# Frequently Asked Questions (FAQ)

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• ### How can I model several simply supported beams in a row in CRANEWAY?

You can model several single-span beams in a row by inserting releases:

• Activate "Release" in Window "1.2 Geometry", see Figure 01.

• Edit the releases in the "Releases" tab that becomes active.

• ### I have the SHAPE‑THIN 9 license, but I cannot transfer the created cross-section into the RFEM program. What is the problem?

The problem is in the RFEM version. SHAPE-THIN 9.01 was released together with the RFEM version 5.22.01. The files created in SHAPE‑THIN 9 have the format *.du9. The RFEM versions older than 5.22.01 do not recognize this extension, and thus the cross-sections created in a newer version cannot be loaded.
• ### What flow model and type of analysis is used in RWIND Simulation?

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RWIND Simulation uses a numerical CFD (Computational Fluid Dynamics) model to determine the airflow around objects using a digital wind tunnel.

RWIND Simulation is designed to use a variety of numerical solvers. We currently recommend the OpenFOAM ® software package, which showed very good results in our tests and is also a widely used tool for the CFD simulations.

The numerical solver is called "RWINDSimulationSolver" and belongs to the SIMPLE solver family. It is a solution for incompressible turbulent flow at steady state by using the SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithms.
• ### What is the formula used to calculate the ASCE 7 wind velocity profile?

The wind velocity profile in RWIND Simulation according to the ASCE 7-16 standard [1] is calculated based on Eq. 26.10-1. The coefficients and basic wind speed in this equation below are incorporated in the wind pressure equation.

Velocity wind pressure (imperial): qz = 0.00256 Kz Kzt Kd Ke V2

We must reference this equation to calculate the inlet velocity relative to elevation for the RWIND Simulation CFD wind tunnel. To consider only velocity rather than pressure from this equation, the basic wind speed is multiplied by the square-root of each coefficient. Notice the velocity variable in Eq. 26.10-1 is squared which requires the square root of the coefficients to be considered.

$Inlet\;velocity\;=\;V\sqrt{K_e\;\cdot\;K_{d\;}\cdot\;K_z\;\cdot\;K_{zt}}$

Because the ASCE 7-16 standard does not address wind CFD analysis and magnitude of the required inlet velocity, it is difficult to draw comparisons. Therefore, this is the closest estimate for calculating the RWIND Simulation inlet wind velocity per the code.

• ### According to which regulation or standard are composite beams designed in the program COMPOSITE‑BEAM 8.xx?

The COMPOSITE‑BEAM program allows for design of composite beams according to the preliminary standard ENV 1994‑1‑1:1992:10.

Until further notice, the pre-standard is only implemented. The design according to EN 1994‑1‑1 is currently not possible.

See also the product description of COMPOSITE‑BEAM on the product page under the following link.

• ### When running PLATE‑BUCKLING as a stand‑alone program or as an add‑on module within RFEM/RSTAB, the "from RFEM" or "from RSTAB" button is grayed out.

If the PLATE‑BUCKLING add-on module is not opened as a stand-alone version, but via RFEM or RSTAB, it is possible to import the panels (c/t parts of a member cross-section) and the respective load cases of the RFEM or RSTAB model to PLATE‑BUCKLING (see the figure).

If there are no valid cross-sections of PLATE‑BUCKLING found in the model file of RFEM/RSTAB, the option for importing the buckling panels remains inactive.
• ### Is the Gust-effect (G or Gf) from the ASCE 7-16 Sect. 26.11 considered in RWIND Simulation?

Yes, the Gust-factor G or Gf, can be adjusted in RWIND Simulation. This value can be changed within the "Wind load" tab under "Wind velocity."

In the ASCE 7-16, the conservative value for the Gust-factor, G, is 0.85 for rigid buildings. The engineer can calculate an alternative and more accurate value. The Gust-effect, Gf, for flexible buildings accounts for size and gust size similar to rigid buildings but also considers dynamic amplification including wind speed, natural frequency, and damping ratio.

• ### Will other standards be added to the wind profile generation options in RWIND Simulation?

Additional standards and codes to generate the wind profile automatically in RWIND Simulation will be added in the future. We are always considering feedback from our current customers on which standards will be beneficial.

• ### Does software RWIND Simulation account for the internal pressure coefficient (GCpi) from the ASCE 7-16?

The internal pressure coefficients do not need to be considered with in the RWIND Simulation program.

RWIND Simulation always outputs the net pressure on the surfaces in RFEM. When it comes to a simulation with a building that has open windows in RWIND Simulation, there is an internal pressure acting on the inside of the building. The program uses this information to determine the resulting pressure based on the external and internal surfaces. This can be seen in Figure 1.

A comparison cannot be made between this coefficient in the standard and a CFD calculation because there is no direct correlation.

• ### Is it possible to manually adjust detail categories or a stress cycle of the detail categories?

You can control the detail categories in Window "1.3 Cross-Section" and in the "Edit Detail Categories" dialog box.

The specified standard values can be selected here. Unfortunately, it is not possible to manually adjust these values.

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#### First Steps

We provide hints and tips to help you get started with the main programs RFEM and RSTAB.

#### 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.

#### Your support is by far the best

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