Module „CLT-Plate 1D - Internal forces“

The cross section can be defined by the user or by choosing a typical cross section of a proprietary CLT product. There is also the possibility to save own CLT cross sections in a library. The elements are subdivided by the number of layers.

If a user-defined cross section is entered, the thickness and orientation of each layer can be changed. Furthermore, the material can be changed for all layers. The thickness of each layer has to be within the range of 6.0 mm to 45 mm. In the case of proprietary CLT products, the strength class of lumber and the orientation can be changed. If the orientation is changed, the whole cross section is rotated.

The width of the CLT plate strips can be also defined in this field. The default value is set to 1 m. The thickness of the CLT plate is calculated automatically based on the thickness of the single layers.

The ratio of board thickness to board width can also be changed here. The default setting is 1:4.

My CLT cross sections

By clicking the button the current cross section can be stored in the library and be retrieved by selecting "My CLT cross sections" later on.

The library can be displayed with the button .

• The edit mode can be entered by clicking on . Currently, only the name of the stored cross section can be changed.
• With the changes are saved.
• With the chosen cross section in the sidebar can be removed from the library.
• With cross sections from a csv file can be imported.
• With the cross sections from the library can be exported to a csv file.

My materials

With the button the material library can be displayed.

• With the edit mode can be entered.
• With the changes are saved.
• With the chosen material in the sidebar can be removed from the library.
• With materials from a csv file can be imported.
• With the materials from the library can be exported to a csv file.

The user-defined materials are then displayed in the material selection list.

Optimization of layup

Use the button to display the window for layup optimization.

With the help of this tool, the possible layups can be determined for the given system and load situation. The optimization can be restricted with regard to producers, number of layers or by means of limits for the panel thickness. Furthermore, outer cross layers or double layers can be included or excluded. With the option "Vibration verification according to EN" the base document is included in the vibration check or not.

With the buttons "Start" and "Stop" the calculation is controlled. Please be patient, depending on the selected parameter the calculation may take a little longer.

The possible setups are then displayed in the table and the selected setup can be transferred to the main window by clicking the "Choose the selected cross section" button.

By choosing "Fire above" and/or "Fire below" in the tab "Fire" a structural fire design has to be carried out. The "Fire duration" is specified in minutes and can be increased (or decreased) by increments of 30 minutes by pressing the up (or down) arrows, or defined by entering a specific duration between 0 minutes and 240 minutes in the allotted box. By ticking the box next to "Fire protection system" a layer of fire protection is added to the plate. Furthermore, the position ("above" and/or "below") must be declared and the parameters t_ch, t_f, k₂ and k₃ must be specified. In case the failure time of the fire protection system is equal to the time until the protected component starts to burn, the option "t_f = t_ch" shall be checked.

For a user-defined cross section, options are given for specifying heat resistant adhesives, presence of grooves, and whether the layers are edge-glued. For CLT products both values are set automatically and they cannot be changed.

Some manufacturers offer CLT elements with different adhesives, so instead of selecting "Heat resistant adhesive", it is also possible to select the adhesive.

The values k_fire (conversion factor 20%-quantiles) and d₀ (layer thickness to take into consideration the influence of temperature exposure) are pre-set and cannot be changed. The charring rate is dependent on the option edge glued or without groove. For a user-defined cross section this value can be changed.

In some approvals or design proposals a different charring rate is expected from the 2nd layer onwards. This will show up as follows:

Output values generated in the tab "Cross section values" field include the effective stiffness (depending on the chosen calculation method), the position of the centre of mass for the full cross section and also for the charred cross section in case of structural fire design.