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Answer
The sum indicated in this table does not reflect the correct superposition according to the standard. This is a simple summing up of the equivalent loads. A superposition with the selected superposition rule (SRSS or CQC) is not performed in this table!Furthermore, there are differences if activating the accidental torsion in the addon module. This leads to the generation of two load cases for each mode shape. They always contain the torsional moment in the positive and in the negative direction. As a result, the equivalent loads are doubled in this table. 
Answer
First, the ribbed plate should not be modeled with the classic rib member from RFEM, but with an eccentric beam member that is arranged on the bottom surface of the actual plate. Rib members cannot be calculated with RFCONCRETE NL with regard to deformations.
The eccentric beam is then designed in RF‑CONCRETE Members. In the "Serviceability Limit State" tab of Window 1.1, you can activate the "Nonlinear calculation.". In the detailed settings for the nonlinear calculation, you can activate the export of stiffness from the nonlinear calculation.
Figure 01  Detail Settings for Nonlinear Calculation of SLS in RFCONCRETE Members
In the example presented here, the stiffness is exported "individually" for each LC calculated in RF‑CONCRETE Members. You can find more information about the options "Individual" and "Consistent for reference load" under the link below.
After the calculation in RF‑CONCRETE Members, the exported stiffnesses of the calculated COs are available in RFEM, where you can activate them in the respective COs for a new calculation of internal forces. To do this, activate the extra options of the respective CO. In the "Extra Options" tab, you can then activate the stiffness exported from the RF‑CONCRETE Members addon module for a new determination of internal forces.
Figure 02  Extra Options in Calculation Parameters of Load Combinations in RFEM
After recalculating the internal forces of the COs in RFEM (taking into account the exported stiffness from RF‑CONCRETE Members), you can apply them for design in RF‑CONCRETE Surfaces.
The following figure shows the deformations of the ribbed plate in RF‑CONCRETE Surfaces, taking into account the stiffness in cracked state from the design in RF‑CONCRETE Members.
In comparison to Figure 03, the linearelastic stiffness in uncracked state (state I) was applied in Figure 04 for the eccentric beam.
Figure 04  Deformations from RFCONCRETE Surfaces Without Stiffness from RFCONCRETE Members
Notes on the procedure described above:
 In this case, the calculation was performed in RF‑CONCRETE Members first, and the resulting stiffness was exported. This approach was selected because it was assumed that the eccentric rectangular crosssection will proceed to the cracked state (state II) first.
 The procedure shown "only" describes one iteration and is therefore only an "approximation" since an uncracked plate was assumed for the calculation of the eccentric rectangular crosssection.
 The shrinkage effect is applied as an external load in the NL calculation in RF‑CONCRETE Members. This means that, for example, an unsymmetric reinforcement would result in an additional curvature, even if the crosssection remained in the uncracked state. When calculating the plate in RF‑CONCRETE Surfaces, this effect of shrinkage on the member crosssection is not taken into account anymore.

Answer
To run the software license, the authorization file AUTHOR.INI is required, which contains the product key information. If there is no valid license found when starting the program for the first time, the Authorization dialog box appears.Select the Use full version option and click the [OK] button. A Windows dialog box appears, where you set the path to the AUTHOR.INI file and confirm by clicking the [Open] button. Make sure that you are connected to the Internet.As soon as the authorization is loaded successfully, the following message is displayed: Authorization completed successfully. 
Answer
The fully plastic section modulus Z_{full} is related to the fullplastic bending moment M_{pl,full}. For M_{pl,full}, there is only one internal force available in the respective direction. It is not possible to increase this internal force, even if the crosssection is not perfectly plastic.
On the other hand, the maximum plastic bending moment M_{pl,max} related to the maximum plastic section modulus Z_{max} refers to the perfectly plastic state of the crosssection. In this case, the interaction of the internal forces in the y and zdirection is possible.

Answer
The fully plastic section modulus Z_{full} is related to the fullplastic bending moment M_{pl,full}. For M_{pl,full}, there is only one internal force available in the respective direction. It is not possible to increase this internal force, even if the crosssection is not perfectly plastic.
On the other hand, the maximum plastic bending moment M_{pl,max} related to the maximum plastic section modulus Z_{max} refers to the perfectly plastic state of the crosssection. In this case, the interaction of the internal forces in the y and zdirection is possible.

Answer
Yes, this is possible by using RFEM and the addon modules RF‑CONCRETE Members and RF‑CONCRETE NL. For RSTAB, the CONCRETE addon module is required.
In the design modules of RFEM or RSTAB, you can define "Provided Basic Reinforcement" and perform a nonlinear calculation in the ultimate limit state for this reinforcement.
As a result, you obtain the utilization ratio from the nonlinear calculation assuming the provided longitudinal reinforcement.
Note:
The nonlinear calculation is already included in the CONCRETE addon module for RSTAB. In RFEM, the RF‑CONCRETE NL addon module is required. 
Answer
In the case of using timber materials in RFEM, a message appears when creating the material, saying that the "isotropic linear elastic" material model is only correct for the calculation with members because the Poisson's ratio is very large. For surfaces, it is necessary to select a different material model.
Figure 02  Material Definition for Timber
If you have assigned the material with the orthotropic material model to the surface, it is not possible to use certain orthotropy types. This material cannot be used for ribbed plates.
Figure 03  Stiffness Parameters  Orthotropic Elastic Material Model
However, if you have assigned the material to the surface with an isotropic linear elastic material model, you can access all types of orthotropy.
Figure 04  Stiffness Parameters  Isotropic Linear Elastic Material Model
When entering the geometry for the ribbed plate, Error No. 30343 appears due to the incorrectly assigned timber material for the surface: "The computed stiffness matrix is not positive definite."

Answer
The axis orientation of the surfaces in your model is probably not adjusted. For a circular surface, it is recommended to specify the orientation of the axes for surfaces or the axes for results of the surfaces.You can adjust the axes for each surface. In the "Axes" tab, you can find the subtabs "Axes for Input" and "Axes for Results."The "Axes for Results" tab adjusts the axes of the surface for the results. Here you can specify the orientation of the axes using a point, for example. A great advantage of this method is that the results are not deleted when adjusting the axes.The "Axes for Input" tab adjusts the axes of the surface for the orientation and results. Here you can specify the orientation of the axes on a line, for example.The results of both axis adjustments are the same. For symmetric loading, the expected symmetric results are provided. 
Answer
The temperature loads as surface loads on general glass crosssections cannot be considered by modeling them as solid elements in the program. With the default settings, the glass pane is modeled by using 3D solid elements.
Figure 02  Default Setting for Modeling Laminated Glass
However, the 2D calculation allows for modeling temperature loads as surface loads. You can set this in the details of the layer structure, so that the 2D calculation (plate theory) is performed. In this case, it is also possible to consider the shear coupling between the layers, if necessary.
Figure 03  Layer Structure 1: 2D Without Considering Shear Coupling
Further details on calculating and using laminated glass can be found in the technical article "Calculation and Use of Laminated Glass."
After the successful calculation, you obtain the results for the respective layer structure. Figure 04 shows the results as an example of a layer structure without shear coupling.
Figure 04  Layer Structure 1: Results Without Considering Shear Coupling

Answer
The inaccuracy is caused by the fact that RFEM calculates the area of the circle approximately by dividing the boundary, that is, as a polygon. In this case, the result is 3.1214447 kN instead of 31.416 kN. On the other hand, the length of the boundary curve is calculated exactly as a circle.If you need a graphically accurate number (that is, an image for the structural analysis), this can be solved by reducing the number of decimal places displayed.
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First Steps
We provide hints and tips to help you get started with the main programs RFEM and RSTAB.
Wind Simulation & Wind Load Generation
With the standalone 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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