Module "Wall"

The input is divided into:

wall dimensions and boundary conditions
cross section
design loads and design factors
stability
connection wall floor
fire

In the current version, only rectangular wall elements without openings can be calculated. The wall is defined via a wall height and wall length.

The bearing of the wall at the top and bottom edges is hinged and the lateral edges are free. These boundary conditions cannot be changed at present.

In this module, the cross section is defined in the direction of the wall length (vertical cross section) and the width of the cross section cannot be changed.

See Module "CLT-Plate 1D - Continuous beam"

Input data

The input is divided into:

general information about the project and the considered structural element
definitions of the structural system
definitions of the cross section
input of the loads
informations about fire and vibration parameters

A graphical representation of the input data is shown on the right side. This offers the possibility for a fast check of the input data.

General

The input field "General" defines the service class. It is only allowed to use CLT elements in areas of service class 1 and 2.

Service class 1 (interior service condition) is in general consistent with a common utilisation of living spaces.
Service class 2 (protected exterior service condition) is generally used for open but roofed structures.

Structural system

In the current version a continuous beam with a maximum of 7 spans including a cantilever on the left and right side can be analysed. The supporting width and span of field (via x-value in the table) can be defined within this input field.

Cross section

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.

Syntax of the csv file

name;number of layers n;layer thickness in [m] t₁ to t_n;orientation of the layers o₁ to o_n (0 or 90);name of material

Example:
Test layup;5;0.03;0.02;0.02;0.02;0.03;90;0;90;0;90;GL24h*

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.

Syntax of the csv file

1. row: description of the parameters
2. row: units of the parameters
3. row: value
delimiter: ";"

Example:
Name;f_m,k;f_t,0,k;f_t,90,k;f_c,k;f_c,90,k;f_v,k;f_r,k;E_0;E_0,05;E_90;G;G_r;rho_k;rho_mean;f_v,k,IP;f_T,k;f_m,k,IP
;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;N/mm2;kg/m3;kg/m3;N/mm2;N/mm2;N/mm2
Mat 1;24;16.5;0.5;24;2.7;3;1.25;11600;9667;0;720;72;380;500;5.5;2.5;21

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.

Loads

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

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

Fire

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:

Vibrations

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.

Results and output

Load combinations are compiled based on the input loads entered in the "Loads" field. The respective k_mod- and k_def-values can be determined automatically based on the classification of loads (plate weight, wind load, etc.).

Cross section values

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.

Summary of the results

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.

Detailed results

The detailed results can be retrieved in the tab "Details". The "tree" on the left side offers the possibility to choose the respective load case or combination.

The results of this choice (internal forces, deformations) are then shown for each of the calculation sections of each field (number depending on the information in the settings) in the table on the top right.

By choosing the desired calculation section in the table, the loads and supporting forces, the distribution of internal forces and the deformations as well as the calculated stresses are shown under different tabs on the bottom right.

Module "CLT-Plate 1D - Continuous beam" · 2017/11/14 17:11

The loads entered, are at design level.

The following loads can be applied:

vertical load q_d
horizontal load H_d
load q_⊥,d perpendicular to the wall

Should it be necessary to define an eccentric load application of q_d, the input of e_qd can be displayed by pressing the button .

For the calculation of the tensile force in the anchor it is necessary to know the proportion of the permanent vertical loads (percentage of g_d). Since the permanent vertical load has a relieving effect on the anchor force, this is reduced by multiplication with ξ.

By default, the horizontal load is applied at top of the wall, but can be shifted by entering Δy_Hd.

Furthermore, the design factors are specified here.

Design loads and design factors must also be specified for the case of fire.

For the verification of stability, the buckling length coefficients β_ℓk and in case of fire β_ℓk,fi have to be defined. The buckling length is then calculated from the buckling length coefficient and the wall height. The buckling coefficient k_c, which is required for the verification, is then automatically determined from the buckling length and the specific cross-section.

The straightness factor β_c and the conversion factor to the 5% quantile k₀₅ can be changed in the settings.

For the connection in the floor joint, 4 calculation models are currently available:

Tension, compression discrete & shear continuously
Compression diskret & tension, shear continuously
Tension, compression linear & shear continuously
Tension, compression, shear continuously

The chosen model should take into account the existing fasteners in the floor joint.

Depending on the selected calculation model, different inputs are required.

Tension, compression discrete & shear continuously

This model should be selected if tie rods and shear angles are used. Here the load widths for compression and tension are to be entered and an edge distance of the tie rod. The distance of the resulting tensile and compressive force is calculated automatically from this.

Compression diskret & tension, shear continuously

This model assumes continuous tensile force transmission, as for example in the case of the connection with the SHERPA CLT connector. Here, only the load application width of the compression zone has to be defined.

Tension, compression linear & shear continuously

This model corresponds to the beam theory and should only be used for very narrow wall strips.

Tension, compression, shear continuously

This model corresponds to an approximate solution of a plate loaded in plane.

Spring model

In this model, tensile and shear spring stiffnesses of discretely arranged fasteners can be entered as well as a distribution width for the respective stress direction. The contact (compressive stress) is taken into account by means of an elastic bedding (input of the bedding factor c in kN/m/m).

See Module "CLT-Plate 1D - Continuous beam"