Frequently Asked Questions (FAQ)

As of version RFEM 6.02.0071, the RSECTION cross-section is imported into RFEM through the Dlubal Center (Image 01).

In order to access the file in the Dlubal Center, the RSECTION file can be saved in the Dlubal folder (Image 02). Make sure the file is saved inside the “examples” folder.

The file can also be saved in a different location by choosing the option to Add existing project and selecting the relevant folder (Image 03). Do not use the Create new project option.

The RSECTION file can then be found under Models in the "Projects" folder (Image 01).

Bolt holes in thin-walled cross-sections calculated with the “Thin-Walled Analysis” design method can be modeled using null elements.

In general, you can use null elements to bridge failure locations or holes in the cross-section, for example, if the cross-section only has a hole at this analyzed member location and before / after the complete cross-section provides the connection in the member. Using the null element, it is possible to transfer the shear in the failure location, and also to apply Steiner's components to the section properties.

In the case of a null element, the thickness t is equal to zero. For the calculation of shear stresses, the thickness of the adjacent elements is used as usual, as these elements exist in front of and behind the hole (viewed in the longitudinal direction of the member). For the shear thickness t *, we recommend specifying the thickness of the thinnest element adjacent to the null element.

In the Effective Length dialog box, you can simply uncheck the "Lateral Torsional Buckling" option to exclude this check in the design add-on.

1. Define a plane that will be used to apply the load. You can do so by creating 4 corner nodes around your structure (Image 01).

2. Go to Insert→ Load Wizards→ Member Loads from Area Loads. Specify the direction and magnitude in the Main tab (Image 02).

3. Select the Geometry tab and select the corner nodes that were previously created. (Image 03).

4. Select the Tolerances tab and enter a distance that will capture the entire width/height of the structure (Image 04). Click OK to exit.

5. Right click on the area load and select Display separately. The area load is now displayed as member loads (Image 05).

The weld-affected zone strengths listed in the Material Values are currently not being considered by the program. The weld design is being developed and will be considered in the future.

Below are the steps to consider the reduced strengths:

1) Activate the User-defined material option (Image 01)

2) In the Material Values tab, re-enter the weld-affected zones strengths in the standard strengths (Image 02)

3) To consider the weld-affected zone strengths only at the end of the members, divide the member into smaller segments and assign the applicable materials (Image 03)

4) To keep the divided members as one continuous member, select all the members and right-click to Create Member Set (Image 04)

The main programs RFEM 6 and RSTAB 9 are distinguished by their clarity. The entire input in the program is set up in such a way that you always obtain a clear result for each calculation task. The design of objects is organized in a similar way. In the input, the program shows the necessary properties for each design object, including the corresponding loads, and outputs a clear result for this object after the analysis.

If you want to determine your own design results for the entire model for different load levels, the "Construction Stages Analysis (CSA)" add-on provides a solution. In addition to the basic simulation of the construction process (the object rise), the program also allows for parallel simulation of models with a constant number of objects. In this special case, the base model is internally juxtaposed several times, and can thus be transferred to the design with different loads.

To do this, proceed as follows:

1. Activate the "Construction Stages Analysis (CSA)" add-on in the Base Data.
2. In the Navigator, under the "Construction Stages" item, define the required stages with the "Start" attribute and activate all elements.
3. Assign the respective load for each stage in the "Load Cases and Combinations" menu, "Construction Stages" tab.
4. After the calculation, evaluate the design depending on the defined stages.

Some materials have multiple limit stress limits for compression, tension, and so on. For these materials, the limiting stress must be input manually by the user.

The limit stress values are listed under the Material Values tab.

These values can be added in the Member/Surface Configurations under the User limit stress type.

All members when using the Design Add-ons for serviceability checks are considered supported at the end nodes by default. If the member is instead a cantilever or includes an internal support for a combination of both a cantilever and supported at both ends member type, a new Design Support should be defined under the member details.

The Design Support option can be found under the member dialog box under Design Supports & Deflection tab. Supports can be added to any nodes detected along the member length such as the member start, member end, or internal nodes.

Under the New Design Support dialog box, you can set the type of support from the drop-down including general, concrete, or timber. The "general" will give the program guidance on the deflection member type and which limiting deflection ratio to reference from the Serviceability Configurations whether cantilever (e.g., L/180) or supported on both ends (e.g., L/360). The alternative types "concrete" and "timber" will also influence the deflection design, but have additional strength design options incorporated such as moment and shear internal force modification for concrete design and a stress perpendicular to grain check for timber design.

For additional detailed information on this new setting in RFEM 6 including a "timber" type design support, refer to the webinar listed below under Links at time 51:05.

1) Select Create New Design Situation and edit the design situation name. Clear the Combination Wizard option by selecting “- -” in the drop-down menu (Image 01).

2) In the Load Combinations tab, copy the selected load combination(s) and assign the newly created user-defined design situation (Image 02).

3) In the Assignment tab, the load cases and factors may be adjusted for the assigned CO (Image 03).

In order to make the Material Library more compact and well-arranged, the materials of the individual National Annexes, as listed in RFEM 5 and RSTAB 8, have been replaced by a single material in the new programs. Since the materials are identical, apart from a few exceptions, the material according to CEN is now provided for design. For this, select the "European Union" region (see Image 01).

Materials of this region can be used in the corresponding design add-ons regardless of the specified National Annex of a design standard.

If there are any deviations defined in the respective National Annex, they are taken into account accordingly on the design page (see Image 02).