finnwood 2.4 - metsawood.com · manual, program version and update checks can be found ......

© Copyright 2018 Metsä Wood

FINNWOOD 2.4.1 -help manual

1

Help manual

FINNWOOD 2.4.1

EN 1995-1-1:2004+A1:2008+A2:2014 / RIL 205-1-2017

Metsä Wood

www.metsawood.fi



2

1 Introduction, the user interface FINNWOOD 2.4 interface:

The cross-section, added holes and supports of the structure in question are shown in a measured scale in the interface.

The main menu contains 4 headers: File, Database, Settings and Help.

Shortcuts at the upper left corner of the interface represent different structure types that the program can design: ”Floor beam/slab”, “Roof beam/slab”, “Column”, “Purlin beam/slab”, “Tapered beam”, “Free structure”. These different structure types can be found in the MODEL-tab and “select structure for designing” pull-down menu.

The design of a structure type is done by walking through the tabs from left to right. The tabs are:

Welcome, MODEL, Loading, DESIGN, Holes and cuttings, Additional results, and PRINTOUTS .

Finnwood is closed by choosing File > Exit.



3

The interface language (finnish or english) is selected at start up from the menu at the top of the Finnwood 2.4 –license agreement –window.



4

1.1 File menu actions – Select active project ….

By selecting File > Select active project … You can define the location where the calculations are saved.

The chosen path is shown in the Active project -field.



5

1.2 File menu actions – New calculation

“New calculation”, “Open calculation” and “Save calculation” is done with the File menu. Let’s go through an example in detail by creating a new calculation.

A new calculation is done by selecting: File > New calculation

A new window will appear showing a list of available design calculation templates. Choose a template that is best suited for Your structure type. As a default, these templates includes specific values for loads, service class and deflections for the selected calculation template. Press Cancel if You don’t want to use any of the templates from the list.

Templates are divided into the following categories:

STRUCTURE TYPES

Type of the structure part, OR primary structure / secondary structure

Service class, OR spacing / number of spans, OR precamber

The following templates are included in version 2.4:



6

Rafters are calculated with Metsä Wood’s Kerto-QP –roof beams.

In version 2.4, main columns with hinges at supports with wind load up and down are now available in the FREE STRUCTURES -category.



7

A description and a view of the chosen template is displayed to the right of the New calculation –window.

You can choose any of the templates by switching to another structure type. Shown templates belongs to the chosen structure type.



8

1.2.1 More information about the top chord of the A-frame template:

The FREE STRUCTURES type has 3 templates: “Rafter of a log house”, “Top chord of an A-frame” and “Main column with hinges at supports, wind load up and down”. Let’s take a closer look at the deflection check of the ”Top chord of an A-frame” template.

The Finnwood-program only calculates deflections for the top chord of an A-frame between the supporting points and for the cantilever. Following deflection checks must also be done for the whole A-frame structure:

1. Deflection of the ridge point ( folded main girder ) wfin ≤ L1 / 200

where L1 is the span of the A-frame

2. Deflection between the ridge and lower support point

wnet,fin = wmax – wh ≤ L2 / 300 where wmax is the biggest final deflection between ridge and lower support point

wh is the final deflection of ridge, and L2 is the span between ridge point and lower support point



9

1.3 File menu actions – Open calculation

You can create Your own calculation templates from the File menu.

Calculations from earlier versions will now open in the Finnwood 2.4.1 updated version.

Calculations made with earlier versions may give different results in the new version.

This is because the national regulations have changed slightly.



10

File menu actions - User defined calculation templates

You can create or remove Your own user defined calculation templates from the File menu.

User defined calculation templates can be saved through the File > user defined calculation templates

Enter a name to the template and press Add. The template will appear in the USER DEFINED STRUCTURES window.



11

1.4 Main headers

Cross section databases can be found in the Databases menu. See chapter 10 on how to manage databases.

Define the Calculation settings and General settings before creating a calculation. See chapter 6.4 General calculation settings for dimensioning.

This help manual, program version and update checks can be found under the Help menu.

About -window shows information about the installed Finnwood -version.



12

1.5 The coordinate system for structural parts and loads

A coordinate system according to the Eurocode 5 standard is in use in Finnwood 2.4 . See picture below.

X, Y, Z are the directions in the global coordinate system. Structures and loads are placed into this system. x, y, z are directions in a local coordinate system. The x direction runs through the center line of the structure from left to right.



13

2 Welcome tab

Under the Welcome -tab You can find the following information:

- A Brochure about Finnwood 2.4

- Finnwood help manual (this file) .

- Links to Metsä Woods web pages.

- Link to the Finnwood web page.

These links does not work without an internet connection.



14

3 The MODEL tab

Geometry, length, span and supporting types of the dimensioning structure are defined under the MODEL tab.

3.1 Geometry and supporting types of ready-made structures

Wizards for structural models, (”Floor beam/slab”, ”roof beam/slab”, ”Column”, ”Purlin beam/slab” and ”Tapered beam”) are defined as in the pictures below. Support measures S1, S2 and S3 are limited between 20…500 mm.

Support options for ready-made structures:

Fixed hinged support (X,Y,Z)

Gliding hinged support (Y,Z)

Gliding hinged support (X,Y)

Fix point (X,Y,Z,RX,RY,RZ)

Support measures limited between 20…500mm



15

3.2 Geometry and supporting methods for a free structure

Buttons shown below defines the supporting elements and geometry for the free structure.

Main supports

Main supports of the free structure:

Fixed hinged support (X,Y,Z) Optional Spring support in the Z-direction

Gliding hinged support (Y,Z) Optional Spring support in the Z-direction

Gliding hinged support (X,Y)

Fix point (X,Y,Z,RX,RY,RZ) Optional Spring support in the Z-direction

Angled gliding hinged support (Y,z)

Modify, add or remove supporting elements with these editing buttons.

First, highlight by clicking the wanted supporting element, then click on the appropriate editing button.



16

For spring supports in the Z-direction, the following stiffness values (N/mm) are available:

- Infinite, meaning stiff or none flex support

- A stiffness value, defined by the user. The value sets the amount of force that the support receives for every movement in millimeters in the vertical direction.

Side supports

Structures upper and lower side supports and intermediate supports can be added to the free structure.

Side supports are needed, if an accurate definition against buckling is required with unequally spaced supports on the upper and lower side of the structure.

For further information about this, go to chapter 6.7.1 Settings to buckling examination for a free structure. As an example, The structures upper or lower crosswise studwork or sheeting can act as side supports.

Side supports between structure parts (beams) are presumed to have the same height. Loads to the side supports are shown in the PRINTOUTS-tab when the structure is affected to a sidewise load.



17

Example: Side supports 3, 4, 5 and 6 .

Hinges

Hinges can be added to a free structure’s extension joints, where moment (My) does not charge over the splice point.



18

3.3 Kerto-Ripa slabs, defining the end supports

Longitudinal end parts of a Kerto-Ripa -slab must be equipped with a monolithic end beam or with intermediate bracings between the ribs. Also, for continuous slabs, intermediate bracings must be added at the location of intermediate supports.

Two of most common end support cases for Kerto-Ripa -slabs are shown below. Both cases can be designed in Finnwood 2.4 , if the following definitions are taken into account for support-, and span-measures:

1. Dimension S1 is the length of support beneath the rib. In supporting case B, S1 is shorter than the actual length

2. Span length is measured from the centers of the supports

3. For Kerto-Ripa -slabs, open or closed box, if the end beam is monolithic and the lower rib extends to the outer face of the end beam, as in case B, S1 and an additional cantilever dimension C1 must be defined.

Closed or open slab, supporting case A Closed or open slab, supporting case B

End support, intermediate bracings End support, monolithic end beam

Ribbed slab, supporting case A Ribbed slab, supporting case B

End support, intermediate bracings End support, monolithic end beam

NOTICE! Other supporting cases of Kerto-Ripa slabs must be dimensioned separately according to design standards.



19

4 Holes and cuttings -tab

Holes and cuttings are added under the Holes and cuttings -tab. The active element can be modified with the Edit active, Add and Remove - editing buttons. First, highlight by clicking the wanted hole or cutting, then click on the appropriate editing button.

FINNWOOD 2.4 –program version allows designing of circular and rectangular holes into Kerto®-products according to VTT certificate nr. 184/03 appendix A. These products are Kerto-S (as beam), Kerto-Q (as beam), multiple glued Kerto-S (as beam), and Kerto-QP (as beam). Notice that holes for Kerto-QP (as beam) are designed in the same manner as for Kerto-S.

FINNWOOD 2.4 –program version also allows the design of tapered/straight chamfers into Kerto®-, saw timber-, and glulam -products according to RIL 205-1-2017.



20



21

5 Loading -tab

A structures load information (point-, line-, and area -load) is defined in the Loading-tab.

Basic loads for ready-made structures, (”Floor beam/slab”, ”roof beam/slab”, ”Column”, ”Purlin beam/slab” and ”Tapered beam”) are defined in the Wizard of loading models -windows. These windows opens from the Wizard for basic load items…. -buttons. Additional loads can be added and modified from the Add, remove and edit active -buttons.

See also:

5.1 Defining loads for floor beams/slabs

5.2 Defining loads for roof beams/slabs

5.3 Defining loads for columns

5.4 Defining loads for purlin beams/slabs

5.5 Defining loads for tapered and sloped roof beams

5.6 Load cases and load combinations –window

5.6.1 Load cases and load combinations for the free structures

5.6.2 Editing/adding load cases

5.6.3 Editing/adding load combinations



22

5.1 Defining loads for floor beams/slabs

Uniformly distributed loads (kN/m2) for floor beams or Kerto-Ripa -floor/compartment slabs are defined in this window. Other load cases can be modified with the Add, Remove and Edit active -buttons.

Self-weight G1

Self-weight for structure parts and floor structure [kN/m2]. Notice, that the self-weight of a structure part can automatically be taken into account in the calculation settings (see chapter 6.4 General calculation settings). If this setting is inactive, the structures self-weight must be included in the G1 value. After calculation, check that the structures actual self-weight matches the self-weight used in the calculation.

Partition load G2

Partition load G2 is the stationary self-weight load of light non-bearing walls attached to the structure [kN/m2]. According to RIL 205-1-2017 design standard, chapter 2.3.1.4S, this self-weight load must be treated as a uniformly distributed load, with a value of at least 0.3 kN/m2.

Self-weights of movable partition walls must be treated as equally divided imposed loads, and they must be added to the compartments imposed load. If the self-weight of a movable partition ≤ 1.0 kN/m2, then the increase of the imposed load is 0.5 kN/m2.



23

Imposed load Q

Load values are defined for the imposed load [kN/m2], load classes [A-H] and load movability [%]. The table below shows the default values used in the Finnwood program. These values are according to RIL 205-1-2017 design standard, table 2.5. Movability of the imposed load is always 100%. Notice, that point load examination for the structure element must be done separately on a case-by-case basis by additional loads.

Characteristic values of uniformly distributed imposed loads by load class:

Class A Residential areas Floors 2.0 kN/m2

Stairs 2.0 kN/m2

Balconies 2.5 kN/m2

Class B Office areas Office premises 2.5 kN/m2

Class C Assembly facilities C1: Table areas 2.5 kN/m2

C2: Fixed seats 3.0 kN/m2

C3: Unobstructed areas 4.0 kN/m2

C4: Physical activities and stages 5.0 kN/m2

C5: Crowd exposed areas 6.0 kN/m2

Class D Shopping spaces D1: Retail stores 4.0 kN/m2

D2: Department stores 5.0 kN/m2

Class E Storehouses Goods storage and reception facilities 7.5 kN/m2



24

5.2 Defining loads for roof beams/slabs

Uniformly distributed loads (kN/m2) for roof beams or Kerto-Ripa roof slabs are defined in this window. Other load cases can be modified with the Add, Remove and Edit active -buttons.

Self-weight G1/G2

Self-weights of the structure element or roof element [kN/m2]. G2 is for cantilevers and G1 is between supports. Notice, that the self-weight of a structure part can automatically be taken into account in the calculation settings (see chapter 6.4 General calculation settings). If this setting is inactive, the structures self-weight must be included in the G1 and G2 values. After calculation, check that the structures actual self-weight match the self-weight used in the calculation.

Snow load Qk

Determination of snow load

specific value on ground Sk [kN/m2],

type,

form factor μ

moving part [%].

Specific value of Sk is obtained from RIL 205-1-2017 –design standard picture 2.1, shown to the right.



25

Sk can also be calculated by using the wizard of characteristic snow load -window. This wizard appears by clicking on the -button located at the right corner of the Sk text field, when it is activated. This wizard defines the snow load

according to the nearest locality.

Snow load values generated by the wizard is transferred to the Sk field by clicking on the OK-button. The Type -fields value is affected by this and will automatically be updated accordingly.

Type of snow load is ”Sk < 2.75 kN/m2” or ”Sk ≥ 2.75 kN/m2”. Values for ψ0, ψ1 and ψ2 -factors in combination loads are affected by the snow load type, according to RIL 205-1-2017 –design standard table 2.2 .



26

In RIL 205-1-2017 design standard, pictures 2.2 and 2.3 defines the form factor μ for the snow load. Below are form factors shown for single-slope roof, ridge roof, and folded roof, which are the most common cases.

Snow load is a fixed variable load, according to the EN 1991-1-3:2004 design standard. For this reason, the value for the moving part is 0 %. Snow loads for multi-spanned roof structures or roofs equipped with snow guards, has impacts on the movability of the snow load. The structural designer can inspect these impacts on the snow load by altering values to the moving parts variable.

Nominal snow load S1 is obtained by multiplying the form factor with the snow load on ground:

S1 = μ × Sk

The roofs horizontal projection is affected by S1, as shown below.



27

Wind load W1-W4

Nominal values W1 – W4 [kN/m2] are defined for the wind load, which includes possible pressure-, or suction-coefficients. Wind loads W1 and W2 affects between supports of the structure. Wind loads W3 and W4 affects the cantilevers. W1 and W3 are wind pressure (down), W2 and W4 are wind suction (up).

In RIL 205-1-2017 design standard, formula 2.5.14S defines the nominal values for W1 – W4, as follows:

Wi = cp,net × qp (h) where cp,net is the minimum wind pressure coefficient on the surface, which is the sum of (cpe) and (cpi),

the external and internal pressure coefficients qp (h) is the peak velocity pressure, where the building height (h) is taken into account

The minimum wind pressure coefficient (cp,net ) is defined in RIL 205-1-2017 design standard, tables 2.10 and 2.11. The peak velocity pressure qp (h) is defined in tables 2.8 and 2.6. The qp (h) is shown below.

Notice, that the calculation analysis for the wind load includes only dimensioning case B in RIL-205-1-2017 design standard. In other words, dimensioning of the structure is done for a local wind pressure.



28

5.3 Defining loads for columns

Vertical loads and horizontal wind loads from structures above are the basic loads for columns. They are defined in the window below. Other load cases can be modified with the Edit active, Add and Remove - editing buttons.

Vertical loads, F (self-weight, imposed load, snow load and wind load)

Self-weight, imposed load, snow load and wind load on upper level structures are vertical loads F [kN] stressing the column. These loads are assumed to be located in the upper end of the column eccentrically positioned with measures ez and ey.

In addition to defining nominal values of vertical loads, the Imposed load categories [A-H] and the type of snow load are also defined. These are explained in chapters 5.1 Defining loads for floor beams/slabs and 5.2 Defining loads for roof beams/slabs

Horizontal wind load W1

Nominal value for the horizontal wind load W1, is defined for wall piers or columns, that supports structures stressed by horizontal wind loads. This load value includes possible pressure-, and suction-coefficients, which are explained in chapter 5.2 Defining loads for roof beams/slabs.

Eccentricity measures ey and ez

All vertical loads F are assumed to stress the column with equal eccentric measures ey and ez. Equivalent torque loads caused by eccentricity are calculated for every load, and they are taken into account in the dimension.



29

5.4 Defining loads for purlin beams/slabs

Uniformly distributed loads (kN/m2) for purlin beams are defined in the window below, in a similar way as for roof beams, see chapter 5.2 Defining loads for roof beams/slabs. Other load cases can be modified with the Edit active, Add and Remove - editing buttons.

Defining the slope angle for a purlin beam

The slope angle for a purlin beam is defined in the Wizard for structural model window. See chapter 3.1. and the picture below.



30

5.5 Defining tapered/sloped beams

Uniformly distributed loads (kN/m2) for sloped beams and tapered beams are defined in a similar manner as for roof beams, see chapter 5.2. However, for a tapered beam with 2 slopes, each slope is defined separately with its own Wizard (left/right slope). Other load cases can be modified with the Edit active, Add and Remove - editing buttons.

Defining the form factor μ for the snow load to a tapered/sloped beam

The form factor μ for the snow load to a tapered/sloped beam can be found in RIL 205-1-2017, see chapter 5.2



31

5.6 Load cases and load combinations

Load cases and load combinations for all ready-made structures ( “Floor beam/slab”, “Roof beam/slab” and “Column” ) are predefined and fixed. These loads can be checked for every ready-made structure from the Loads and load combinations -window. Predefined load cases and load combinations cover basic loads for ready-made structures according to the RIL 205-1-2017 design standard. However, the structural engineer must, on a case-by-case basis, ensure their sufficiency.

An example of the Loads and load combinations -window for ”Roof beam/slab” is shown below.

Combination loads: Running numbering Load combinations participating in the calculation are marked ”ON” The content of the combination, used KFI-coefficients, partial safety value and combination factors are shown in terms Combination type (ULS / SLS) Example: 1.00×1.15×Self-weight + 1.00×1.50×Snow load + 1.00×1.50×0.60×Wind load (down) = KFI×partial safety value×nominal value of permanent load + KFI×partial safety value×determinative nominal value of variable load + KFI×partial safety value×nominal value of other variable load Note, that KFI -coefficient is automatically updated in the load combinations with respect to chosen reliability class in the DESIGN -tab

The active load combination is shown on the blue row on the gray area

Predefined load cases: load group load type duration movability (ULS and SLS)



32

5.6.1 Load cases and load combinations for free structures

Load cases and load combinations for the ready-made structures ( “Floor beam/slab”, “Roof beam/slab” and “Column” ) are predefined and fixed. However, by choosing the FREE STRUCTURES -shortcut, they are made editable. Let’s take a closer look to see how this is done:

Load cases and load combinations for free structures are shown below:

with the Edit, Add and Remove -buttons You can modify the active load case active load combination

Click on FREE STRUCTURE -shortcut or from the MODEL -tab select “Free structure“ from the ”Select structure for designing:” -list

Click on the Yes -button to activate the free structure model

Load combinations can be switched between “active” and “not active” by double-clicking on the wanted load. The indicators are ”ON” for active and ”- -” for not active.



33

5.6.2 Editing/adding a load case

It is possible for the free structure only to edit or add load cases. See chapter 5.6.1 : Load cases and load combinations for free structures. Below is the editing shown:

Click the OK -button to close the window.

Use the ADD… -button to add a new load case. This is done in a corresponding way as described above.

Name of load case Type of load case, that defines duration and ψ0, ψ1 and ψ2 -factors

Movability of the load case between span or by cantilever. ULS (ultimate limit state) and SLS (serviceability limit state) can be defined separately.

Choose a load case and click the Edit… -button

Edit the parameters in the Editing load -window



34

5.6.3 Editing/adding a load combination

It is possible for the free structure only to edit or add load combinations. See chapter 5.6.1 : Load cases and load combinations for free structures. Below is the editing shown:

Click the OK -button to close the window.

Use the ADD… -button to add a new load combination. This is done in a corresponding way as described above.

ULS (Ultimate limit state) or SLS (serviceability limit state) with or without fire/accidental design.

Combination coefficients ψ0, ψ1 tai ψ2 acc. to RIL 205-1-2017 in SLS normally ψ0 in ULS normally ψ1 ja ψ2

Partial factor acc. to RIL 205-1-2017: SLS normally 1.15, 1.35 tai 1.5 ULS normally 1.0

Choose a load case in the included load combination. Define partial factor and combination factor for each load case.

Choose a load combination and click the Edit… -button

Edit the parameters in the Editing load -window



35

6 DESIGN -tab

A structures profile type and size, material, service class and reliability class, and also parameters and calculating settings are defined in the DESIGN -tab. Functions in program version 2.4 on this page are divided into: PROFILE SELECTION, DESIGN PARAMETERS and DESIGN RESULTS.

Information in the PROFILE SELECTION -section is shown below:

Information in the List of cross-section sizes -window:

For rectangles: Material Cross-section values(A, Iy, Wy) Shape Spacing c/c Width Weight Height Length Picture of the cross-section For Kerto-Ripa –slabs: Marking Length Top/Bottom plate Weight Ribs Picture of the cross-section

Information of the chosen structure: Profile type Material (only for rectangular cross-sections) Profile size c/c spacing between structures

Information in the lower beam of the page: Structure type Chosen material, profile size, c/c spacing and length OR the Kerto-Ripa –marking



36

Functions in DESIGN PARAMETERS -section and the lower block of the PROFILE SELECTION -section are shown below:

NOTE! Only activated checkboxes are taken into account in the calculation

A note text reminds the user to check all design parameters before finalizing the results

For tapered and sloped beams, measure B (width of the profile) is the only variable parameter in the list of cross-section sizes

Calculating settings and design parameters for the structure:

Choose the service class

Choose the reliability class

From the -button, next to the STRUCTURAL DESIGN, a window for global calculating settings opens.

Corresponding -buttons to settings for ksys -factor, buckling and lateral torsional buckling are available under ULS.

Also, corresponding -buttons to settings for deflection and vibration are available under SLS.

Finding a suitable profile -buttons:

Find first suitable (from the start) , search by calculating the next suitable profile, starting from the beginning of the profile size list.

Find next suitable (forward from the active) , search by calculating the next suitable profile, starting from the next profile in the profile size list.

Buttons Previous and Next selects and calculates previous or next profile in the profile size list.

Find max. spacing , search by calculating the maximum spacing.

Find max. span length , search by calculating the maximum span length.

Arrow buttons decreases/increases values in steps (spacing: 25 mm, span length: 100 mm).



37

Contents of the DESIGN RESULTS -section and other functions in the DESIGN -tab are shown below:

-button shows the following information: characteristic material values (strength- and stiffness-values) specific weight max. force magnitude and position max. and min. support reactions commentaries and additional instructions for materials and design

-button shows all the results in detail

-button shows results for the main parts of the calculations

Design results:

After choosing the cross-section, the design results shows up immediately

Green circle indicates that the chosen cross-section fulfills the corresponding design criteria for this structure

Red circle indicates that the chosen cross-section does not fulfill the corresponding design criteria for this structure

Total utilization rate shows the results rate with respect to deterministic design

NOTE! Width of columns can be adjusted by dragging the yellow vertical lines. This is also possible in other tabs.



38

6.1 Choosing structures to be designed

The choice of designable structures are as follows:

SHAPES OF CROSS-SECTIONS

Rectangle Kerto-Ripa- ribbed slab Kerto-Ripa- box slab Kerto-Ripa- open box slab

MATERIALS

KERTO-S as beam KERTO-Q as beam KERTO-S as plate KERTO-Q as plate, parallel (surface veneers in parallel with the span direction) KERTO-Q as plate, perpendicular (surface veneers perpendicular to the span direction) KERTO-T Re-glued KERTO-S as beam Re-glued KERTO-S as plate KERTO-QP as beam KERTO-QP as plate C14 C18 C24 C30 C35 C40 GL24c GL24h GL30c GL30h Standard posts (GL30c) Chipboard P6 (Service class 1 only) Metsä Wood Spruce plywood parallel (surface veneers in parallel with the span direction) Metsä Wood Spruce-plywood perpendicular (surface veneers perpendicularly to the span direction) Kerto-Kate parallel (surface veneers in parallel with the span direction) Kerto-Kate perpendicular (surface veneers perpendicularly to the span direction)

CROSS-SECTIONS

After choosing the shape of cross-section and material, a list of corresponding cross-sections are read from the database and shown in the DESIGN -tab.

Databases for the cross-sections are found under the main menu, under Databases. Also, look at chapter 10. Managing databases , in this guide.

SERVICE CLASSES

1 2 3 (requires protective treatment)



39

RELIABILITY CLASSES

CC3 (KFI=1.1) Great sanctions for loss of life or very large economic, social or environmental damage

CC2 (KFI=1.0) Significant sanctions for loss of life or significant economic, social or environmental damage

CC1 (KFI=0.9)

Minor sanctions for loss of life or small or insignificant economic, social or environmental damage

Load combinations in the Loading -tab will automatically be updated when the reliability class is changed in the DESIGN -tab.



40

6.2 Designing Kerto-Ripa slabs

Kerto-Ripa ribbed slabs, Kerto-Ripa box slabs, and Kerto-Ripa open box slabs can be designed with the FINNWOOD 2.4 -program version. Slabs design contains the same calculations as the rectangle cross-sections, except for the buckling check and lateral torsional buckling check, because the slabs are assumed to be laterally supported.

Structure type for a slab can be floor-, roof-, or free-structure. The use of Kerto-Ripa element as a column structure is blocked.

Design of the Kerto-Ripa –slab is performed for one rib-lane at a time. The structural designer must ensure the suitability of all ribs in the slab. Below is shown an example of a box slab, where the edge rib is determinative in the stress calculation.

Kerto-Ripa –laattojen poikkileikkausten nimet on määritetty seuraavasti:

The dimensioning of Kerto-Ripa elements is carried out according to European Technical Approval (ETA-07/0029) and its design guideline. Below some of the guidelines:

- ksys-factor is not taken into account

- Possible holes and openings are to be verified separately

- Supports pressure measurements are determined in this manual, chapter 3.3 Kerto-Ripa slabs, defining the end supports. Other supporting cases must be checked separately.

Determinative rib-lane for the design is shown in yellow in the cross-section picture.

Identifier: R – rib slab, H – box slab or open box slab Examples: R250-2500x25-5(1)x51x225

H275-2500x25-5(1)x51x225-2500x25 H275-2500x31-5(1)x51x200-150/300x43

Information from left to right: total height [mm] top slab, total width [mm], recommended widths 1800 mm and max. 2500 mm top slab, sanded thickness [mm] number of ribs (designed rib in parenthesis) width of ribs [mm] height of ribs [mm] Additional information for the box slab bottom slab, total width [mm], recommended widths 1800 mm and max. 2500 mm bottom slab, sanded thickness [mm] Additional information for the open box slab bottom flange, total width [mm], recommended width, edge/intermediate ribs 150/300 mm bottom flanges, sanded thickness [mm]



41

- Finnwood calculates the share of surface loads affecting the rib, based on the slabs geometry. Point loads and line loads are presumed to fully load the rib.

- Kerto-Ripa –elements are built from Metsä Wood products, see table below. Top slabs and bottom slabs are sanded both sides (1 mm/side = total of 2 mm) before gluing.

Elements part Material Usage in element Ribs Kerto-S All element types Top slab Kerto-Q All element types Bottom slab Kerto-Q Box slabs Bottom flanges Kerto-S Open box slabs

NOTE! In the Finnwood 2.4 version, for Kerto-Ripa box slabs, it is possible to choose a non-structurally glued wood board for the top slab, instead of the Kerto-Q plate. If this is the case, then the top slab does not function as a part of the cross-section. However, the calculation will use materials self-weight to be at a value of 5.0 kN/m3 .

A rib-lane design for the Kerto-Ripa –element does not check the top slab for bending stability, shear stability, and deflection perpendicularly to the ribs direction. These designs can be made with Finnwood 2.4 as follows:

- A structurally glued top slab for Kerto-Ripa -element is modelled with hinged supports, if the top slab has a multi-span structure. Deflection for a structurally glued top slab, between two ribs, can be reduced by 23 %, if it is stressed with a uniformly distributed load, it is hinge supported and the max distance is 600 mm between two ribs, which are structurally connected from their lower surfaces.

- Choose a default design structure that corresponds to the dimensioning situation, either Floor beam/slab or Roof beam/slab .

- In the MODEL -tab, define the parts of the structures span-, and support-measures, so that they match the ribs spacing and width. Use the width of the structures cross-section as the load width.

- In the LOADING -tab, check that the loads corresponds to the actual situation.

- In the DESIGN -tab, choose Kerto-Q as plate, perpendicular for material. Remember, that the surface veneers of a Kerto-Q top slab are perpendicular with respect to the elements span-lengths direction. NOTE! Kerto-Q plates nominal thickness without sanding (e.g. 27 mm) is used for the elements top slab when designing it perpendicularly to the span-lengths direction.

- Check service class, reliability class and design settings.

- NOTE! The top slab must also cover the 0.5 mm criteria of deflection in the vibration calculation, when the element is used on ground floors or compartment floors. If the Kerto-Ripa element is not coated with other load sharing layers (e.g. impact sound insulation and floating floor structure), the deflection criteria is fulfilled, if the thickness of the elements top slab is t ≥ s / 25 , ribs spacing distance c/c divided by 25. For example, a perpendicular computational thickness of 27 mm for a Kerto-Q top slab gives s ≤ 675 mm c/c spacing distance between two ribs.

- NOTE! For Kerto-Ripa roof elements, its top slabs perpendicular max. deflection cannot exceed wfin ≤ L/150 , if deflection is not restricted by any other design criteria.

- The total utilization rate and other design results are shown in the DESIGN -tab and the PRINTOUTS -tab

- Save the calculation.



42

6.3 Material values and notes in the design

MATERIAL VALUES

Material values used in FINNWOOD 2.4 are established from the following sources:

- Kerto-T, VTT certificate VTT-C-1781-21-07

- Kerto-S and Kerto-Q, VTT certificate Nr 184/03 and VTT statement VTT-S-05218-08

- Kerto-Ripa –slabs, European technical approval ETA-07/0029 and its separate design guide (part A)

- Kerto-S multiple glued, VTT certificate VTT-C-1588-21-07

- Kerto-QP, VTT statement VTT-S-05156-11

- Standard columns, standard EN 14080:2013

- Glulam, standard EN 14080:2013

- Sawn timber, standard EN 338:2016

- Chipboard P6, standard EN 12369-1

- Metsä Wood Spruce plywood, VTT certificate Nr 4-95 (2008)

- Kerto-Kate, VTT certificate VTT-C-4457-21-09

NOTES ABOUT THE DESIGN

Metsä Wood Spruce plywood products

Material values used with Metsä Wood Spruce plywood products are sanded thicknesses. Also, design calculations are executed using these sanded thicknesses (sanded thickness = nominal thickness -0.5 mm ). However, only nominal sizes are shown in the printouts. In other words, design calculations are suitable for both sanded and nominal thicknesses.

Finnwood’s design calculations are also suitable for special spruce plywood products, such as Metsä Wood Spruce weather Guard and Metsä Wood Spruce Fire Resist.

Designing holes and cuttings (ULS)

For Kerto® products as beams (Kerto-S, Kerto-Q, multiple glued Kerto-S and Kerto-QP), holes are calculated according to VTT certificate Nr 184/03 appendix A . Hole calculations for Kerto-QP products are executed in the same manner as for Kerto-S products. Cuttings calculations for Kerto®-, sawn timber-, and glulam-products are executed according to RIL 205-1-2017.

Designing support pressure (ULS)

Measures for support lengths are limited between 20…500 mm.

Support pressure design is not included for plate structures: ”Metsä Wood Spruce plywood”, ”Chipboard P6” and ”Kerto-Kate”.



43

Sloped roofs/slabs

For sloped roof beams or roof slabs, the normal force loads center of gravity is assumed to join to the neutral axis of a structures part. In this case, the eccentricity of the normal force load must be separately taken into account.

A possible eccentricity from a normal force load can be taken into account with point load + bending moment -load combinations, alias moving the normal force to the neutral axis and adding the ensued bending moment as a separate load.

Columns

It is not possible to use Kerto-Ripa –elements and plate structures (”Metsä Wood Spruce plywood”, ”Chipboard P6” and ”Kerto-Kate”) as column structures.

Deflection check (SLS)

Deflections for cantilevers and span-lengths measuring a length of less than 200 mm are ignored. Deflections of these structures are calculated, but the utilization rate is set to 0 % .

Also, if the upward deflection of a cantilever is less than 20 mm, it will be ignored.

Vibration check (SLS)

Vibration check does not include the checking of additional deflection caused by the 1 kN point force on floor plates resting on the structure. Floor plate thickness must be chosen by the structure designer in a way, that the guidelines for the plate thickness is fulfilled. See chapter 6.9.2 : Vibration check instructions.

Floor plates included in the vibration check (e.g. floating floor structures and partition loads) must be separately designed considering self-weight and imposed load.

See also:

6.4 General design settings

6.5 General settings for ultimate limit state

6.6 Buckling settings

6.7 Lateral torsional buckling settings

6.8 Deflection settings

6.9 Vibration settings

10 Managing cross-section databases



44

6.4 General calculation settings

General calculation settings used in FINNWOOD 2.4 can be edited by selecting Settings > Calculation settings… from

the main menu. These settings also appear by pressing the -button located next to the STRUCTURAL DESIGN text in the DESIGN PARAMETERS -section under the DESIGN -tab. Contents of this window is shown below.

CONSIDERATIONS CONCERNING THE CALCULATION SETTINGS

- Only activated checkboxes in the DESIGN -tab are taken into account in the calculation.

- Default values in FINNWOOD 2.4 for all structures are as shown in the picture above.

- If the user changes general calculation settings and accepts by pressing the OK -button, the DESIGN -tab will show for the user to check other settings.

- For plate structures, always pay attention to shear deflection when calculating deflections. These are: ”Kerto-Q as plate parallel”, ”Kerto-Q as plate perpendicular”, ”Metsä Wood Spruce plywood parallel”, ”Metsä Wood Spruce plywood perpendicular”, ”Kerto-Kate parallel” and ”Kerto-Kate perpendicular”.

- The automatically added self-weight for a Kerto-Ripa –slab consists only of the calculated rib-lane (kN/m). The whole weight of the element (kg/m2), shown in DESIGN -, and PRINTOUTS -tab includes also the weight of additional perpendicular parts. Weight of Perpendicular parts are estimated to be 10 % of the elements total weight.

Editable calculation settings: Shear deflection is taken into account when calculating deflections Shear deflection is taken into account when calculating forces Self-weight of structure is automatically taken into account (as permanent load) Reduction of shear force is taken into account close to supports NOTE ! More info about reduction of shear force in the Info -tab.



45

- Reduction of shear force close to supports is done as follows:

- Loads are assumed to affect the opposite side of the structural parts support face.

- Reduction is performed on the shear force curve of the load combinations.

- A measure of 0.9xH, from the edge of both supports, will be ignored from the shear force diagram, except when a point load is applied in this area. In the case of a point load in this area, the shear force diagram is linearly reduced.

- To eliminate the effect from the self-weight, a reduction measure of 0.9xH from the edge of the support is used. Parameter H is the height of the cross-section, or the height of the Kerto-Ripa elements rib.

- Reduction of shear force can only be done for middle-, or intermediate -supports in continuous Kerto-Ripa elements.



46

6.5 Ultimate limit state ULS, general settings

In the DESIGN PARAMETERS -section, the -button next to the ULS text opens a window, where the system strength factor ksys is defined. This factor defines the distribution ability of loads to parallel structures.

Options to values for the factor and terms of their use is explained in the window, see below. Default value for all pre-defined structures is ksys = 1.0.



47

6.6 Buckling check ULS, settings

Buckling check settings for ULS are defined from the -button next to the Buckling check text. This window is shown below:

Guidelines for defining buckling parameters

Buckling length Lc of a compressed rod is depended of how the structure is supported. RIL 205-1-2017 Puurakenteiden suunnitteluohje, Table 6.1S ( Design of wooden structures) and Suomen Rakentamismääräyskokoelma, B10 Puurakenteet 2001, Table 5.4 ( Finnish construction code collection ) gives guidelines to defining the buckling length, where L is the length of the element.

Lc Supporting types 0,7 L Element is rigidly fixed from both ends 0,85 L Element is rigidly fixed from one end and the other end is pinned 1,0 L Element is pinned from both ends 1,0 a Element is transversally supported along the buckling direction, spacing measure a 1,5 L Element is rigidly fixed from one end and the other end is attached to its direction, but not to its position 2,5 L Element is rigidly fixed from one end the other end is free to move laterally

Buckling directions are with respect to the local coordinate system of the structure z-direction is the structures vertical axis y-direction is the structures side axis

Tick the check boxes that corresponds to wanted buckling direction

The Info –page provides more information about defining buckling lengths

Buckling length options: Buckling length based on a factor and

distance between supports, e.g. Lc = 1.0 x L

or Buckling length [mm] based on

support spacing, that is used for all supports and cantilevers along the whole length of the structure part



48

6.7 Lateral torsional buckling check ULS, settings

Lateral torsional buckling check settings for ULS are defined from the -button next to the Lateral torsional buckling check text. This window is shown below:

NOTE! These calculation settings for lateral torsional buckling only apply to bending around the y-axis, My. FINNWOOD 2.4 does not calculate lateral torsional buckling for bending around the z-axis, Mz.

Options for side supports:

Spacing between supports preventing lateral torsional buckling Lk1 / Lk2 [mm] Spacing is equal to main support’s spacing Structure is fully supported on the top face

As an example of the first alternative is boarding or transverse battening with a spacing equal to the support spacing for the lateral torsional buckling.

NOTE! Only one set of Lk1 and Lk2 values can be assigned for each structure part.

NOTE! Side supports must be able to transfer the load, caused by lateral torsional buckling, to rigid structures. In other words, side supports must be attach to a point on the rigid structure.

Upper side supports of the structure part:

Upper side supports are needed, if the structures top face is under compressive stress ( My > 0)

Example: top face of a single span beam, at the middle

Lower side supports of the structure part: Lower side supports are needed. if the structures bottom face is under compressive stress (My < 0) Example: continuous beams, intermediate supports and in the vicinity

Choices: Effective torsional buckling length and multiple cross-sections These parameters are only valid for rectangle cross-sections



49

According to RIL 205-1-2017, the position of a determinative load on a rectangular cross-section affects the effective torsional buckling length, by increasing it (by the term 2xH) or by decreasing it (by the term -0,5xH).

The default setting for the effective torsional buckling length is shown below. This setting indicates, that the load is on the neutral axis, or that the compressed face of the structure is only stressed with point loads directly on the torsional buckling supports.

The list of all settings (the highlighted setting is the default setting):

Structures with different settings for the effective torsional buckling length is shown below in corresponding order (numbered 1-6) :

1 – Lef1 = Lk1 and Lef2 = Lk2

Example: single span beam, load is on the neutral axis

2 – Lef1 = Lk1+2xH and Lef2 = Lk2

Example: single span beam, load is on the top face, the compressed face, 2xH-term is considered, when My>0

3 – Lef1 = Lk1 and Lef2 = Lk2+2xH

Example: single span beam with cantilever, load is at the bottom face, pulled face, 2xH-term is considered when My<0



50

4 – Lef1 = Lk1+2xH and Lef2 = Lk2+2xH

Example: beam with two spans, load is on the top face (1st span) and at the bottom face (2nd span)

Load is on both the compressed-, and tensile -faces of the structure, along the two spans. The load causes a positive field moment on the first span in the structures compressed face and on the second span in the structures pulled face. The supports causes a negative moment on the first span in the structures pulled face and on the second span in the structures compressed face. 2xH -term is considered in both spans when My>0 and My<0.

5 – Lef1 = Lk1+2xH and Lef2 = Lk2-0,5xH

Example: beam with two spans, load is on the top face. Pulled face at the intermediate support and nearby. Compressed face on the rest of the structure. Both terms, (2xH and -0.5xH) are considered.

6 – Lef1 = Lk1-0,5xH and Lef2 = Lk2+2xH

Example: beam with two spans, load is at the bottom face. Compressed face at the intermediate support and nearby. Pulled face on the rest of the structure. Both terms (2xH and -0.5xH) are considered.



51

6.7.1 Torsional buckling settings for a free structure

Supporting options for a free structure:

- Spacing c/c between supports preventing torsional buckling Lk1 / Lk2 [mm] - Main supports spacing for the structure - Structure part is fully supported against torsional buckling - Lk1 / Lk2 equals to the side- / main- supports spacing

The last choice of the above options are defined based on the structures upper-, and lower- supports. More information about defining side supports can be found from chapter 3.2 Geometry and supporting methods for a free structure. Otherwise, the free structure settings are the same as for the predefined structures.



52

6.8 Deflection check SLS, settings

Deflection check settings for SLS are defined from the -button next to the Deflection check text. This window is shown below:

In FINNWOOD 2.4, the default values for deflection limits concerning main girders, cantilevers and secondary girders are according to table 7.2 in RIL 205-1-2017 .

These values are also shown in the adjacent table to the right.

is the span 1) Applies to floors only 2) Applies to linear or pre-cambered structures, but not to curved or folded brackets between support points 3) Applies to pre-cambered structures and to curved or folded brackets between support points

Deflection limiting criteria: Every deflection criteria can consist of a relative or/and an absolute deflection limit Relative deflection limit refers to the relationship between span length and a defined value, e.g. L/300 Absolute deflection limit refers to a max. value of the deflection, e.g. 12 mm ”- -” indicates no limiting criteria

Deflection limits for cantilevers are set by multiplying the relative deflection limit with a factor.

Deflection in the structures z-direction can be limited with 6 different criteria: Wq,inst Momentary deflection caused by variable loads Wq,fin Final deflection caused by variable loads (incl. creep) Wfin Final deflection caused by sum of loads (incl. creep and precamber) Winst Momentary deflection caused by sum of loads Wg, inst Momentary deflection caused by static loads Wnet, fin Final deflection caused by sum of loads (incl. creep)

The Info -tab show guidelines about defining deflection limits.

Picture 7.1 from RIL 205-1-2017 is shown in the window to clarify the variables.

A precamber, Wc, can be set at the mid-point for a single span structure.

NOTE! In this case, a deflection criteria Wfin and its limiting value must be added.



53

6.9 Vibration check SLS, settings

Parameters for the vibration design are defined in this window. Vibration check is calculated according to chapter 7.3 in RIL 205-1-2017. In addition, FINNWOOD 2.4 also calculates cantilevers and deflections caused by point loads in continuous floor beams. See chapter 6.9.2 vibration check, the info page.

Vibration check settings in SLS for rectangular cross-sections are defined from the -button next to the Vibration check text. This window is shown below. The first tab is for parameters and the second tab (Info) consists of explanations for them.

Vibration settings windows are different for Kerto-Ripa –ribbed slabs, –box slabs and –open box slabs, as follows:

- ”Floor plate / structure above the beam”- and ”Composite action”-options are not included, because Kerto-Q top slab is included in the floor structure. This is automatically included in the calculation.

- ”Transverse bracing lines”-option is not included, because during manufacturing, transverse bracings are always installed into the Kerto-Ripa slab. This is automatically included in the calculation.

- ”Cross battens underneath the floor beams”-option is not included for the slabs.

Rectangular cross-sections

Ribbed-, and open box- slab

Box slab



54

6.9.1 Design principles for vibration checks

In RIL 205-1-2017, vibration design criteria for floor structures in residential and office apartments are accordingly:

- Lowest fundamental frequency f1 > 9 Hz - Floors max momentary deflection at the floor beam caused by a static point force of 1 kN must be δ ≤ 0.5mm

In small rooms, the 0.5 mm deflection can be raised by a factor k, according to RIL 205-1-2017 picture 7.2

Floors continuity, with or without cantilevers, is considered in FINNWOOD 2.4 by using equivalent spacing for the formula 7.6-FI in RIL 205-1-2017, as follows :

- End spans 0,90xL - internal 0,82xL

A floor span adjacent to a cantilever is considered as an end span.

Vibration design for cantilevers in FINNWOOD 2.4 are calculated as follows:

- Minimum fundamental frequency and deflection caused by a point force for a single-span beam with either one cantilever or two cantilevers, is calculated according to VTT’s research report No. VTT-S-03733-08 (VTT = Technical Research Center of Finland ).

- Minimum fundamental frequency for a continuous multi-span beam with one or two cantilevers, having equal or not equal span distances, is calculated as follows:

- Cantilever and the span next to it (alias cantilever beam) are calculated as a uniform structure

- Other spans are considered as separate single span structures

- Fundamental vibration values for every span and cantilever are received from the calculation.

- The smallest value is the value for the whole structure.

- In case of a point load at the free end of a cantilever, causing deflection which must be calculated, the transverse stiffness of the structure in the adjacent span is taken into account, if the cantilever is considered as a beam.

- The adjacent span next to the cantilever can be supported from either two, or four sides. The calculated deflection value is at least equal to the deflection of the rigid stem of the cantilever.

- If an area exposed to walking on a cantilever floor structure does not reach the end of the cantilever, the unloaded length can be ignored. Deflection and lowest fundamental frequency is in this case calculated using the shortened length of the cantilever.

- If an area exposed to walking on a cantilever floor structure does not reach the end of the cantilever, the unloaded length can be ignored. Deflection and lowest fundamental frequency is in this case calculated using the shortened length of the cantilever.

- Vibration is not done for cantilevers with a length less than 200 mm.



55

6.9.2 The Info page for vibration check

The Info -tab, in the Vibration check window, gives explanations to parameters for the vibration check, as following.

Mass per unit area [kg/m2]:

Combined mass of the floor weight, partition wall weight and the long-term effect of the imposed load per unit area in kg/m2. The long-term effect of the imposed load is taken as 30 kg/m2. The mass value is automatically obtained from the input values of the Wizard of loading model window of the Loading tab sheet, and from the setting of the self-weight of the beam defined in the Calculation settings window of the Settings menu.

The result is shown in the vibration design results of the Design tab sheet (please click on the “info” button), and in the vibration settings of the Printouts tab sheet.

The mass per unit area can be manually defined when the floor beam/slab is converted to a free structure.

Continuous floor beams:

The continuity of floor beams is taken into account by using equivalent floor spans in the formula (7.6-FI) of the Design Instructions RIL 205-1-2017 as follows:

- End spans 0,90xL - Internal spans 0,82xL

NOTE! A floor span adjacent to a cantilever is considered an end span.

Vibration check of cantilevers:

The minimum fundamental frequency and the deflection under 1 kN concentrated load of a single span beam with one or two cantilevers are calculated according to the VTT Research Report No. VTT-S-03733-08.

The minimum fundamental frequency of a continuous multi-span beam with one or two cantilevers and with equal or unequal span lengths is calculated as follows:

- A cantilever and the end span next to it are calculated as a uniform beam

- Other spans are checked separately as single span structures

- The fundamental frequency is shown for each span or for the end span and cantilever

- The fundamental frequency of the whole structure is the minimum of the calculated frequency values

The deflection under 1 kN concentrated load is calculated by taking into account the transverse stiffness of the adjacent floor span, when the cantilever is considered a beam structure. The adjacent span can be supported either at two or at all four edges. The calculated deflection must be equal to the deflection of a cantilever with a rigid support, at the minimum

Location of the rib (concerns only Kerto-Ripa® elements):

The location of the rib in a Kerto-Ripa element affects the magnitude of the vertical concentrated static force F used in the deflection check. These checks are carried out as follows (magnitude of the force in parentheses):

a) Middle rib of an element (1.0 kN) b) Edge rib of an element at the joint of two connected elements (0.6 kN) c) Edge rib of an element at the free edge, no adjacent element (0.5 kN)

In case a), the transverse stiffness of the floor structure (EI)B is calculated as the sum of the transverse stiffness of the transverse bracings (i.e. blockings), slab(s) and the floating structure. In case b), the transverse stiffness of the floor structure (EI)B is calculated as follows:

- Kerto-Ripa ribbed and open box slabs: as the sum of the transverse stiffness of the floating floor, top slab and the transverse bracings, provided that the transverse bracings and the bottom of the ribs have been connected to a



56

continuous tension board over the joint - Kerto-Ripa box slabs: as the sum of the transverse stiffness of the floating floor (100 %), and 10 % of the

combined transverse stiffness of the transverse bracings and the box slab In case c), a Kerto-Ripa element can share loading only in the direction of the middle rib(s), in which case only 10 % of the total transverse stiffness of the floor structure can be taken into account. Largest dimension of the room L [m]: L is the largest dimension of the room above. This parameter affects the deflection criteria of the vibration check. Floor width B [m]: B is the width of the floor structure (i.e. the span length) in the transverse direction of the floor. The floor can be assumed supported at all four edges when the supports in the transverse direction B are e.g. the following: Intermediate or gable wall which is attached to the floor structure without any flexibility, and to which the edge beam of the floor, cross battens or floor plates are attached. Support condition: The support condition of the floor affects the calculation of the minimum fundamental frequency. Alternatives: Supported at 2 edges (a one-way load-bearing floor structure) Supported at 4 edges (a two-way load-bearing floor structure) NOTE! When checking the edge ribs of Kerto-Ripa elements that are free (no adjacent element), the structure is automatically assumed to be supported at two edges only. The same support condition must be used when checking the other ribs of the same Kerto-Ripa element (i.e. the middle ribs or the edge ribs in the joint of two elements). Reduction of cantilever's length [mm]: For cantilevers, it is possible to define a length at the cantilever's free end which has no imposed load acting on it. The reduced length of the cantilever is used in the calculation of deflection and fundamental frequency. Vibration is not checked with cantilevers shorter than 200 mm. Transverse bracing lines: Blockings which are used as transverse bracing lines are of the same material and size as the beams. It is also assumed in the calculations that the blockings are connected to a tension chord (made of 22x100 sawn timber at the minimum) at the bottom edge by nails 2.8x75 c/c 200 (minimum). Similarly, the blockings are connected to the floor plate at the top by nails 2.8x75 c/c 200 (minimum). In the calculations, the floor plate is replaced by a compression chord (made of 22x100 sawn timber at the minimum) so that a symmetric cross-section can be used in the calculations. Both the tension and compression chords are nailed to the beams with the same nails (2 nails 2.8x75 per beam). Alternatives: No transverse bracing lines 1 bracing line/span 2 bracing lines/span 3 bracing lines/span Instructions on the location of the transverse bracing lines have been presented in the Appendix B of the Design Instructions RIL 205-1-2017 (see Figure B.4.2). These are the following: Transverse bracings of Kerto-Ripa elements: In all Kerto-Ripa elements, the transverse bracings (i.e. blockings) shall be made of the same Kerto-S size as the ribs of the slabs. In Kerto-Ripa ribbed slabs, blockings are connected to the top slab and to a tension chord (made of 22x100 C18 sawn timber minimum) at the bottom of the element by nails 2.8x75 c/c 200 (minimum). The tension chord is also nailed to the ribs of the element with the same nails (2 nails 2.8 x75 per rib). In Kerto-Ripa open box slabs, blockings are connected to the top and bottom slabs of the element by nails 2.8x75 c/c 200 (minimum). The tension chord (made of 22x100 C18 sawn timber minimum) is then connected to the bottom of the bottom



57

slab at the ribs with the same nails (2 nails 2.8 x75 per rib). In Kerto-Ripa box slabs, the blockings will be assembled during the manufacturing of the elements. When the span length L of the slab is 8 m or smaller (L≤8 m), one blocking line will be assembled in the mid-span. When the span length is greater than 8 m (L>8m), three blocking lines will be assembled approximately at the quartiles of the span length. Floor plate / structure above the beam: The stiffness of the floor structure is increased in both directions when the floor plate (on top of the beams) is attached to the beams. It is assumed that the longitudinal direction of the plates (i.e. the assembly direction) is perpendicular to the longitudinal direction of the load-bearing beams. When tongue-and-groove planking is used and the planking is assembled and attached to the beams perpendicular the longitudinal direction of the load-bearing beams, the stiffness of the floor structure is increased in the longitudinal direction of the planking only. The additional deflection of the floor plate (or floating floor structure) from the 1 kN load shall be less than 0,5 mm. This criterion is fulfilled, for instance, when the following plate thicknesses are used: plywood or Kerto-Q t ≥ s/25, chipboard t ≥ s/20, where t is the plate thickness (mm) and s is the spacing of beams (mm). With tongue-and-groove planking, the deflection of each board is checked as continuous structure. NOTE! Floor plates or tongue-and-groove planking shall be separately designed for the loads coming from the floating structures. Alternatives: Not taken into account Chipboard 22 mm (EN 312-6) Spruce plywood 15 mm Spruce plywood 18 mm Spruce plywood 21 mm Kerto-Q 24 mm Kerto-Q 27 mm Kerto-Q 33 mm Kerto-Q 39 mm Kerto-Q 45 mm Kerto-Q 51 mm Kerto-Q 57 mm Kerto-Q 63 mm Kerto-Q 69 mm Tongue-and-groove planking 28x95 C18 Composite action: The floor plate (on top of the beam) can be attached to the beams by nails, or by nails and gluing. There are two alternatives for gluing: on site or in a factory (i.e. structural gluing). Composite action can be utilized in the calculations depending on the connection type between the plate and the beam. Alternatives: No composite action Floor plate acts as an independent structure in both directions Gluing on site 50 % of the composite action between the plate and the beam is taken into account Structural gluing Full composite action is assumed between the plate and the beam NOTE! Composite action cannot be taken into account when tongue-and-groove planking is used. Nor are the alternatives for composite action shown for structurally glued Kerto-Ripa elements. Floating structure / cross battens + plate: The stiffness of the structures below can be taken into account in both directions of the floor, provided that the floating structure is continuous in both directions (no construction joints). The floating structure is assumed to be completely unconnected to the beam (no composite action). The material values of C18 sawn timber have been used in the calculations for the cross battens and the cross-section sizes presented are in the following order: ”BxH” i.e. ”width x height” (mm). Alternatives:



58

No floating structure Screed 40 mm (C20) Screed 50 mm (C20) Screed 60 mm (C20) Screed 70 mm (C20) Screed 80 mm (C20) 18 mm floor plate (E=4000 N/mm2) 22 mm floor plate (E=4000 N/mm2) 47x98 c/c 400 + 2x15 mm gypsum floor plate (E=3500 N/mm2) 95x24 c/c 300 + 2x15 mm gypsum floor plate (E=3500 N/mm2) 98x47 c/c 400 + 2x15 mm gypsum floor plate (E=3500 N/mm2) 100x22 c/c 300 + 2x15 mm gypsum floor plate (E=3500 N/mm2) 100x32 c/c 300 + 2x15 mm gypsum floor plate (E=3500 N/mm2) 47x98 c/c 400 + 22 mm chipboard for floors 95x24 c/c 300 + 22 mm chipboard for floors 98x47 c/c 400 + 22 mm chipboard for floors 100x22 c/c 300 + 22 mm chipboard for floors 100x32 c/c 300 + 22 mm chipboard for floors 95x24 c/c 300 + 15 mm spruce plywood 100x22 c/c 300 + 15 mm spruce plywood 100x32 c/c 300 + 15 mm spruce plywood Cross battens underneath the floor beams: The structures listed below can be taken into account in the transverse stiffness of the floor. The material values of C18 sawn timber have been used in the calculations and the cross-section sizes presented are in the following order: ”BxH” i.e. ”width x height” (mm). Alternatives: No cross battens 45x45 c/c 300 45x45 c/c 400 45x45 c/c 600 48x32 c/c 300 48x32 c/c 400 48x32 c/c 600 48x48 c/c 300 48x48 c/c 400 48x48 c/c 600 95x24 c/c 300 95x24 c/c 400 95x24 c/c 600 100x22 c/c 300 100x22 c/c 400 100x22 c/c 600



59

7 Fire/accidental design

Fire/accidental design is included in FINNWOOD 2.4 . Settings are defined in the FIRE/ACCIDENTAL DESIGN -section under the DESIGN -tab.

7.1 Settings for fire/accidental design

7.1.1 Defining the structure and the fire protection

Settings for expected resistance time, fire design type and fire protection are defined from the -button next to the FIRE/ACCIDENTAL DESIGN text.



60

- Expected resistance time t

- Location of fire

- Fire design type

- Fire protection



61

7.1.2 Stability settings

If the structure in a fire/accidental design is assumed to use the same stability properties as for normal conditions, these settings can be copied to the fire/accidental design from the design settings window for normal conditions.

If stability properties for fire/accident are used, they are defined in the fire/accident design settings window:

Deflection limits includes the allowed deflection criteria values (relative/absolute):

7.2 Fire state calculations

Given values and factors to a fire design in Finnwood:

- fik (strength-, and stiffness -factor for a 20% fractile calculation)

- 0β (one-dimensional charring rate) and

nβ (multi-dimensional charring rate)

- 2k (isolation factor before the fire protection fails),

3k (isolation factor after the fire protection fails), cht (starting

time of charring), ft (starting time when the fire protection fails) and

at (ending time of accelerated charring)

-

0k (factor to calculate properties of the zero-strength layer at time t)

- 0d (zero-strength layer)



62

- nk (factor to convert an irregularly charred residual cross-section into a nominal rectangular cross-section)

-

sk (this factor adjusts how much the fire impact is greater for narrow cross-sections compared to wider cross-sections)

-

fikmod,and

fiEk ,mod,(strength-, and stiffness -factors under fire)

With the settings mentioned above, Finnwood calculates the following values:

- residual cross-section

- strength and stiffness

- stability

- deformations

Values can be viewed in the DESIGN –tab:

NOTE! If a fire/accidental design is made for the structure, their results are shown in the PRINTOUTS -tab (See chapter 9):



63

8 Additional results -tab

Structures bending moments-, shear force-, and deflection -curves are presented in the Additional results -tab. Also, support reactions for a load group or load combination are illustrated here. Normal force -curves for compressed structures (sloped ”roof beam/slab” or ”column”) are also illustrated.



64

9 PRINTOUTS -tab

Structures calculated results are shown in the PRINTOUTS -tab. These results can be saved to a file, or printed out. The tab is described below.

Presentation of the calculation printout: Extensive printing format displays all calculation results The short form of printing only shows the details of extreme values You can add/remove the data output by ticking/unticking cases

Printing buttons: Print preview… -button brings up the preview of the print Save to PDF… -button saves the printout to a pdf file Project information… -button opens up the project information window Font of the text… -button lets You choose a font for the printout

This view shows the contents of the printout



65

9.1 Information in the printouts

The printout contains the following information.

- Program version

- Project information

Designer, company, name/position, project name, customer, additional information and instructions of the structure part.

- Structure information

Structure type, material, cross-section, service class, reliability class, spacing/load width, dimensions and supporting of the structure, material values, partial factor, kmod-, and kdef-factors.

Different sizes, amounts and materials of parts for the Kerto-Ripa –element, effective stiffness (EIef,MRT and EIef,KRT) and estimated weight for the element.

As new information, the printouts in FINNWOOD FI 2.4 show values for A, Iy and Wy of rectangular cross-sections and the volume weight (for the calculation of the self-weight).

- Load information

In FINNWOOD FI 2.4 , the snow load information is refined with a note added to the end of the output:

- Load combinations

If a load case in the defined load combination for a ready structure is zero (e.g. wind load), it will not be displayed in the PRINTOUTS -tab.

The time class information for each load combination is automatically displayed in the PRINTOUTS -tab in such a way, that it corresponds to the real load cases of the load combination.

- Design information

Design standards, total utilization rate, design parameters, design settings for the vibration, extreme values of the design, extreme values for load combinations and values for extreme forces.

A common header called ADDITIONAL DESIGN RESULTS shows the design results for holes and hinges:

- Support reactions

MRTmax, MRTmin, KRTmax, KRTmin and support reactions for every load group (characteristic values).

For Finnwood 2.4 , new supporting options are available for side supports between structures. Side supporting reactions are shown, if sideway loads are stressing the structure.

- Notes

Under the NOTES -heading, additional and clarifying notes for dimensioning results are shown.



66

9.2 Content in PRINTOUTS

Similar data is shown in the printout file ( e.g. *.PDF ) as in the PRINTOUTS-tab (see chapter 9.1 Information in the printouts) and additionally:

- Copyright text

- At the beginning of the printout is a notification. The calculated length used in the program is not the final order length of the structure:

The following member analysis is only valid for the engineering data below. The actual length of the structural might be different to the engineering length shown.

- Picture of the coordinate system

- Cross-section of the structure

- Structural information and loading information

- At the end of the printout there is a note that the calculations do not take into account loads or moisture conditions during construction. A disclaimer about the validity of the calculations is also shown, which is not allowed to be removed from the printout.

These calculations do not take into account loads or moisture conditions during construction. The need for bracing during construction has to be checked separately. The overall stability of the building, and horizontal forces caused by it, have not been considered. The building designer, main structural engineer or other person responsible for structural behaviour of the whole building has to check separately the applicability of the structural member (beam, column) to the building. The calculations and the printouts made with the Finnwood software are only valid with the Metsäliitto Cooperative (Metsä Wood) products included in the Finnwood software. These products have to be identified on the construction site if requested. Metsäliitto Cooperative (Metsä Wood) or its subsidiaries shall not have any liability to you third parties for products of third party manufacturers or for using such products in the Software or any direct indirect damages or any other damages or losses relating to the products of third party manufacturers or thereof in the Software. Removing these sentences from the printouts is prohibited.



67

10 Managing the cross-section databases

There is a cross-section database for every material in FINNWOOD 2.4. You can read and modify the databases by choosing Databases from the main menu:

- Rectangular cross-sections Suorakaidepoikkileikkaukset…

- Kerto-Ripa –ribbed slabs…

- Kerto-Ripa –box slabs…

- Kerto-Ripa –open box slabs…

All the rectangular cross-sections are shown in a common Database of rectangular cross-sections-window. Every Kerto-Ripa element type has its own database-window.

The content of rectangular cross-section databases are explained in chapter 10.1 and databases for Kerto-Ripa -elements are explained in chapter 10.2 .



68

10.1 Databases for rectangular cross-sections

All rectangular cross-sections are listed in the Database of rectangular cross-sections-window. The most important functions are shown below.

Choosing the database: The name of the active database is indicated in the button This button opens the Choose active database -window, from where You can change the active database by choosing the wanted material from the list

Modify or make a new cross-section by filling in these properties: Name of the cross-section Shape of the cross-section, the amount of cross-sections side by side in parenthesis (1-3 pcs) B [mm], cross-section width H [mm], cross-section height

Cross-section assortment: Tick the cross-section You want to use in the design As default, all cross-sections are chosen Choose all sizes / Remove all ticks –button adds or removes all ticks

Sorting rules of the cross-section list: First width, then height First height, then width

Combining databases: Upper button combines user defined cross-sections into the active database The amount of cross-sections that were added / removed from the database are shown to the user NOTE! It is only possible to add allowed cross-section sizes into the active database

Restore the default cross-section list of the active database: The lower button restores the default cross-section list of the active database

Add -button adds the new/active cross-section to the database Update -button updates the selected cross-section with the active information Remove -button removes the selected cross-section from the database



69

10.2 Cross-section databases for Kerto-Ripa –slabs

Modifying databases for Kerto-Ripa -ribbed slabs, -box slabs and -open box slabs are done in a similar manner as for rectangular cross-section databases (see chapter 10.1). An illustration of a Kerto-Ripa –slab database window is shown below.

Additional parameters for the box slab and an illustrated picture of the structure:

Order of the database: First total height, then total width First total width, then total height First web height, then web width First web width, then web height Designed web number

A view, according to input parameters or a picture in scale of the active slab can be chosen in the database window.

Information about the new/modified cross-section: Name Web beam info (material, number of beams, designed web, measures H1, B1, B2 and B3) Top plate info (material, measures T1, B, B11, B12, B13 and B14) Bottom plate info for box slabs and open box slabs (material, measure T2, measures B21 and B22, or measures B21, B22, B31 and B32)

A new Info -page is added to the FINNWOOD 2.4 –program version. Notes and instructions about choosing parameters for the Kerto-Ripa element are gathered here.



70

Additional parameters for the open box slab and an illustrated picture of the structure:

Parameters for Kerto-Ripa -slabs are restricted as follows:

- Thickness of plates must meet conditions : T1 = 19…600 mm and T2 = 19…600 mm

- Width of the top plate: B ≤ 2520mm

- Minimum amount of web beams: 3 pcs, for a slab with a width of 2.5 meter

- For Kerto-Q top- and bottom-plate, a plates cantilever width can be max 20hf, where hf is the plates sanded thickness. This measure condition applies to parameters B11, B12, B21 and B22 for ribbed slabs and box slabs. Respective parameters for open box slabs are B11 and B12.

- For Kerto-S bottom plate, a plates cantilever width can be max 10hf, where hf is the plates grinded thickness. This measure condition applies to parameters B21 and B22 for open box slabs.

In Finnwood 2.4, it is possible to select a wooden panel with no composite action as a top plate for the Kerto-Ripa box slab. Smaller values to the strength and elastic modulus are set for this wooden panel, so it does not function as a part of the Kerto-Ripa elements cross-section. However, the specific weight of the material is taken into account in the calculation by a value of 5,0 kN/m3. Also, the user must ensure, that the selected wooden panel with no composite action meets the requirements for local stresses ( bending, shear force and deflection ).

finnwood 2.4 - metsawood.com · manual, program version and update checks can be found ......

Documents