Module "Ribbed slab"

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.

The loads are divided into the dead load (weight of the plate) (g_0,k), permanent loads (g_1,k), imposed load (q_k), snow load (s_k) and wind load (w_k). This classification is necessary to automatically carry out calculations for different load case combinations.

The plate weight is calculated automatically. The calculation method can be selected in the settings/preferences window. The default calculation method is in accordance with ON B 1991-1-1. A unit weight of 5.5 kN/m³ is assumed in the calculation. However, the unit weight may also be calculated using:

• calculation based on the mean value of density of the chosen material
• calculation based on a user-defined density

When entering the imposed loads, one of the following categories has to be chosen:

• A: Areas for domestic and residential activities
• B: Office areas
• C: Areas where people may congregate (with the exception of areas defined under category A, B and D)
• D: Shopping areas
• E: Areas for storage and industrial activities
• F: Traffic and parking areas for light-duty vehicles
• G: Traffic and parking areas for medium-duty vehicles
• H: Roofs

When entering the snow load, the country code or an altitude above sea level where the structure will be located has to be specified:

• < 1000 m
• > 1000 m
• FIN, IS, N, S

The span of each field can also be modified in the table of distributed loads.

Concentrated loads can be entered in the second table. The position can be defined whether by the local or global x-coordinate.

The tab "Vibrations" allows for vibration verification.

For the vibration verification the following specifications are of importance:

• high or normal requirements? This choice will have an influence on the limit values.
• modal damping factor
• consideration of the screed (concrete topping) stiffness
  • thickness of the screed (concrete topping)
  • modulus of elasticity of the screed (concrete topping)
• support (2-sided or 4-sided)
• room width b perpendicular to the load carrying direction

The effective width b_w of the chosen cross section used by the stiffness criteria will be specified.

A summary of the verifications can be retrieved via the tab "Verifications". The utilisation ratios for various limit states are colour-coded indicating if the verification is fulfilled (green), not fulfilled (red) or a more accurate verification is needed (yellow). The locations of the maximum utilisation ratio and the governing combinations are compiled in the same way.

The tab "Utilisation" shows the distribution of the governing utilisation ratios along the beam. Areas in which the results may differ from the exact solution are marked here.

The tab "Stresses" shows the governing stresses resulting from the ULS verification. If a structural fire design was carried out, the governing stresses in case of fire are shown in the tab "Stresses in case of fire"

The tab "Deformations" shows the deformed system or the envelope given by the minimum and maximum deformation resulting from the governing SLS verification.