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Frequently Asked Questions (FAQ)
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AnswerThis is because the effective lengths or buckling lengths of bars and staff sets differ. While the actual length of the bars is used for the proof of stability, for bar sets it is the length of the combined bars.exampleThe frame shown in the picture (see picture 1) consists of a bar divided into 4 bars of equal length. In addition, a set of rods is created for the 4 rods. The proof of stability is carried out for both cases according to the substitute rod method.When dimensioning the bars, the length is calculated to be 1.00 m. In contrast, the rod set is 4.00 m long (see Figure 2). Of course, the difference in lengths has an effect on the stability rating, which means that the workloads also differ (see Figure 3)It is also not recommended to calculate all bars and sets of bars in a design case, as this leads to falsified results.
AnswerIn the HolzPro module, double rectangular check cross sections (H-2B cross section) can only be dimensioned with a constant cross section height over the bar length. Gevoutete H-2B cross-sections are excluded from the design. In such a case, it makes sense to depict the two rectangular cross sections as individual rectangular cross sections. Either one models the two bars geometrically separated from each other and couples them eg with rigid bars, or one activates the option "Allow double bars" in the menu item "Edit" and assigns the two bars, which are initially on top of each other, corresponding eccentricities. These bars can then be dimensioned in the add-on module HolzPro. At the bottom of the Downloads section is an example file available.
You have probably carried out the design in RF‑/TIMBER Pro according to DIN 1052:2008 and used a cut-to-grain angle of less than 3° (see Figure 01). According to Section 10.4.1 (1) of DIN 1052, such a cut-to-grain angle does not need to be considered. If you switch the design to the current DIN EN 1995 (see Figure 02), the design will also be carried out for the angle of less than 3°.
Furthermore, the module allows you to analyze transversal tension stress in the apex etc., according to the Section 6.4.3 ff. of the Eurocode. This procedure is explained in detail in the webinar.
AnswerThe deduction of the superelevation in the usability test is actually not regulated in steel construction. However, in response to multiple customer requests, we have adopted this in accordance with the wood or concrete additional modules. According to the standard specification, however, this value should only be taken into account in the quasi-permanent design combination.This does not apply to the characteristic and frequent design situation. As soon as the design situation in the add-on module is adjusted accordingly (see picture), the applied camber is also subtracted from the resulting deformation.
AnswerIn the basic information, the rod sets must first be selected so that they can be dimensioned for the corresponding limit states. Thereafter, various requirements for the proof of serviceability can be made in the usability parameters.
I have modified cross-section properties or reduced stiffnesses of a members in RFEM/RSTAB. After a new calculation, the deformation of the structural system has adjusted itself to the new cross-section properties. However, this change is not taken into account when performing design in add-on modules.
In principle, the modified cross-section properties are not transferred into add-on modules, such as RF‑/STEEL or RF‑/STEEL EC3. They are only used for the calculation of internal forces.
In the add-on modules, stresses are calculated using the real cross-section dimensions, which cannot be modified. This would be difficult to implement as many designs require the element width or height and due to the modification, it is not known which parameter has been reduced exactly. This is important for the c/t-designs in RF‑/STEEL EC3, for example.
If a different cross-section is used in the add-on module than in RFEM / RSTAB, it is displayed in blue. It should also signalize that the internal forces are determined with the cross-section defined in RSTAB / RFEM (in Figure 01: IPE 300), but the design is carried out in the add-on module with the cross-section assigned there (see Figure 01: IPE 80). The cross-sections have different cross-sections if the cross-section in the add-on module has been modified manually or optimized by the program.
You can either read the cross-section from the RFEM / RSTAB again (select "Edit → Import Cross-Section from RFEM / RSTAB") or transfer the cross-section of the add-on module to the main program (menu "Edit → Sending Cross-Section to RFEM / RSTAB", see Figure 02). And. The cross-sections are then identical again and are displayed in black.
Yes, it is possible. For reasonable predimensioning of cross-sections in RF‑/TIMBER Pro, you can optimize any cross-section of the relevant cross-section serie.
In the case of a local dongle, you can activate the new add-on module very quickly using the authorization file.
We provide you this file immediately after your purchase via e-mail or our extranet.
If you use a network dongle, the only thing you need to do is to write the new information in it.
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