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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AnswerIt is often the case that the member dimensions do not match.In the example model, the beam has a flange width of 200 mm and the column support of 160 mm.This joint is not allowed in the add-on module because the flange width of the column should be at least as large as the flange width of the structural element to be connected. As soon as the cross-sections are defined according to this rule, the connection design is also satisfactory.
The defined stiffness modifications are only considered in the RF-STABILITY Stability Analysis if the option “Activate Stiffness Modifications from RFEM” in “Options” of the menu “1.1 General Data” is activated.
To ensure that the cross-sections are recognized when directly importing girders and columns in REVIT, a corresponding family must be available for these components in the REVIT project.
If this is not the case, you can import a suitable family into your project during the import process. The interface then independently recognizes all other cross-sections and creates the corresponding cross-sections within the family.Figure 01 does not show a 480/520 (mm) timber column. After importing the correct family type, this cross-section and all other cross-sections of the same type are recognized and the import process is successfully completed.
With the national annex ÖNORM B 1991-1-3: 2018-12, Austria has redrafted the width of the tolerance zones textually.
 In the third paragraph under the heading "Annex B", the standard accordingly states that within 2.5 km on both sides of the zone boundary, the characteristic value sk is the average of the affected zones. In the area of Vienna, we can assume a 250 m per side. This results in a tolerance zone width of 2 x 2.5 km = 5 km inland and of 2 x 250 m = 500 m in Vienna.
→ See Snow Load Map of Austria
This guideline was applied when updating to ÖNORM B 1991-1-3: 2018-12 on our website Snow, Wind and Seismic Zones.
AnswerBasically, elements in RFEM are rigidly connected. To solve this problem, two elements are suitable in RFEM. The line joints and the line releases. The difference is explained in the link below.
In this case, you have the option to print the image in the time course diagram directly into the printout report. Proceed as described in the picture.
AnswerRFEM provides an interface to software programs developed by the Dlubal company. The input data of allPredecessor versions are imported without problems. Also the files of the framework program can be opened directly and supplemented with area or volume elements. Conversely, you can also open RFEM 5 files in RSTAB 8.There is a direct link to the CAD applications ofand (but not for LT versions). With RFEM, the advantages of BIM ( ) to exchange data models for digital planning.
AnswerIn the program, you can enter a final temperature of the steel. This function has been implemented to use e.g. results from real fire events or fire test locations and carry out the analyzes with a more accurate temperature, since the temperature rise is usually divided into several phases in real firing and thus is more favorable for the design.When carrying out design on the level of temperature, it turns out that the highest temperature that occurs in the structural component is less than the critical steel temperature. The critical steel temperature is the temperature at which the component resistance is just as high as the loading due to mechanical loads.This is not a design according to ULS, since no stability analyzes are usually carried out in this case. Therefore, it is possible to use this method for the preliminary design of a structural component by calculating e.g. the critical temperature using the factor of utilization for the moment loading. We do not offer this method directly, but you have the possibility to determine a critical temperature of the structural component iteratively by specifying the temperature, but I would recommend to consider the stability analyzes. The determined critical temperature may be smaller than the one of the formulas in the Eurocode, because as usual, no stability analysis is considered.
The following points should be considered to ensure that the determined internal forces can be used for the design:
The model should represent the real structure as exactly as possible. For this, materials, surface thicknesses, cross-section dimensions, hinge definitions, support conditions, etc. must be defined correctly.
The loads must be defined and applied according to standards. The combinatorics can be imported automatically by RFEM.
When considering internal forces from result combinations, care must be taken to evaluate the correct max / min values. The maximum compressive force in a column corresponds to the minimum axial force (min N).
The standard EN 1991-3, Table 2.2., presents load groups 1 to 10. These are equal to the denotation of the classes in our software.
The integration in Categories A to E is a specific classification by Dlubal Software.
- Category A: Ultimate limit state → Table 2.2 of the standard: ULS (1-7)
- Category B: Test load (8)
- Category C: Accidental (9,10)
- Category D: Serviceability limit state (11-13)
- Category E: It was added to the combinatorics on customer request and should be used for the load cases where the support forces from the crane girder design are combined with the related structure.
The article of our Knowledge Base (see Links below) points out that the combinatorics (Classes A to D) should be used for the preliminary design of crane girders. For the supporting structure (brackets, supports, trusses), this combinatorics should not be used.
In your model, the support loads from the crane girder design are only considered in Category E.
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