#### Further Information

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• ### How can I select the members that have a certain material?

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For the design of steel cross-sections, it is recommended to only select the members that also have steel as the material. This can be easily controlled in the Views navigator by activating the "Members by Material" option and setting the desired material (see the figure).

• ### After dividing a column with intermediate nodes, the results in the RF‑/CONCRETE Columns add-on module are different from those before the division. What is the reason?

The reason for the different results is probably the settings of effective lengths for the stability analysis. According to the default setting, these are determined automatically in the RF‑/CONCRETE Columns add-on module. However, this method does not work for divided members, and thus no stability analysis is performed (a corresponding warning message appears).

If you have entered the effective lengths manually, this only applies to a single member. In order to perform a correct stability analysis of the column as an entire structural component, it is necessary to define it as a set of members.

• ### Is it possible to design member groups with the EC3 module?

Unfortunately, groups of members cannot be designed in STEEL EC3. A continuous member can only be created and selected to design continuously connected members.
• ### How can I create an intersection point between a line and a surface?

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The intersection between surfaces and lines can be created with the "Connect Lines/Members" function. To do this, select the "Connect Lines/Members" function and then draw a window over the elements to be intersected (Figure 01). A node will be created at the intersection point. This is also shown in the video.
• ### What is the easiest way to delete a node of two crossing members?

Unfortunately, there is no automated function for this. In this case, you can use the drag-and-drop function to move the node to one of the corner nodes and then create the crossing members again.
• ### How can I transfer a field of nodes instead of just a single node via the COM interface in VBA?

To transfer several elements, you have to create a field (array) in VBA first:

Dim nodes(0 to 2) as RFEM5.Node

Then, you can use the method IModelData.SetNodes() to transfer all nodes to the field (here, three elements 0,1,2) at once.

These methods are also available for the following structural elements, for example:

IModelData.SetLines()IModelData.SetMembers()IModelData.SetSurfaces()
• ### I recently purchased RSTAB with the CONCRETE add-on module. Can I use it to perform the stability analysis of reinforced concrete columns?

Yes, you can, because the nonlinear reinforced concrete design is also included in the CONCRETE add-on module for RSTAB 8. Thus, you can activate "Nonlinear calculation" in the "Ultimate Limit State" tab.

In the detail settings for the nonlinear calculation, you can select "General design method for members in axial compression acc. to second order theory."

In this case, it is important to define the imperfections in RSTAB and apply load combinations (CO) according to the second-order analysis, no result combinations (RC), for the design!

###### Note to RFEM 5:

In RFEM 5, the same procedure is possible in RF‑CONCRETE Members. However, RFEM requires the RF‑CONCRETE NL add-on module for the nonlinear reinforced concrete design.

• ### In the global calculation parameters, the "Exceptional handling" option for members is grayed out and cannot be activated. What is the reason for this?

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This option is only available if there are nonlinear structural elements (for example, tension members) included in the structure. You can easily check if this is the case. Open the global calculation parameters and check in the "Nonlinearities" section at the bottom left whether the "Members due to member type" or "Member nonlinearities" option is available. If they are grayed out, there are no members with these parameters and the "Exceptional handling" option is thus unavailable, because there will be no failing members in such case.
• ### Is there an easy way to create a spatial structure from a 2D model, whereby the nodes in columns and lines will be extruded into walls?

For lines, this option is already available directly in the shortcut menu. For extruding nodes into members and lines in surfaces, there is the corresponding option in the detailed settings of Copy/Rotate/Mirror. As soon as at least one copy is generated, the new elements will also be created.
In case this feature is not wanted anymore, it should be deactivated in the detailed settings again.
• ### I design a set of members by using the equivalent member method in RF‑/STEEL EC3, but the calculation fails. The system is unstable, delivering the message "Non-designable - ER055) Zero value of the critical moment on the segment."What could be the reason?

Please check if all sets of members selected for the design are straight sets of members. The equivalent member method is only applicable for straight sets of members with a uniform cross-section, so no taper is applicable, for example. In this case, use the preset General Method.

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If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.

#### 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.

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