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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AnswerLong-term losses are considered directly before the design process in the external add-on module RF‑TENDON Design. In this case, the internal forces in the examined design sections are recalculated by applying the long-term losses. The detailed results and the individual loss components can be found under "Action Phase."
AnswerYes, it is considered. The resulting internal forces due to prestressing can also be displayed accordingly (see Figure 01).Primary Forces: Statically determined part of the internal forces due to prestressingSecondary Forces: Statically undetermined part of the internal forces due to prestressingTo display the individual parts, you have to create a new result class (RC) where the prestressing load case is only selected.
AnswerThe add-on module is designed for pre-tensioning or post-tensioning prestress. The templates for the tendon geometry are based on parabolic diagrams. This means that the modules are not designed explicitly for the design of flat slabs.Possible Procedure:The geometric distribution for a free tendon position cannot be determined automatically by the add-on modules. However, it is possible to use a user-defined tendon distribution as a basis. Unbonded prestress could be set by adjusting friction coefficients.The deformation analysis cannot be performed in the RF‑TENDON and RF‑TENDON Design add‑on modules. However, it is possible to perform the deformation analysis by using RFEM in conjunction with RF‑CONCRETE NL or RF‑CONCRETE Deflect when applying equivalent prestress loads. The equivalent prestress loads are exported without the influence of long-term losses and would have to be reduced by a factor corresponding to these losses in RFEM.
AnswerRF-TENDON is an external add-on module. While RF-TENDON is running RFEM is locked via COM connection. RF-TENDON is not integrated in RFEM and it runs as a separate application. RF-TENDON should appear in the taskbar after it was started (picture 1)
AnswerThe module RF-TENDON is designed as a module for members. However, it is also possible to provide surfaces with tendons via the member type Result beam and to calculate them.An example of a disk calculation is shown in the following webinar:
AnswerThe RF-TENDON module can be opened via the menu bar under Additional modules → RF-TENDON (see Fig. 1). The module RF-TENODN. which serves for the subsequent cross-sectional dimensioning can be opened out of RF-TENODN (see Fig. 2).The modules are only available in RFEM. Both modules are also available in the student version.
When creating a new cross-section in RFEM/RSTAB, there are various cross-section types available for selection in the 'Parametric - Massive' category. If you stay with the mouse cursor on the button for a while, an information appears, indicating in which add‑on modules you can design this cross-section (see Figure 01).
The cross-sections marked in green in Figure 01 can be designed with CONCRETE (RSTAB) and RF‑CONCRETE Members (RFEM). On the other hand, a 'Pi‑section, type A', is not suitable for the design with CONCRETE or RF‑CONCRETE Members. As you can see in the info, the cross-section can be analysed with RF‑TENDON. Therefore, you can select this cross-section for a member in RFEM and design it in the RF‑TENDON Design add‑on module.
Why it is not possible to design all cross-sections in CONCRETE or RF‑CONCRETE Members?
It is because of the reinforcement layers available for the individual cross-section types: for example, if you create and design a rectangular cross-section, you will find the corresponding reinforcement layer in Window 1.6 of CONCRETE, it means the possible reinforcement distribution (see Figure 02). There are various reinforcement layouts possible for a rectangular cross-section. These reinforcement layers are required to determine stresses and strains in the cross-section and thus the required reinforcement.
For other cross-sections, such as Pi‑sections, this information is not available in the current state of development. Therefore, they cannot be designed with CONCRETE or RF‑CONCRETE Members.
If the SHAPE‑MASSIVE program is licenced, you can create the structural system with a Pi‑section in RFEM/RSTAB and determine the governing internal forces. In SHAPE‑MASSIVE, it would then be possible to define the cross-section, to import the internal forces from RFEM/RSTAB and to design the cross-section according to the manual specification of longitudinal reinforcement.
Further information about SHAPE‑MASSIVE can be found under the following link: https://www.dlubal.com/en/products/cross-section-properties-software/shape-massive
SHAPE-MASSIVE allows you to freely define thick-walled cross-sections.
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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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