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Manual

Timber ode heck


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Timber Code Check


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Table Of Contents

INTRODUCTION........................................................................................................ 1

PARAMETERS .......................................................................................................... 3

Material properties 3

Timber parameters 3

Adjusting the parameters for design 5

CODE CHECK ........................................................................................................... 7

Performing the check 7

Detailed check 7

OPTIMISATION.......................................................................................................... 9

Introduction to optimisation 9

Principles of optimisation 9

Optimisation parameters 9

Optimising the members 10


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Introduction

The ESA PT Timber Code Check module is a program for the design of timber structures. It consists of stressand stability verifications of timber members according to the code. It is also possible to search interactively forthe lightest section, which meets the code requirements for selected loadings (optimisation).

The following structural timber design codes are supported : Eurocode 5.

For more details about the used codes and the theoretical background, we refer to the Theoretical Backgroundmanual and to the code itself.

IMPORTANT: Only straight beams can be checked. The solution for curved beams is notimplemented.


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3

Parameters

Material properties

In addition to standard material properties, there are a few extra parameters related to the code check.

Bending (fm, k) characteristic value of bending strength

Tension (ft, 0, k) characteristic value of tensile strength parallel to grain

Tension (ft, 90, k) characteristic value of tensile strength perpendicular tograin

Compression (fc, 0, k) characteristic value of compressive strength parallel tograin

Compression (fc, 90, k) characteristic value of compressive strengthperpendicular to grain

Shear (fv, k) characteristic value shear strength

Modulus (E0.05) 5-percentile characteristic value of modulus of elasticityparallel to grain

Modulus (E 90 mean) mean characteristic value of modulus of elasticityperpendicular to grain

Type of timber Solid or Glued, laminated type can be selected.

Procedure to adjust material properties

1. Open the Material manager, e.g. through the tree menu function Library > Materials.

2. Select the required material.

3. Press button [Edit].

4. Fill in the parameters under group EC5.

5. Close the editing dialogue.

6. Close the Material manager.

Timber parameters

Gamma m, settings NAD

Ultimate limit states

These parameters represent the box values from EC5, table 2.3.3.2.

fundamental combinations:

timber and wood-based

materials

Specifies gamma m for fundamental combinations:timber and wood-based materials.

fundamental combinations:

steel used in joints

Specifies gamma m fundamental combinations: steelused in joints.

accidental combinations Specifies gamma m accidental combinations.

Serviceability limit states

serviceability coeff.

(title not shown)

The coefficient for serviceability combinations.

Interaction buckling - LTB

No interaction No interaction between buckling and lateral torsional

buckling is performed. Only the separate checksaccording to EC5 are executed.

According to CSN NAD Interaction between buckling and lateral torsional


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buckling according to the CSN NAD is performed: theLTB is checked for the moment around the major axis,together with the buckling influence.

According to DIN NAD Interaction between buckling and lateral torsionalbuckling according to the DIN NAD is performed: theLTB is checked for the moments around both axis,

together with the buckling influence.

Default sway types

This setting will be used for the beams where no detailed adjustment of buckling parameters is made.

The sway type is used to calculate the buckling length coefficients for flexural buckling, it has no effect ondefined buckling length ratios.

Buckling length ratios ky, kz

As input The program will always use the input values.

Calculated The program will use the calculated ky and kz factorsand neglect all input values.

Calculated only if no input

value

The program uses the input values of coefficients if thecoefficients values were defined.

The program uses the calculated values if thecoefficients values were NOT defined or if their vaulewas set to 1 (minus one).

Bigger of input and calculated Program takes the greater of the two available values i.e. the less favourable value.

Smaller of input and

calculated

Program takes the smaller of the two available values i.e. the more favourable value.

Max. k ratio The calculated value of k will be limited to this value.

Max. slenderness If the slenderness of the checked member exceeds thisvalue, the program will print a warning in the output.

Check bounds

Individual results of checks for timber members are divided into three groups in accordance with the standard:

unused unity check lower than the lower limit

optimal unity check between the lower and upper limit

non-satisfying unity check greater than the upper limit

The items in Check boundsgroup can be used to set the lower and upper limit. The default values are 0.25for the lower limit and 1.0 for the upper limit.

Once the calculation is performed and the results drawn in the graphical window, the adjusted limits control thecolour of result diagram.

Service class setting

1 Class 1 is characterized by a moisture content in thematerials corresponding to a temperature of 20C andthe relative humidity of the surrounding air onlyexceeding 65% for a few weeks per year.

2 Class 2 is characterized by a moisture content in the

materials corresponding to a temperature of 20C andthe relative humidity of the surrounding air only


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exceeding 85% for a few weeks per year.

3 Class 3 climatic conditions leading to higher moisturecontents than in service class 2.

k mod, k def

For each selected service classyou can specify the modification factors k mod depending on the material(Solidand glued laminated timber, Plywood) and the load duration class (permanent, long-term, medium-term,short termandinstantaneous). (See EC5, table 3.1.7).

For each selected service class you can specify the factors k def depending on the material and the loadduration class (See EC5, table 4.1).

The factor k def is a factor which takes into account the increase in deformation over time due to the combinedeffect of creep and moisture.

The load-duration classes are characterized by the effect of a constant load acting for a certain period of timein the life of the structure.

Load duration class Time of duration Examples

permanent more than 10 years self-weight

long-term 6 months - 10 years storage

medium-term 1 week 6 months imposed loads

short-term less than one week snow, wind

instantaneous accidental loads

The load duration class is defined during the input of the load cases.

Adjusting the parameters for design

The user must review and adequately adjust a set of design and calculation parameters prior to performing a

successful and accurate design and checking of a timber member. All the parameters that may be adjusted areintegrated into one modal dialogue.

The procedure for modifying parameters

1. Call tree menu function Timber > Setup.

2. The Setup dialogue opens on the screen.

3. Select the required parameter set.

4. Input desired values.

5. Confirm the settings with [OK].


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Code check

Performing the check

The procedure to perform the check

1. Open service Timber.

2. Select function Check (single click on the function is sufficient to invoke the function).

3. Select the required type of load.

4. Select the required load case, combination or class.

5. Select beams to be checked.

6. Select the required quantity and if required, make other adjustments in the property window.

7. Click Action button[Refresh]to see the selected design values.

8. Repeat steps 3 to 7 as many times as required.

IMPORTANT: Only straight beams can be checked. The solution for curved beams is notimplemented.

Detailed check

If required, a selected member can be checked in detail. To do so, press button [Single check]in the Actionbar of function Check.

Single cross-section dialogue provides for detailed view of design results.

Text window

This window contains the results of the check for the selected member presented in tabular form.

Graphical window

A simple result diagram is drawn here.

Next/Previous buttons

You may use these buttons to select other members from the project.

View selection

It is possible to view in the text window either the report on the check or a table of internal forces (effects).

Procedure to perform the detailed check


2. Select function Check (single click on the function is sufficient to invoke the function).

3. Select the required type of load.

4. Select the required load case, combination or class.

5. Press action button [Single check].

6. Select the beam to be checked.

7. The Single check dialogue is opened on the screen.


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Optimisation

Introduction to optimisation

Once a structure has been designed and calculated, it is the time to perform checking and usually a kind of

optimisation of the original design.SCIA.ESA PT contains a powerful tool for this task. The optimisation of applied profiles may be doneautomatically or semi-automatically. The process of optimisation results in what may be called an economicaland good solution.

The optimisation process in SCIA.ESA PT is based on assumptions given in the following chapter.

Principles of optimisation

An optimisation in general represents a complex task. A full, complete and really "optimal" optimisation wouldusually lead to a long and often recursive process. Therefore, SCIA.ESA PT implements a kind of compromise.

One optimisation step takes account of a single cross-section only

It is possible to optimise one cross-section at a time. The user selects the cross-section from a list of all cross-sections applied in the structure.

One optimisation step considers only selected members

It is possible to limit the optimisation process to only a selected set of members. The user may make aselection to specify which beams of the given cross-section should be considered for the optimisationcalculations.

One optimisation step affects the whole structure

Once the optimised cross-section is found, it is applied to ALL members in the structure that are of thespecified cross-section. It is of no importance whether the optimisation calculation was limited to a selectednumber of beams or not. The final effect of the optimisation is that the original cross-section is simply replacedwith the new, i.e. optimised, cross-section.

Optimisation parameters

The user may control the process of optimisation by means of a set of parameters.

Check parameter

Maximal check This parameter tells the program what is the maximal allowablevalue for satisfactory checking.

Maximum unity check This item shows the found maximal check result for theoptimised cross-section.

Shape parameters for optimisation

Dimension This item determines which of the dimensions of the cross-section should be optimised. All other dimensions remainunchanged.

Step This item specifies the step by which the selected dimension idmodified in order to give one-step smaller or larger cross-section.

Minimum This item specifies the minimal size of the selected dimension.

Maximum This item specifies the maximal size of the selected dimension.

Buttons for manual optimisation

Set value This button enables the user to set manually the required value


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of selected dimension (see above).

Next down This button finds one-step smaller cross-section according todefined shape parameters (see above).

Next up This button finds one-step larger cross-section according todefined shape parameters (see above).

Buttons for automatic optimisation

Search for optimal This button finds automatically the optimal cross-section.

Optimising the members

It is possible to perform both automatic and manual optimisation. The process for both is identical except thelast but one step. Therefore, only one procedure will be given here in detail. The other one will be explainedbriefly.

Procedure for the automatic optimisation of members


2. Select function Check.

3. In the Property window, go to itemFilter

and set it toCross-section

.

4. In the Property window, go to item Cross-section and select the one you want to optimise.

5. In the Property window, go to item Selection and set it to User or All, depending on yourrequirements.

6. If the item is set to User, make the selection and press button [Esc] to close the selection.

7. If the item Selectionhas been re-adjusted, press button [Redraw] in order to refresh the screenand see the appropriate display.

8. In the Property window, go to item Optimisation and press the button there.

9. The optimisation dialogue is opened on the screen.

10. Adjust the parameters as required.

11. Press button [Search for optimal]. The program finds the optimal cross-section.

12. If you agree, press [OK] to confirm.

Procedure for the manual optimisation of members

The procedure is identical except step 11.

In manual optimisation, the user must press (repeatedly, if required) buttons [Next down] and [Next Up], inorder to find the optimal cross-section. Alternatively, it is also possible to set the required value directly bymeans of button [Set value].

Note: The project must be calculated beforehand.

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