#### Further Information

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• ### What is the meaning of "shear failure of the glued-in contact surface" in the details of the RF-LAMINATE add-on module?

New FAQ 004206 EN-US

In the case of CLT panels with non- cross-laminated side and a wall-like structural behavior, the torsional stress in the glued joints is often governing. This design is performed according to the explanations in the literature reference below according to the following equation.

$\eta_x=\frac{\tau_{tor,x}}{f_{v,tor}}+\frac{\tau_x+\tau_{xz}}{f_R}=\frac{\displaystyle\frac{3\ast n_{xy}}{b(n-1)}}{f_{v,tor}}+\frac{{\displaystyle\frac{\frac{\partial n_x}{\partial x}}{n-1}}+\tau_{xz}}{f_R}\leq1$

Values:
• b Board width
• n Number of board layers
• n xy shear in pane plane
• $\ frac {\ partial n_x} {\ partial x}$ Shear the board layers
• $\ tau_ {xz}$ Thrust in thickness direction
• for shear resistance
• f v, gate Torsionsschubfestigkeit
The analysis is analogous for the y-direction, but with the values for y-direction.
• ### What does the stiffness reduction factors k33 and k88 used in RF-LAMINATE refer to?

New FAQ 004119 EN-US

These factors reduce the torsional stiffness D33 as well as the shear stiffness D88 of the corresponding stiffness matrix elements of a surface. Since cross-laminated timber is generally not laminated at the narrow side, it is also not possible to transfer shear stresses to narrow sides of a timber. Thus, the stiffness would be overvalued in this case. For this reason, the stiffness must be reduced accordingly.

Some manufacturers have already informed us about these values when transmitting the layer structures. These result from internal analysis. An explanation for determining the correction factors is presented in [1]. The analysis of this work has also been involved in the Austrian Annex to EN 1995-1-1 [2] . The result is shown in Figure 02. The ratio of board width (a) to board thickness (ti) can be taken from the corresponding authorization.
• ### Is it possible to import the effective lengths from RF-STABILITY or RSBUCK in RF-/TIMBER Pro?

New FAQ 004113 EN-US

Yes, that is possible.

First, RF-STABILITY (or RSBUCK in RSTAB 8) can be used to determine the effective lengths for a particular structure and loading.

They can then be imported in the 'Effective Lengths' of the RF-/TIMBER Pro dialog box.

• ### How can the vertical fingers be considered for a glued laminated beam?

New FAQ 004111 EN-US

In the main program RFEM/RSTAB, a member rotation of 90° is first required so that the lamellae of the glued-laminated beam are arranged on edge, see Figure 1.

To also consider the on-edge position of the beam in the design in the RF-/TIMBER Pro add-on module, increase the resistance for edgewise bending within the parameters set in the National Annex in the tab 'Other Settings 2/2', see Figure 2.

• ### Is it possible to create a second design case in RF-LAMINATE?

New FAQ 004110 EN-US

No, this is unfortunately not possible.

The layer structure is assigned to certain surfaces in RF-LAMINATE.

The respective surface is then given the stiffness defined by this layer structure for the determination of internal forces in RFEM.

If you want to perform a calculation with different layer structures, you have to do it in a copy of the file (another model with different layer structure).

• ### How to display the primary load-bearing direction graphically in RF-LAMINATE?

New FAQ 003592 EN-US

While entering data in the RF-LAMINATE add-on module, there is an option to control the orthotropic direction of each individual layer graphically. 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 layer

Generally, 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 primary load-bearing direction (see Figure 01).

###### Displaying the primary load-bearing direction in RFEM
However, the primary load-bearing 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, it has a consequence that the primary load-bearing direction for the left surface runs from one support to another and the secondary surface direction to the right surface. If you want to change the supporting direction for the right surface, it is possible to 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 primary load-bearing direction is not clearly evident, it is worth taking a look at the stiffness matrix of the surface (see Figure 06). There, it is possible to find the 'decisive' load-bearing direction, e.g. by means of the bending stiffness. The element D11 refers to the local x-axis of the surface and the element D22 refers to the local axis y of the surface.

• ### Is it possible to save the structures of manufacturer-specific cross-laminated timber slabs in the RF-LAMINATE add-on module?

New FAQ 003590 EN-US

The manufacturer-specific structures of cross-laminated timber products are saved in the central database of RF-LAMINATE.

This database is a subject of continuous extension and maintenance from our side.

If a manufacturer is supposed to be added in the database, a sample file can be requested from us to save its structures. Furthermore, it is helpful if the manufacturer provides us with information on the reduction factors of torsional and shear stiffness, the bonding of narrow sides, etc.
• ### How to model a timber-concrete composite floor?

New FAQ 003589 EN-US

The detailed procedure shows the video. It indicates the most important features:
• ### Is it possible to design timber structures with RFEM or RSTAB?

New FAQ 003575 EN-US

Both RFEM and RSTAB are ideally suited for the calculation and design in timber construction .

###### Basic programs RFEM or RSTAB
Structures, materials, and actions are defined in the basic programs RFEM or RSTAB . In addition to creating spatial frame structures, for example, halls, RFEM also provides plate, pane, and shell structures, making it a more diverse option. This pays off if you want to design in other disciplines such as solid construction.

The RF-LAMINATE add -on module is only available for RFEM.

Both programs provide the Eurocode 5 with numerous National Annexes as well as other international standards .

###### Available standards
• RF-/JOINTS Timber - Steel to Timber
Design of indirect timber connections according to Eurocode 5 or ANSI/AWC NDS 2018.
• RF-JOINTS Timber - Timber to Timber
Design of direct timber connections with inclined bolts
• RF-LIMITS
Measures, among other things, the ultimate limit state of members, member ends, knees, nodal supports, and surfaces. In addition, various fasteners from Würth SHIGA, Sherpa, Simpson StrongTie, etc. as well as end bearing supports for timber beams from Steico and Metsä Wood are included in the database.
Only in combination with RFEM:

With RX timber , you can perform designs in timber construction without RFEM or RSTAB.

• ### How can I create a rectangular timber profile in the COMPOSITE-BEAM program?

FAQ 003574 EN-US

The program COMPOSITE-BEAM for the design of composite beams is effected in accordance with ENV 1994-1-1: 1992-10. This standard specifies a composite profile consisting of steel sections and reinforced concrete.

The design of composite beams consisting of timber and reinforced concrete is carried out according to EN 1995-1-3. In this case, the time-dependent load states t=0, t=3-7 years and t= unlimited have to be analyzed in particular. These states are usually taken into account by means of impressed strains. This is done manually in the RFEM program. For this and many other reasons, it is not possible to design timber-concrete composite beams in the COMPOSITE-BEAM program.

However, on our homepage you can find a lot of information about the design of timber-concrete composite beams, for example here.

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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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