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Frequently Asked Questions (FAQ)
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AnswerTo enter a taper on a beam, it is necessary to select the Layout dialog section. A taper can be modeled either on the bottom side or on the top side of the beam.The plate thicknesses, as well as the height of the taper, are defined by selecting a tapered cross-section, since, for example, repeatedly cut rolled cross-sections are used. If any plates are used, a parametric T-section can be selected. The length of the taper, as well as the material, are entered in the same dialog section. The weld thicknesses for connecting the taper to the beam can be defined in the Welds dialog section.If a tapered member is already used as a beam (entered in the 'Nodes and Members via Different Cross-Sections and Lengths' section), it is not possible to model an additional taper.
AnswerIf stiffeners are welded into the crane runway, the corresponding notch category according to EN 1993-1-9, Table 8.4, detail 7 has to be considered for the fatigue design. This is implemented in CRANEWAY by creating additional stress points at the connection point of the stiffeners to the section. They can be adjusted manually in the settings for the detail categories depending on the geometry of the stiffener.During the fatigue design of the craneway girder, the design of the axial stress range is additionally performed in the newly created stress points for the x-locations on which a stiffener is provided.
AnswerIn the case of long crane runways and many cranes, the large number of load combinations can lead to a long calculation time. The following settings affect the calculation time significantly:
Calculation method for determining the internal forces
The fast calculation type may therefore be useful for the preliminary design.
- Fast calculation (calculation of all load combinations according to the 1st-order analysis, then calculation of the governing load combinations according to second-order analysis for torsional buckling)
- Detailed calculation (calculation of all load combinations according to second-order analysis for torsional buckling)
Maximum target length of the finite elementsThe maximum length of the finite elements generated for the calculation according to the second-order analysis for torsional buckling can be entered within a range of 100 mm to 2500 mm. The calculation time can be increased significantly by the finer division of finite elements.Thus, you should select a reasonable length of the finite elements for an optimized calculation time depending on the structural system. Usually, 8 elements for each girder span are enough to calculate the deformations with a deviation of less than 5% relative to the precise solution.
Number of load combinationsYou can use a reasonable setting of the load increment to control the number of generated load combinations. When entering the load increment, the generated number of crane load positions and load combinations is already displayed in a preview. A small load increment may result in many load combinations that take accordingly more time in the calculation.
AnswerWith the FE mesh refinement, it is also possible to create an aligned FE mesh in the program. Thus, the automatic FE mesh generator can be controlled to a certain extent. However, it is not possible to use it for setting of a specified mesh geometry.
AnswerIn addition to geometry input errors, the cause is usually the different calculation principles of both 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 load capacities with the design internal forces. The underlying load capacities are taken from the current DSTV guidelines.When using the RF-/JOINTS Steel - Rigid add-on module, the capacities of the connections are calculated according to DIN EN 1993-1-8 by means of the component method. Thus the results can be directly influenced by the used settings.By default, an elastic distribution of bolt forces is used as a basis. By selecting a plastic force distribution in the connection, you can activate additional load capacities. They are already included in the limit load capacities according to the DSTV-guideline.Therefore, to obtain comparable results between both add-on modules, a plastic distribution of forces must be applied for the calculation. In addition, it is important to ensure a correct modeling of the connection geometry.
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.
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