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)
Customer Support 24/7
AnswerIn RF-/JOINTS Steel - Rigid, the design is implemented according to EN 1993‑1‑8, Section 6.2.7, Equation 6.24. If the design axial force exceeds 5% of the plastic resistance Npl, Rd, Equation 6.24 applies.
AnswerThe design of a rigid connection of this type without a web stiffener or an end plate is only possible with the JOINTS Steel - Rigid add-on module. You can find an example under Downloads below.
AnswerThe option to enter a taper on a beam can be activated in the Arrangement section of Window 1.4 Geometry. Here you can model the taper on the bottom or top side of the beam.The plate thicknesses as well as the height of the taper are defined by selecting the cross-section of the taper, since the cut rolled cross-sections are often used, for example. If user-defined plates are used, you can select a parametric T‑section. The length of the taper as well as the material are entered in the same section. The weld thicknesses for connecting the taper to the beam can be defined in the Welds section.If there is a tapered member already used as a beam (entered in the "Nodes and Members" section by specifying different cross-sections and lengths), it is not possible to model an additional taper.
AnswerIn addition to geometry input errors, this discrepancy is usually caused by a different calculation basis of both add-on modules.The design of an end plate joint with the RF‑/JOINTS Steel - DSTV add-on module is carried out by comparing the saved ultimate limit states with the design internal forces. The underlying resistances are taken from the current DSTV guidelines.When using the RF‑/JOINTS Steel - Rigid add-on module, the joint resistances of are calculated according to DIN EN 1993‑1‑8 by means of the component method. Thus, you can directly affect the results via the settings you have made.In this case, an elastic distribution of bolt forces is used as a basis by default. By selecting the plastic force distribution in the joint, you can activate additional load capacities. These are already included in the ultimate limit states according to the DSTV guidelines.In order to obtain the comparable results between both add-on modules, it is necessary to apply the plastic force distribution for the calculation. Furthermore, you should pay attention to the correct modeling of the joint geometry.
The geometry depends on the definition of the structural components. In Window "1.2 Nodes and Members," there is the specification of which member is calculated as a column and which one as a beam. The program always recognizes the column as a continuous structural component by default (see Figure 01).In order to make the beam continuous, simply change the status of the individual members (see Figure 02). The actual beam will have the "Column" status and the actual column will be defined as a "Beam."
AnswerIn the current standards, fasteners or connections are always designed in one plane only. The reason for this is that the designs for shear etc. can only be analyzed in the 2D plane. The hole design, for example, is not possible for a failure from the plane.Since internal forces in v y and v z can always occur in a three-dimensional calculation, it has been proven in practice to allow a small proportion of internal forces in secondary direction and not fully utilize the connection. However, if the ratio of shear force in secondary direction is too high, a detailed analysis with an FE simulation might be necessary.
The easiest way to find the internal forces at these nodes is to print the pictures of members into the printout report.
If this solution is not an option, you can also find the values in the result table 4.1 in the printout report. Since the extreme values are only activated by default, it is still necessary to activate nodal values in the selection.
It is usually not reasonable to include the internal forces of all member in the printout report. Therefore, you can only select the members that are relevant to you.
Designs in our module RF-/JOINTS Steel - Rigid are based on the assumptions and regulations of the standard EN 1993‑1‑8. Here, bending from the main beam plane is not considered.
In RFEM, it is possible to model any rigid joint. All internal forces can then be taken into account.
RF-JOINTS performs an idealized design of a steel connection according to the standard, which cannot be easily compared with an exact FE calculation.
Thus, the following conditions must be met:
- Consideration or exclusion of friction/compression/tension within the contact solid (tab 'Solid') as well as for the bolts modelled subsequently
- Consideration of internal forces and deformations within the subsequently modelled end plates or similar, which causes redistribution of bolt forces in the FE calculation (in contrast to the idealized design in RF‑JOINTS)
This can be corrected by rigid connection objects, for example (an end plate as a rigid surface).
- Uniform load introduction into the FE model, for example, by using rigid members or rigid surfaces as described in the article 'FEM Modeling Approaches of Rigid Connections'
In the RF‑/JOINTS add-on module, you can export result graphics as DXF files. The corresponding button is below the graphic in Window 4.1 (see Figure 01).
After you click the button, the Windows dialog box "Save as" appears where you can enter the name and the file path of the DXF file.
Did you find your question?
If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.
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.
“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. ”