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)
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Live load reduction is not considered automatically in RFEM. RFEM and RSTAB are general FEA and framework programs. The program does not understand what is a floor element vs wall element. Only a general plate element is defined. It is not possible for the program to determine the area of a floor for live load reduction.A user must manually consider the reduction by modifying the live load magnitude directly in the load application.
AnswerIn RFEM, the easiest way is to use the "Plane Surfaces" → "Annulus" feature. This allows you to model the reinforcement rings very quickly and easily. Then you can extrude the inner line into a surface, the chimney is already generated. Now, the existing annular surface is copied upwards and the corresponding stiffeners are modeled. You can use the "Rotate" command to distribute the stiffeners over the chimney perimeter.
AnswerThis is not possible directly in RFEM, but the RF‑/STEEL EC3 add-on module allows you to create a list of steel parts. In Details of the add-on module, you can specify whether the parts list should apply to all members or only for members to be designed. Then, you can simply carry out the calculation and the parts list will be displayed. It is also possible to export the parts list to Excel and further edit it.
AnswerThe 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 Cross-section 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.
AnswerIf the PLATE‑BUCKLING add-on module is not opened as a stand-alone version, but via RFEM or RSTAB, it is possible to import the panels (c/t parts of a member cross-section) and the respective load cases of the RFEM or RSTAB model to PLATE‑BUCKLING (see the figure).If there are no valid cross-sections of PLATE‑BUCKLING found in the model file of RFEM/RSTAB, the option for importing the buckling panels remains inactive.
AnswerA thread cannot be created using a function in the program. In such a case, you have to create this geometrically via nodes and lines. In the program, there is an option to create the windings through trajectory surfaces. However, you have the option to reach your target relatively quickly when using Copy and Rotate.
AnswerUnfortunately, groups of members cannot be designed in STEEL EC3. A continuous member can only be created and selected to design continuously connected members.
AnswerWith the PLATE-BUCKLING add-on module, you can only calculate rectangular buckling panels.The panel is entered via 1.1 of the add-on module. Alternatively, the panel can also be created from an existing RFEM or RSTAB file by selecting the respective c/t-part.
Orthotropic surfaces are non-linear and cannot be designed within the RF-STEEL Surfaces add-on module. It is possible to get a full stress analysis in RFEM for the orthotropic surfaces defined with the orthotropy type "constant thickness" and compared to limiting stresses manually. For all other orthotropy type, the program is not aware of the geometric properties for the surface at every FE mesh point which is needed to calculate stresses. An extensive and detailed FE model would need to be created. See FAQ 2468 for an example of this. Surface types need to be set to "standard" to be designed within the add-on module.
Section F2 out of the AISC 360-16  states that doubly symmetric I-Shapes and Channels that are bent about their major axis must be compact sections in order to be designed. An example of this can be seen below.Non-compact sections cannot be designed according to F2. Figure 2 shows a non-designable section.
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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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