor in the middle than at the corner columns.
In reality, this structure will not exist in this way because the floors are manufactured one after the other and thus the deformations (for example due to self-weight) are compensated from one floor to another. Thus, it is a typical structural state problem. The question arises, therefore, of whether the effects can be neglected or if, for example, it is necessary to analyze the results with the add-on module RF-STAGES.
AnswerDifferences resulting from the determination of the deformation in the cracked state can have different causes. The following points should be checked for deviations:
Is the same calculation method applied?
RF-CONCRETE Deflect uses an analytical analysis approach according to EN 1992-1-1 7.4.3.RF-CONCRETE NL uses a physically nonlinear analysis approach.More detailed information about the calculation methods can be found, for example, in the RF-CONCRETE Surfaces Guide in Chapter 2.7 and 2.8.
Is the same initial structure available?
The results of the linear calculation provide the best tool for consideration if the underlying system should be taken for equivalent. The linearly determined deformation of the underlying combination should be approximately equal. Any 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 performing a comparison, make sure that the same effects as for example creep and shrinkage are taken into account (Figure 02).
Are the same input values available?
Furthermore, it should be checked in connection with the deformation analysis if the same input values are available. In this case, it is necessary to pay particular attention to whether the applied reinforcement (Figure 03) and the lever arm or concrete cover are the same.
If not having found the cause after the fundamental examination, please contact our hot line.
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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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