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)
Customer Support 24/7
Shows the main load direction in the RF-LAMINATE add-on moduleWhile entering data in the RF-LAMINATE add-on module, you can graphically control the orthotropic direction of each individual layer. To do this, simply place the cursor in the desired row of the corresponding position. Then, a coordinate system is displayed in the surface in the RFEM model (see Figure 01). This is to be interpreted as follows:red axis = x-axis = β-value of the corresponding layerGenerally, the outer layers specify the main load-bearing direction, which is why it is sufficient to consider only the first layer. The red axis specifies the main load direction (see Figure 01).
Display of the main load direction in RFEMHowever, the main load direction can also be interpreted directly in RFEM. The local axis systems of the surfaces can be displayed in detail (see Figure 02). The orthotropic direction β refers to the local x-axis of the surface. For the example shown in Figure 03, this means that the main load-bearing direction for the left surface runs from the supports to the supports and the secondary surface direction to the right surface. If you want to change the supporting direction for the right surface, you can either rotate the local surface axis system (see Figure 04) or create a new structure and rotate the orthotropic direction β by 90 ° (see Figure 05).If the principal load-bearing direction is not clearly evident, it is worth taking a look at the stiffness matrix of the surface (see Figure 06). There you can, for example Based on the bending stiffness, the "strong" load-bearing direction can be found. The element D 11 refers to the local x-axis of the surface and the element D 22 refers to the local axis y of the surface.
AnswerThe superstructures of manufacturers of cross-laminated timber products are stored in the central database of RF-LAMINATE.We continuously extend and maintain this database.If you want to include a manufacturer in the database, you can request a sample file from us where you can save its setups. Furthermore, it is helpful if the manufacturer sends us information regarding the reduction factors regarding torsional stiffnesses, shear stiffnesses, side facing strains, and so on.
AnswerThe detailed procedure can be found in the video. It indicates the most important features:
AnswerThe program VERBUND-TR for the design of composite girders is designed according to ENV 1994-1-1: 1992-10. This standard specifies a composite cross-section consisting of steel section and reinforced concrete. The design according to EN 1995-1-3 is carried out for the design of composite beams consisting of timber and reinforced concrete. In this case, the time-dependent load conditions t = 0, t = 3-7years and t = infinite have to be analyzed in particular. These states are usually taken into account by means of the imposed strains, which is currently done in the RFEM Manual program. For this and many other reasons, it is not possible to design timber-concrete composite beams in the VERBUND-TR program.However, on our homepage you can find a lot of information about the design of timber-concrete composite beams, for example here.
The setting in Figure 01 only controls the influence on the design side. After activating this function, the buckling designs in the "Effective Lengths" window are deactivated. Thus, only a lateral-torsional buckling analysis is performed.In order to calculate with the design values of the stiffnesses, they have to be reduced by the partial safety factor according to  . To do this, select the marked option in the calculation parameters (see Figure 02).If the automatic combinatorics was used for the standard EN 1990 + EN 1995, this setting is automatically activated for combinations for the ULS according to the second-order analysis. For combinations for SLS, this option is automatically deactivated as well as for combinations generated according to the 1st order. However, the automatic assignment is only carried out by means of the calculation type in the "Combination Expressions" window (see Figure 03).If you want to calculate the component stiffnesses with the 5% quantile value of the stiffness parameters divided by the partial safety factor, you have to additionally activate the "Modify Stiffness" function in the calculation parameters and modify the stiffnesses manually.
AnswerFor many users, the very realistic display of a building in construction programs arouses the wish to carry out the structural analysis of this building with the same complex spatial model.Again and again, the design of log cabins is approached to us. Unfortunately, this attractive construction method is relatively complex for three-dimensional analysis. The dimensioning results in some critical questions that cannot be answered.
Furthermore, log houses are common for houses with a maximum of 2 full floors because of their high placement of more than 15 cm per storey. Thus, the occurring forces are within a manageable framework and can be determined sufficiently precisely with the methods of the structural analysis for members in 2D structures. In RFEM/RSTAB, there is an option to define rounded bars in a tapered way for this purpose. Thus, the definition of 2D equivalent systems can be done much faster in RFEM/RSTAB.There is some information in the given literature source.
- Which sorting class is the timber subject to? In a log house, damp unsorted timber is often used.
- How is the contact between the timber types regulated? Diamond notch, connection with moving timbers etc.?
- Have mullions been installed? Which type of timber and how are they supported horizontally?
- Which dimensions does the timber have? In a log construction, a grown trunk can often be integrated. These trunks do not have uniform dimensions because nature cannot be put into a grid.
- How is it possible to consider contact between two layers of a timber?
AnswerYes, that is possible. The output is available in the menu File → Export to DXF. To also include possible stiffening elements, it is necessary to complete the calculation first and then carry out the export. Otherwise, the stiffening elements will not be output in the DXF. The elements such as nodes, supports, and geometry are written into different layers and can be deactivated as required in the CAD program.
AnswerThe RF-/JOINTS add-on module is divided into several joint groups. For this, see the following FAQ.Therefore, there is no straightforward answer to the special aspects of the design as in this FAQ.In contrast to the RF‑/TIMBER Pro add-on module described in the mentioned FAQ, however, it is obvious that the RF‑/JOINTS add-on modules cannot design EC2, even if manually changing the LDC, for example in the RF‑/JOINTS Timber - Steel to Timber add-on module (see Figure 01).Furthermore, this also applies to the add‑on modules RF‑GLASS and RF‑/CONCRETE NL.The reason for this is that there are stiffnesses exported in the program in the case of some joint groups of the RF‑/JOINTS add‑on module. For nonlinear calculations, the superposition with result combinations is not allowed. In the case of the second result combination mentioned above, there is the special feature that the superposition is no longer conservative, even in the case of simple structures. The design cannot be also performed correctly by manually changing the LDC.Nevertheless, if a result combination should be superimposed with constant and alternative additive, it is necessary to split EC2 in the attached file into load combinations as follows.
- RC2*=CO1 or CO2
AnswerIn general, all result combinations can be designed with the RF‑/TIMBER Pro program. However, there is the special feature in timber construction, that the governing load combination is not the combination with the largest internal forces due to the load duration class (LDC).In the case of the result combinations, it is necessary to distinguish between 4 basic types of combinations.
In this respect, there is a special feature of the combination from the RF‑/DYNAM Pro add‑on module. In this case, the results are constantly superimposed and additionally squared. However, these combinations are then comparable with the third combination mentioned above.Results used in TIMBER Pro for each result combination.
- Permanent and additive (+/-) superposition of all actions.
- Actions different in permanent or variable, but additive (+/-) superposition.
- All actions permanent, but superimposed with 'or'.
- All actions variable, but superimposed with 'or'.
- The maximum moment in the attached file is used. The 'Short' LDC is correctly taken into account.
- In a simple example, the moment is correctly taken into account. However, a support moment on the continuous beam can be taken into account incorrectly. The LDC in RC2 is considered as 'permanent' by default. Therefore, the design becomes very unefficient and must be changed in this case (see Figure 02). However, 'permanent' might be correct for the continuous beam mentioned above.
- In the case of RC3 and RC4, there is a pure result evaluation, which is possible in all design modules.
AnswerFor concentrated loads in the vicinity of the support, it is mandatory to apply the smaller transversal compression coefficient of kc,90 according to Section 6.1.5 (4) of the Eurocode 5.Optionally, it is possible to deactivate the support compression design in the program RX-TIMBER and to do corresponding transversal compression reinforcements.If the entered concentrated load is not relevant for design, the user has the additional option to assign the transversal compression factor with a user-defined assignment (Figure 3).
Did you find your question?
If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.
Your support is by far the best
“Thank you very much for the useful information.
I would like to pay a compliment to your support team. I am always impressed how quickly and professionally the questions are answered. In the industry of structural analysis, I use several software including service contract, but your support is by far the best.”