In addition to our technical support (e.g. via chat), you’ll find resources on our website that may help you with your design using Dlubal Software.
Frequently Asked Questions (FAQ)
Search FAQ
Further Information
Customer Support 24/7

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
According to DIN EN 1993‑1‑1, 6.3.2.3 (2), the reduction factor χ_{LT} can be modified by the f factor for χ_{LT,mod}. You can activate or deactivate this option under National Annex Settings.

Answer
In addition to the stability analysis in Sections 6.3.1 to Section 6.3.3 of EN 1993‑1‑1 (Equivalent Member Method), RF‑/STEEL EC3 also provides the General Method according to Section 6.3.4 of EN 1993‑1‑1.This can be extended with the following options:~ The European lateraltorsional buckling curve, which is regulated in the German National Annex to EN 1993, for example.~ Extension of biaxial bending according to the dissertation by Dr. Naumes.~ The interpolation between lateral buckling and lateraltorsional buckling.When designing sets of members according to the General Method, a window is available in the Window "1.7 Nodal Supports  Sets of Members" where the nodal supports are displayed graphically on the set of members. In this way, the General Method represents a useful supplement to the other design methods, which has proven itself, particularly when designing tapers. It is not necessary to enter effective lengths in this method.In the "Details" of the addon module, you can select the method to be used for sets of members in the "Stability" tab (see Figure 01).The equivalent member method may only be used for straight sets of members with a uniform crosssection (that is, not for tapered joints). For members with a variable crosssection, use the preset General Method. 
Answer
Beam steering is the angular rotation of antennas under the effect of the present loads (wind, overload, earthquake, deformation, and so on). As an indication, for the GSM, the value of the beam steering must not exceed 1°. This limit of beam steering is often accessible in the clauses of the Technical Specifications of the project.
In RF‑/TOWER Design, it is possible to control the beam steering of antennas for the SLS design. To activate this rotation design of antennas, go to Details → Serviceability.
Figure 01  Option for Rotation Design of Antennas
As soon as you select this check box, the antennas are available in Window 1.10.2 Serviceability of Antennas. Here, you can enter the angular rotation limit of each antenna.
Figure 02  Window 1.10.2  Serviceability of Antennas
After the calculation, the maximum ratio is displayed in Window 2.7 Design by Antenna.
Figure 03  Window 2.7 Design by Antenna 
Answer
If the crosssection consists of several unconnected partial sections, the sum of the moments of inertia is calculated without the parallel axis theorem components. The crosssection shown in Figure 01 consists of two angle sections that are not connected to each other.
Figure 01  CrossSection Consisting of Several Unconnected Partial Sections
The individual angle sections have the following moments of inertia:
I_{y,1,2} = 180.39 cm^{4} (referred to the centroidal axes y, z)
I_{z,1,2} = 65.05 cm^{4} (referred to the centroidal axes y, z)
The moments of inertia of the entire crosssection result in:
I_{y,1+2} = 2 ⋅ I_{y,1,2} = 2 ⋅ 180.39 = 360.78 cm^{4} (referred to the centroidal axes y, z)
I_{z,1+2} = 2 ⋅ I_{z,1,2} = 2 ⋅ 65.05 = 130.11 cm^{4} (referred to the centroidal axes y, z)
If the crosssection consists of several connected partial sections, the sum of the moments of inertia is calculated with the parallel axis theorem components. The crosssection shown in Figure 02 consists of two connected angle sections.
Figure 02  CrossSection Consisting of Several Connected Partial Sections
The individual angle sections have the following crosssection properties:
A_{1,2} = 16.25 cm²
y_{S,0,1,2} = ±2.30 cm (referred to the zero point)
z_{S,0,1,2} = 3.07 cm (referred to the zero point)
I_{y,1,2} = 180.39 cm^{4} (referred to the centroid axes y, z)
I_{z,1,2} = 65.05 cm^{4} (referred to the centroid axes y, z)
The crosssection properties of the entire crosssection result in:
y_{S,0,1+2} = 0.00 cm (referred to the zero point)
z_{S,0,1+2} = 3.07 cm (referred to the zero point)
I_{y,1+2} = 2 ⋅ I_{y,1,2} + 2 ⋅ A_{1,2} ⋅ (z_{S,0,1,2}  z_{S,0,1+2})²
I_{y,1+2} = 2 ⋅ 180.39 + 2 ⋅ 16.25 ⋅ (3.07  3.07)² = 360.78 cm^{4} (referred to the centroidal axes y, z)
I_{z,1+2} = 2 ⋅ I_{z,1,2} + 2 ⋅ A_{1,2} ⋅ (y_{S,0,1,2}  y_{S,0,1+2})²
I_{z,1+2} = 2 ⋅ 65.05 + 2 ⋅ 16.25 ⋅ (2.30  0.00)² = 301.46 cm^{4} (referred to the centroidal axes y, z)

Answer
The design points in CRANEWAY have been adopted in compliance with the standard. In this case, the stresses are calculated for the following locations: Design Point 0
A periphery of the flange at the web edge or at the fillet start  Design Point 1
A flange at load application point (this can be checked as wheel spacing in Window 1.4)  Design Point 2
The flange edge
These points are not displayed in the resulting crosssection graphic in the CRANEWAY program. However, there is always a stress point at the design points 0 and 2 for which the result values can be directly displayed.  Design Point 0

Answer
RF/STEEL ColdFormed Sections is a module extension of RF‑/STEEL EC3. The only thing you need to do is to activate the design for coldformed crosssections in the detailed settings of RF‑/STEEL EC3 (Figure 01).
Figure 01  Activating Module Extension RF/STEEL ColdFormed Sections

Answer
Common coldformed crosssections can be modeled in SHAPE‑THIN. In General Data, select the "c/t parts and effective crosssection properties" check box (Figure 01).
Then, select the "EN 1993‑1‑3 (Cold formed crosssection)" option in the "c/tParts and Effective CrossSection" tab of the Calculation Parameters dialog box (Figure 02).
You can optionally check the geometric conditions for the applicability of the standard specified in EN 1993‑1‑3 [1], 5.2. To do this, select the corresponding check boxes. If the geometric conditions are not met, an error message appears before the calculation.
Figure 02  Calculation Parameters
First, enter the elements of the crosssection. The notional flat widths are usually generated automatically from the geometry conditions, but can also be created as userdefined in Table "1.7 Notional Flat Widths  EN 1993‑1‑3" (Figure 03) or in the corresponding dialog box.
Figure 03  Table 1.7 Notional Flat Widths  EN 199313
Then, you can define stiffeners in Table "1.8 Stiffeners" or in the corresponding dialog box (Figure 04).
Figure 04  Table 1.8 Stiffeners
Furthermore, you should specify the buckling panel in Table "1.9 Buckling panels" (Figure 05) or in the dialog box. To do this, select the elements of the buckling panel. The stiffeners located in the stiffened panel are identified automatically.
For the design of a coldformed crosssection in RF‑/STEEL Cold‑Formed Sections, it is sufficient to define the stiffeners and panels of the crosssection. It is not necessary to additionally calculate the effective crosssection in SHAPE‑THIN. Thus, you can start the calculation and click "OK" to confirm the warning message (Figure 06).
Figure 06  Warning "Effective CrossSection Values Cannot Be Calculated"
After saving the calculated crosssection, it can be imported into RFEM or RSTAB.

Answer
The Design According to Formula column lists the equations of the standard used to carry out the design.The abbreviations stand for the following designs:CS Crosssection designST Stability analysisSE Serviceability (SLS design)The numbers directly behind it are internal information.The lower table of the intermediate values shows the design formulas with the design conditions that are relevant for the selected design.
Contact us
Did you find your question?
If not, contact us via our free email, chat, or forum support, or send us your question via the online form.
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.
Your support is by far the best
“Thank you for the valuable information.
I would like to pay a compliment to your support team. I am always impressed how quickly and professionally the questions are answered. I have used a lot of software with a support contract in the field of structural analysis, but your support is by far the best. ”