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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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.
AnswerUnfortunately, groups of members cannot be designed in STEEL EC3. A continuous member can only be created and selected to design continuously connected members.
AnswerUnfortunately, this is not possible. The design module can only be used together with the internal forces from RSTAB or RFEM.
AnswerIn this case, it is recommended to use the module extension RF-/STEEL Warping Torsion :RF-/STEEL Warping Torsion is an extension of the RF-/STEEL EC3 and RF-/STEEL AISC add-on modules. It performs flexural-torsional buckling analyzes of members according to the second-order analysis with seven degrees of freedom and a form of imperfection affecting the mode shape.You can find more information in the links below this FAQ.
You can find this setting in the 'Details' of the 'Fire Resistance' tab.You can also control the time of fire resistance individually for each member or set of members.Subsequently, it is possible to find the input in Table 1.10 for the members or 1.11 for the sets of members.
AnswerIn the RF-/STEEL add-on module, an equivalent stress design is performed according to von Mises. An elastic stress design (EL-EL) is to be made. In RF-/STEEL EC3, a classification is carried out before the design. If the cross-section is classified as class 1 or class 2, the design is performed against plastic limit internal forces. An EL-PL design is performed. If you do not want to use the plastic load reserves, you can switch the design to EL-EL in the details of the RF-/STEEL EC3 add-on module. The results are then comparable with RF-/STEEL.
Most likely, the error is in the selection of the cross section:
For a steel design, a thin-walled flat steel cross-section should be selected instead of a rectangular solid cross-section, see Figure 1.
The reason for the high shear stress of a solid cross-section is caused by the existing stress points of the cross-section or by the corresponding thickness of this stress point.
In the case of a thin-walled flat steel cross-section, there are four stress points at the corner points of the cross-section with the corresponding thickness t = 10 mm, see Figure 2.
For a solid cross-section, however, there is another stress point in the center, where the maximum of height h or width b is assumed as the thickness t for this cross-section type. In this case, the width b is 200 mm, see Figure 3.
This results in a small torsional section modulus Wt and a correspondingly high shear stress.
Therefore, the solution is, as described above, to select flat steel within the main program.
AnswerSince the equivalent member designs of Eurocode 3 have different interactions than are the case for the designs according to the partial internal forces method and a mixture of these different designs is not desired for reasons of clarity, RFEM deactivates the equivalent member designs when using the RF-/STEEL Plasticity add-on.
The term "shear panel" indicates that the translational spring, which is created along the beam length by means of the shear panel type including the corresponding parameters, is smoothed, see Figure 1.
This is also the case for the shear panel type "Bracing", so that the mode shape always appears to be arbitrary at this location, see Figure 2.
In order to obtain accurate results, it is recommended to manually define a lateral support by means of a nodal support according to the general method (Figure 3) or to define the effective lengths according to the equivalent member method, including intermediate restraints, if necessary. Finally, a eigenvector with visible lateral restraint in the mid-span is created (Figure 4).
One support was defined at a node that is not part of the set of members in the window ‘1.7 Nodal Supports’ of RF-/STEEL EC3. In this case, it is necessary to define support at a node existing in the set of members or delete this nodal support in the window '1.7 Nodal Supports' of RF-/STEEL EC3.
In Figure 1, for example, a set of member supports was defined for the set of members 1 on nodes 2 and 7. When the calculation starts, the message 'Node No. 7 with support does not exist in the set of members No.1. Please correct this in Table 1.7.' appears (Figure 2, Figure 3).
In window ‘1.7 Nodal Supports’ of the RF-/STEEL EC3, it is possible to get displayed only the selected set of members by clicking the 'Show Only Current Object' button and the node numbering can be displayed by clicking the 'Local Coordinate System' button (Figure 4). It is obvious that the node 7 is not contained in the set of members. Instead of at node 7, the support must be defined on a node contained in the member set (for example, node 6).
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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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