0 Votes

Timber Design

Last modified by Iwona Budny Bjergø on 2022/01/18 12:23

Fast auto design and check are available to find the most suitable timber bar cross-sections and panel types.

The table summarizes the available timber design features by FEM-Design module.

Design element typeDesign feature

1585567535192-424.png

1585567539811-401.png

1585567547551-783.png

1585567589528-997.png  Timber BarAuto design1585567785526-451.png1585567789385-212.png1585567791998-123.png
 Manual design1585567787527-322.png1585567799189-610.png1585567797847-865.png
1585567599610-278.png  Timber PanelAuto design  1585567796216-305.png
 Manual design  1585567794801-156.png

Table: Timber design features by FEM-Design module

Load-Duration Classes

Based on Eurocode 5 (EN 1995-1-1:2004), load-duration classes can be taken into account in the Timber design.

The load-duration classes are characterized by the effect of constant load acting for a certain period of time in the life of the structure. For a variable action the appropriate class shall be determined on the basis of an estimate of the typical variation of the load with time.

Actions shall be assigned to one of the load-duration classes given for strength and stiffness calculations.

Load-duration classOrder of accumulated duration of characteristic loadExamples of loading
PermanentMore than 10 yearsDead load
Long-term6 months – 10 yearsStorage
Medium-term1 week – 6 monthsImposed floor load, snow
Short-termless than one weekSnow, wind
Instantaneous Wind, accidental load

Table: Load-duration classes and examples of load-duration assignment (EN 1995-1-1:2004)

warning.pngSince climatic loads (snow, wind) vary between countries, the assignment of load-duration classes may be specified in the National annex.

1585568088172-114.png

Loads can be assigned to load-duration classes with the Load cases command in the 1585568112061-308.png  Tabmenu.

1585568075545-537.png

Figure: Load cases and load-duration classes

Timber Bar

Global Auto (timber bar) design (Calculate > Design calculations > Auto design all structural elements) finds the most suitable cross-section (from the profile range set at Auto design > Parameters) for all timber bars (columns, beams and truss members) based on their initial calculation parameters, internal forces and detailed utilization calculations. With Manual design you can run quick utilization check for given profiles by bar elements and/or design groups. You can also do quick Auto design by elements and design groups only instead of global design. Of course, any number of design cycles is executable, so the global Auto design can be combined with both previous and additional element-based Auto designs.

No.Global timber bar designElement-based timber designCombined timber design
11585568277471-663.png  Calculation parameters1585568294649-630.png  Global Analysis1585568305280-777.png  Calculation parameters
21585568283625-592.png  Design group1585568301211-704.png  Calculation parameters1585568288642-927.png  Design group
31585568337842-761.png 1585568422160-545.png  Auto design > Parameters1585568286969-293.png  Design group1585568345505-573.png 1585568427293-597.png  Design Parameters
41585568329524-956.png  Global Auto design1585568340952-966.png 1585568424103-406.png  Auto design > Parameters1585568415737-427.png  Global Auto design
51585568317303-546.png  Documentation1585568342457-825.png 1585568433618-565.png  Auto design by elements1585568356036-155.png 1585568425542-915.png  Auto design > Parameters
6 1585568454606-396.png  Manual design by elements1585568408106-114.png 1585568436192-169.png  Auto design by elements
7 1585568446953-768.png  Apply design changes1585568441613-443.png  Manual design by elements
8 1585568325452-526.png  Global Check1585568448775-837.png  Apply design changes
9 1585568315024-933.png  Documentation1585568324252-720.png  Global Check
10  1585568318577-564.png  Documentation

Table: Recommended steps by design alternatives

Initial Calculation and Design Parameters

All bar design calculations needs internal forces from Analysis calculations applied for Load combinations or Load-groups, 1585568488193-104.png  Buckling length and initial design settings defined by 1585568495719-721.png  Design calculation parameters.

1585568557865-972.png

Figure: Design calculation parameters

Auto Design

1585568572597-786.png

Global Auto design gives utilization results and suitable profiles for all timber bars of the current project from a defined range of cross-sections.

1585568590742-994.png

Figure: Global Auto design and utilization result

light.png

The recommended profile names can be displayed on screen by showing the “Timber bar, applied quantity” object layer, or click 1585568770762-374.png  Design tool of the Auto design and the parameters together with utilization results are available in table format. Utilization as colored figure (color palette) can be displayed by selecting New result > Timber bar > Utilization.

Applied profiles are displayed in blue in the Utilization table, if they are assigned to the timber bars during design, otherwise black color represents the original/initial profiles.

1585568792084-334.png

Element-based Auto design finds the most suitable profile of timber columns, beams and bars for selected unique or grouped members only from a range of available profiles defined by 1585568808304-519.png  Parameters. The design utilization can be limited between 10% and 100% with Limit utilization.

1585568819449-166.png

Figure: Range of available profiles for design

To run element-based design for the load combinations or the maximum of load groups, select the required members and/or group with the Auto design command and click 1585568829094-751.png  Design tool. The quick process results recommended profiles and their utilization. Check the Display table box to have a look at the overall design results (see the figure before).

The upper table shows the design efficiency and the maximal utilization of the designed single members and groups based on the given design parameters. The bottom table displays the utilization details of the bar or the members of the group selected in the upper table.

 MeaningNote
1585568837300-375.pngSuitable profile is available 
1585568842439-743.pngSuitable profile is not availableModify the range of available profiles or timber materials
GroupID of a single bar or a group name 
Design parametersThe defined range of available profiles 
Applied profileProfile currently assigned to the bar 
MaxMax. utilization of a single bar or the significant member of a group 
MinMax. utilization of the less significant group member 
BarID of a single bar or a group member 
TUtilization for combined bending and axial tensionAccording to Eurocode 5: 6.2.3
CUtilization for combined bending and axial compressionAccording to Eurocode 5: 6.1.4, 6.2.4
SUtilization for combined shear and torsionAccording to Eurocode 5: 6.1.7, 6.1.8
FB1Utilization for flexural buckling around axis 1According to Eurocode 5: 6.3.2
FB2Utilization for flexural buckling around axis 2According to Eurocode 5: 6.3.2
LTBUtilization for lateral torsional bucklingAccording to Eurocode 5: 6.3.3

Table: The meaning of symbols, design parameters and utilization results

Quick redesign can be done inside the Utilization table:

  1. Select a bar or a design group in the upper table.
  2. Modify the range of available profiles for the select element under Parameters.
  3. Click Design.

Save /load default sections

For each section type (e.g. Dressed lumber, Glulam, etc.) a set of sections can be saved/loaded as default.

1585568935264-404.png

This will only work with one type cross-section (e.g. only Glulam, or only Sawn lumber) selected. Otherwise, with Save command, the user can save a set of arbitrary sections into a file, and use them later for another model by Load command.

Manual Design

icon_manualdesign2

With Manual design quick utilization check can be done for given timber profile and for selected timber beam, column, bar or design group only. Just, choose the load type (load combination or load group) and a profile name from the drop-down lists and select a bar, bars or group, and program displays detailed utilization results in table format.

1585569003612-119.png

Figure: Quick check by Manual design

warning.pngThe meaning of the utilization components, the table content and features are the same as written before at Auto design. The program use the chosen profile for all selected bar elements.

Detailed Result

Utilization of timber bars can be displayed in the following cases:

  • After global Auto design, you can display utilization of all timber bars checked for the recommended profiles.
  • When running element-based Auto design, utilization can be displayed by designed elements.
  • After Manual design, element-based Check displays utilization for selected elements.
  • After global Check done for all bar elements having final cross-section.
No.Global Auto designElement-based Auto des.Element-based CheckGlobal Check
11585569049246-495.png  Calculate>Design calculation>Auto design all structural elements1585569099302-291.png  Auto design

1585569103701-188.png  Auto design and/or

1585569112371-834.png  Manual design

1585569105956-992.png  Auto design and/or

1585569114179-915.png  Manual design

2

1585569061287-259.png  New result > Timber bar

1585569072453-779.png  New result >Timber bar1585569125075-613.png  Check1585569119919-730.png  Apply changes
3  

1585569075089-516.png  New result > Timber bar

1585569130850-485.png  Calculate > Design calculation > Auto design all structural elements
4   

1585569076625-251.png  New result > Timber bar

Table: Steps of displaying timber bar utilization by different design cases

1585569172532-147.png

Utilization displayed with New result appears for all designed bars. The utilization components for a bar/design group can be displayed with Detailed result.

Detailed result opens a new window in the current project after selecting a bar/group member, which displays:

  • Applied cross-section
    The figure displays the applied timber cross-section with its main calculation parameters.

    1585569196268-519.png

    Figure: Applied cross-section
  • Detailed calculation formulas
    Calculation details and final values are collected by checking types: Combined bending and axial tension (Eurocode5: 6.2.3), Combined bending and axial compression (6.1.4, 6.2.4), Combined shear and torsion (6.1.7, 6.1.8), Flexural buckling around axis 1 and (6.3.2) and Lateral torsional buckling (6.3.3). The proper results are displayed in green, while the red result warnings you to repeat design with new bar properties. The content of the utilization checks depends on Display options. Not relevant checks can also be hidden.
  • Summary graph
    Summary graph is displayed with legend by default. Numeric values can be inquired in the calculation sections (set by Design calculation parameters).

    1585569221742-479.png

    Figure: Utilization checks, formulas and summary

1585569238918-392.png  Tabmenu contains the following tools and settings:

  • Selection of element to display
    You can choose a unique or a design group member from the drop-down lists to display its detailed results mentioned before. Each row displays the ID and the maximum utilization of a member. In case of a design group, “Maximum” means the significant member having the maximum utilization.
  • Selection of design load
    Depending on timber design was done for load combinations or load groups, a load combination or the maximum or a significant component of load groups can be selected for detailed results. Each row displays the name of the load combination/load group component and its utilization effect. “Maximum” means the significant load combination or component of load groups.
  • 1585569528985-957.png Auto design

    Quick Auto design can be done for the currently displayed unique/group member. Its design parameters can be set/modified in the appearing dialog, and then clicking OK starts timber design that updates all detailed result figures and formulas.
     
  • 1585569566814-684.png Manual design

    Manual design can be launched directly for the currently displayed unique/group member.
     
  • 1585569607268-997.png Display options

    The content and the appearance of the detailed result can be set with Display options. You can show only the final equation without details of the different checks (Hide details).

    1585569631622-596.png
    Figure: Display options of Detailed result
     
  • 1585569657689-790.png Go to

    Navigate in the detailed result window by selecting the required design type in the drop-down list. It is useful when you are in zoomed view.

1585569685742-398.png Click Tools > Add view to document to place all figures, fomulas and summary table or specified details only into Documentation.

Timber Panel

Global Auto (timber panel) design (Calculate > Design calculations > Auto design all structural elements) finds the most suitable type (from panel type range set at Auto design > Parameters) for all timber panels (plates and walls) based on internal forces and detailed utilization calculations. With Manual design you can run quick utilization check for given panel types by elements and/or design groups. You can also do quick Auto design by elements and design groups only instead of global design. Of course, any number of design cycles is executable, so the global Auto design can be combined with both previous and additional element-based Auto designs.   

warning.pngTo define a timber panel (slab or wall) read more at Timber Panel Element.
No.Global timber panel designElement-based timber designCombined timber design
11585569782863-347.png  Design group1585569815852-451.png  Global Analysis1585569787500-511.png  Design group
21585569796716-815.png 1585569840599-579.png  Auto design > Parameters1585569784927-430.png  Design group1585569802194-695.png 1585569845156-647.png  Design Parameters
31585569813382-363.png  Global Auto design1585569798305-780.png 1585569842779-912.png  Auto design > Parameters1585569818980-178.png  Global Auto design
41585569831643-884.png  Documentation1585569800427-126.png 1585569872149-336.png  Auto design by elements1585569803894-613.png 1585569847037-361.png  Auto design > Parameters
5 1585569864911-795.png  Manual design by elements1585569806601-153.png 1585569900081-243.png  Auto design by elements
6 1585569857814-526.png  Apply design changes1585569866574-917.png  Manual design by elements
7 1585569823396-236.png  Global Check1585569859750-196.png  Apply design changes
8 1585569833219-990.png  Documentation1585569825484-464.png  Global Check
9  1585569834966-658.png  Documentation

Table: Recommended steps by design alternatives

Auto Design

1585569961949-288.png Global Auto design gives utilization results and suitable panel type for all timber panels of the current project from a defined range of panel types.

1585569937333-642.png

Figure: Global Auto design and utilization result

light.png

The recommended panel type names can be displayed on screen by showing the “Timber panel, applied quantity” object layer, or click 1585569999526-645.png  Design tool of the Auto design and the parameters together with utilization results are available in table format. Utilization as colored figure (color palette) can be displayed by selecting New result > Timber panel > Utilization.

Applied panel types are displayed in blue in the Utilization table, if they are assigned to the timber panels during design, otherwise black color represents the original/initial types.

1585570013988-380.png Element-based Auto design finds the most suitable type of timber panels for selected unique or grouped members only from a range of available types defined by 1585570028135-503.png  Parameters.

1585570033635-298.png

Figure: Range of available timber panels for design

To run element-based design for the load combinations or the maximum of load groups, select the required members and/or group with the Auto design command and click 1585570050865-452.png  Design tool. The quick process results recommended panel types and their utilization. Check the Display table box to have a look at the overall design results (see before).

The upper table shows the design efficiency and the maximal utilization of the designed single panel element and groups based on internal forces. The bottom table displays the utilization details of the panel or the panel members of the group selected in the upper table.

 MeaningNote
1585570057464-429.pngSuitable panel is available 
1585570061802-425.pngSuitable panel is not availableModify the range of available panels or timber materials
GroupID of a single panel or a group name 
Design parametersThe defined range of available panels 
Applied typePanel type currently assigned to the panel 
MaxMax. utilization of a single panel or the significant member of a group 
MinMax. utilization of the less significant group member 
PanelID of a single panel or a group member 
Sx+ / Sy+Utilization for x/y-directional tensionAccording to Eurocode 5: 6.2.3
Sx- / Sy-Utilization for x/y-directional compressionAccording to Eurocode 5: 6.1.4, 6.2.4
TxyUtilization for shear, xyAccording to Eurocode 5: 6.1.7
Tx / TyUtilization for shear, xz /yzAccording to Eurocode 5: 6.1.7

Table: The meaning of symbols, design parameters and utilization results

Quick redesign can be done inside the Utilization table:

  1. Select a panel or a design group in the upper table.
  2. Modify the range of available panel types for the select element under Parameters.
  3. Click Design.

Manual Design

1585570137928-454.png With Manual design quick utilization check can be done for given types of selected timber panels or their design groups only. Just, choose the load type (load combination or load group) and a type name from the drop-down lists and select a panel or panel group, and program displays detailed utilization results in table format.

warning.pngThe meaning of the utilization components, the table content and features are the same as written before at Auto design. The program use the chosen type for all selected panels.

1585570188564-371.png

Figure: Quick check by Manual design

Detailed Result

Utilization of timber panels can be displayed in the following cases:

  • After global Auto design, you can display utilization of all timber panels checked for the recommended panel types.
  • When running element-based Auto design, utilization can be displayed by designed elements.
  • After Manual design, element-based Check displays utilization for selected elements.
  • After global Check done for all panel elements having final thickness (type).
No.Global Auto designElement-based Auto des.Element-based CheckGlobal Check
11585570225883-128.png  Calculate>Design calculation > Auto design all structural elements1585570302046-138.png  Auto design

1585570300302-419.png  Auto design and/or

1585570282879-848.png  Manual design

1585570298439-851.png  Auto design and/or

1585570285218-939.png  Manual design

2

1585570272729-473.png  New result > Timber panel

1585570270968-477.png  New result > Timber panel

1585570309456-775.png  Check1585570291940-242.png  Apply changes
3  

1585570274826-849.png  New result > Timber panel

1585570230338-636.png  Calculate > Design calculation > Auto design all structural elements
4   

1585570276743-225.png  New result > Timber panel

Table: Steps of displaying timber panel utilization by different design cases

1585570320191-228.png Utilization displayed with New result appears for all designed panels. The utilization components for a panel/design group can be displayed with Detailed result.

Detailed result opens a new window in the current project after selecting a panel/group member, which displays:

  • Applied panel type
    A list displays the applied timber panel type with its main calculation parameters.

    1585570347630-496.png
    Figure: Applied timber panel type
  • Detailed calculation formulas
    Calculation details and final values are collected by checking types: Tension and bending (Eurocode5: 6.2.3), Compression and bending (6.1.4, 6.2.4), Shear, xy (6.1.7) and Shear, xz and yz (6.1.7). The proper results are displayed in green, while the red result warnings you to repeat design with new panel types. The content of the utilization checks depends on Display options. Not relevant checks can also be hidden.
  • Summary graph
    Summary graph is displayed with legend by default.

    1585570378743-462.png
    Figure: Utilization checks, formulas and summary

1585570402913-240.png  Tabmenu contains the following tools and settings:

  • Selection of element to display
    You can choose a unique or a design group member from the drop-down lists to display its detailed results mentioned before. Each row displays the ID and the maximum utilization of a member. In case of a design group, “Maximum” means the significant member having the maximum utilization.
  • Selection of design load
    Depending on timber design was done for load combinations or load groups, a load combination or the maximum or a significant component of load groups can be selected for detailed results. Each row displays the name of the load combination/load group component and its utilization effect. “Maximum” means the significant load combination or component of load groups.
  • 1585570421864-251.png Auto design
    Quick Auto design can be done for the currently displayed unique/group member. Its design parameters can be set/modified in the appearing dialog, and then clicking OK starts timber design that updates all detailed result figures and formulas.
  • 1585570428515-156.png Manual design
    Manual design can be launched directly for the currently displayed unique/group member.
  • 1585570436353-419.png Display options
    The content and the appearance of the detailed result can be set with Display options. You can show only the final equation without details of the different checks (Hide details).

    1585570444480-166.png
    Figure: Display options of Detailed result
     
  • 1585570455251-108.png Go to

    Navigate in the detailed result window by selecting the required design type in the drop-down list. It is useful when you are in zoomed view.

1585570462658-647.png Click Tools > Add view to document to place all figures, fomulas and summary table or specified details only into Documentation.

 

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