# Frequently Asked Questions (FAQ)

#### Customer Support 24/7

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.

Receive information including news, useful tips, scheduled events, special offers, and vouchers on a regular basis.

• ### Is it possible to adjust the symbol size in the toolbar in RFEM / RSTAB?

New FAQ 003501 EN

Yes, it is possible to resize them by right-clicking next to the symbol area.
• ### I am running the program RFEM or RSTAB for the first time. How is it easiest to learn how to handle it?

New FAQ 003500 EN

You can find valuable tips on our website www.dlubal.com , be it in the form of PDF files, videos, FAQs or Knowledge Base entries. For an optimal start, we have set up an additional page for beginners with all information. Please follow the links below this FAQ.
• ### I check the cross-section properties of rolled cross-sections in SHAPE-THIN and had to find out that there are deviations in the determination of the torsional moment of inertia I t for the tables. How can this be explained?

New FAQ 003499 EN

When determining the torsional moment of inertia, point elements are not considered for I t in the analytical equations. Therefore, for cross-sections with distinct fillets such as B. rolled cross-sections, a correction factor is applied to determine the effect of the point elements. Figure 01 shows recommendations for different types of rolled cross-sections. This correction factor can be adjusted in the calculation parameters. In addition, the torsional moment of inertia can also be calculated with the FE method, which also covers the effect of point elements and welds. This approach requires slightly more computing time than the analytical calculation.
• ### In which directions do the member types "Spring" and "Dashpot" have a stiffness?

New FAQ 003498 EN

Members with the member type "Spring" or "Damper" have only axial stiffness, that is, in the direction of the local x-direction. The bending stiffness and the stiffness perpendicular to the longitudinal axis of the member are negligibly small and are not considered in RFEM and RSTAB.

Consequently, if a spring is to be used in the structure, it acts only in one direction; in the other two directions (local y- and z-direction), this member type must receive an additional support, otherwise the system becomes unstable.

• ### Is it possible to divide a free surface load by existing lines in RFEM?

New FAQ 003497 EN

Unfortunately, there is no option in the program. Here, you only have the possibility to edit the existing load and, if necessary, redefine it.
• ### When using RFEM, the problem arises that the font used in the work window is extremely small.

New FAQ 003496 EN

The font size of the title and Max / Min info can be set in the display properties. To use this function, select Options → Display Properties → Edit in the menu.
• ### Are welded stiffeners also taken into account for the fatigue design in CRANEWAY?

New FAQ 003495 EN

If stiffeners are welded into the runway girder, the corresponding notch design 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 notch cases depending on the geometry of the stiffener.

During the fatigue design of the crane runway girder, the design of the normal stress range is additionally performed in the newly created stress points for the x-locations on which a stiffener is provided.

• ### Along the axis of the structural component, I would like to define lateral supports that sometimes act on the top chord, sometimes on the bottom chord. However, only one item can be selected for each member. How can I create the input?

New FAQ 003494 EN

To provide members with different supports, it must consist of several members and be designed by a set of members. Different parameters can then be assigned to the individual members. The procedure can be found in the video.
• ### How can I optimize the calculation time in CRANEWAY?

New FAQ 003493 EN

In 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:

###### Method of calculation for determining internal forces
• Fast calculation (calculation of all load combinations according to the 1st-order analysis, then calculation of the governing load combinations according to the second-order bending-torsion analysis)
• Detailed calculation (calculation of all load combinations according to second-order bending torsion analysis)
The fast calculation type may therefore be useful for the preliminary design.

###### Desired maximum length of the finite elements
The maximum length of the finite elements generated for the calculation according to the second-order analysis for flexural-torsional buckling analysis can be entered within a range of 100mm to 2500mm. A finer division of finite elements significantly increases the calculation time.
Thus, you should select a reasonable length of the finite elements for an optimized calculation time depending on the structural system. In general, eight elements per beam surface are sufficient to calculate the deformations with a deviation of less than 5% relative to the exact solution.

###### Number of load combinations
You can use a reasonable setting of the moving step to control the number of generated load combinations. When entering the moving step, the generated number of crane load positions and load combinations is already displayed in a preview. A small increment results in many load combinations that take more time in the calculation.

• ### The display scale of the generated loads is not correct.How to solve this problem ?

New FAQ 003492 EN

When I have a trapezoidal load value that tends to zero for example, it may happen that the scale is correct for small values displayed. In this case, there is a setting error in the display properties.
It will simply proceed as follows:
• Right click on the load to access its context menu
• Select "Display Properties ..."
• Click on the magnifying glass at the height scale of size 1 [kN / m]
• Fill in eg the most minimal value of the minimum limits at 0.1%
• Confirm by clicking on OK
The scale of your drawing will be immediately adjusted and correct.

Important note :
1- The value zero is not displayed on the loads (cf. figure 3)
2- When a zero value is displayed, it certainly contains decimal digits. By zooming in, you discover that the diagram does not form a closed angle at the end. (Cf. figure 4)

11 - 20 of 1597