Member Design for Timber Structures according to AS 1720 – 2010

General Information

Before you begin

Before you begin the design module, you will need to perform the following extra steps.

1. Import design code load combinations.
2. Assign design code load cases to the load groups in your model.

Design Specific Information

Suporte para versão atual

Seções

• Retangular
• Circular

Integrated section database of common sections for sawn timber, GluLam and LVL.

Materiais

• Sawn timber, seasoned and unseasoned
• GluLam
• Pole timber
• LVL (coming)

Integrated material database of sawn timber, GluLam and pole timber.

Começando

Detalhes

No Detalhes tab you can enter your project details so that they are displayed on your report, however they are not required.

Membros

DEFINITION: Design Member: a member, or group of connected members with the same section and material.

O Membros tab contains several tables:

1. O Membros Design tabela: Veja abaixo.
2. O Materiais Mesa: for your reference to review the materials used in your design.
3. O Seções Mesa: also for reference.

O Membros Design table allows you to add, remove and edit the design members deflection limit and parameters. If you are using the S3D integration version this information will be automatically filled with default values.

No Membros tab you can edit:

1. O ID de membro(s) campo: you can add multiple members to a single design member to simplify your design. Enter the member ids separated by commas.
2. O Def_eu campo: choose an appropriate deflection limit, this is required for calculating the deflection utility ratio.
3. O ID de parâmetro campo: the ID that links your design member to the Parâmetro table in the Parâmetros aba, read below for more information about setting parameters.

NOTA: Entering items like members or nodes as a comma separated list is a useful feature used widely in SkyCiv. Por exemplo: when modelling you can apply the same loads to multiple members by entering a comma separated list of the member ids in the ID de membro campo.

Parâmetros

Due to the number of parameters required for calculations in AS 1720, we’ve made it easier for you to enter them by creating a parameter table that links to the Membros Design tabela. If you have design members which are similar you don’t need to re-enter the same parameters for each one, just assign them the same Parameter ID.

O ID de parâmetro is entered in the Membros Design table under the Membros aba, Veja acima.

NOTA: The bulk of parameters have been hidden – to access them, Clique no editar icon under More Parameters heading.

No Parâmetros tab you can edit:

1. O k₄ campo: partial seasoning factor.
2. O k₆ drop-down: temperature factor.
3. O A seguir estão as diferentes maneiras de determinar os coeficientes de pressão de terra para calcular a resistência ao atrito unitária de estacas em areia drop-down: capacity factor.
4. O g₁₃ drop-down: fator de comprimento efetivo.
5. O Description campo: for your reference, does not appear in report.

When the edit icon is clicked is opened, you will see parameters are grouped:

1. O Intermediate Restraints aba: for bending and compression buckling.
2. O Pólo aba: para seções circulares.
3. O Strength Sharing aba: for bending checks on rectangular sections.
4. O Tensão aba: for bolted members.

Intermediate Restraints Parameters

If you would like to apply these parameters, please set the Aplicar toggle to on.

No Intermediate Restraints tab you can edit:

1. O Major Axis drop-down: type of restraint against major axis buckling.
2. O eu_ax campo: distance between discrete restraints.
3. O Minor Axis drop-down: type of restraint against minor axis buckling and lateral-torsional buckling.
4. O Minor Axis Position drop-down position of the restraint on the section, positive if the restraint is on the top edge of a normally orientated beam.
5. O eu_ay campo: the distance between discrete restraints, if the Minor Axis field is set to Discrete this is required.
6. O Fly Braces drop-down: partial restraint against lateral-torsional buckling.
7. O eu_a-φ campo: The distance between fly braces.

Pole Parameters

If you would like to apply these parameters, please set the Aplicar toggle to on.

On this tab you can edit:

1. O Species Class campo: for k₂₀ and k₂₁, the standard provides a method for calculating the values for Eucalypts and Corymbias, and Softwood. Other hardwoods must be estimated.
2. O j₉ campo: immaturity rigidity factor.
3. O k₂₀ campo: immaturity strength factor.
4. O k₂₁ drop-down: shaving factor.
5. O k_21b, k_21cl, k_21cp,v, e k_21t fields: shaving factors for various strength properties.
6. O k₂₂ drop-down: processing type.

Strength Sharing Parameters

If you would like to apply these parameters, please set the Aplicar toggle to on.

No Strength Sharing tab you can edit:

1. O Parallel System campo: choose a combination of discrete and combined.
2. O N_com drop-down: number of elements combined into a discrete unit.
3. O N_mem drop-down: number of discrete units the the system.
4. O Espaçamento campo: centre-to-centre spacing of discrete units.
5. O Comprimento do vão campo: effective span of the parallel members.

Tension Parameters

If you would like to apply these parameters, please set the Aplicar toggle to on.

No Tensão tab you can edit:

1. O Number of bolts campo: number of bolts at the critical cross-section.
2. O Bolt diameter campo: diameter of the bolts.
3. O Bolt hole tolerance field: tolerance.

NOTA: The calculation of A_n assumes that the bolts are through the smallest cross-section and are evenly spaced. It does not account for minimum spacing or edge distances.

Cargas

All materials are affected by creep (slow and minute increases over time of the deformation of an element under continuous load). Timber has a significant creep effect unlike other common construction materials like concrete and steel, timber creep is orders of magnitude more. This makes designing loads on timber structures somewhat more complicated, the duration of load needs to be considered for every load combination.

To account for this effect AS 1720 provides a factor for duration of load for strength (k₁) and guidance on the appropriate factors to use for load combinations from AS 1170. These are automatically filled into the load combinations parameters based on the load duration units select.

O Cargas tab contains:

1. O Força aba: for strength load combinations.
2. O Serviceability aba: for serviceability load combinations.
3. O Unallocated aba: user defined load combinations can be moved to either Força ou Serviceability guias.

NOTA: To allocate your custom load combinations, simple click the button for the load combination type you’d like to move it to. Após, review the load combination factors in the appropriate tab.

Força

No Força tab you can edit:

1. O Nome drop-down: select the name of the load combination to be displayed.
2. O Description campo: for reference, does not appear in report.
3. O Duration Units drop-down: segundos, minutos, horas, dias, months or decades, these correspond with the k₁ factor table.
4. O Nominal Load Modification Factor drop-down: Nenhum, short-term, longo prazo, terremoto, combination or custom.
5. O Nominal Load Modification Factors fields for each load group: to edit select the ‘custom’ de Nominal Load Modification Factor drop-down custom type, otherwise these will be automatically filled with AS 1170 valores.

Serviceability

No Serviceability tab you can edit:

1. O Nome drop-down: select the name of the load combination to be displayed.
2. O Description: not required, does not appear in report.
3. O Nominal Load Modification Factor drop down: Nenhum, short-term, longo prazo, terremoto, combination or custom.
4. The fields in the Greater than 1 Year, 5 Months, 5 Days and Less then 1 Dia colunas: these factors are proportions of the load case that is equal to the each respective load duration.

NOTA: Each factor load duration proportion must be ≤ 1 and the sum of all load duration proportions on each row must be ≤ 1.

Resultados

Once you have completed all of the above steps you can now check your design by clicking the Verificar Design botão. The software will alert you if you have missed any required fields, otherwise you will be taken to the Results tab.

No Resultados tab you have an overview of the utility ratios of the important checks in the design code in the Member Design Ratios tabela, if you’d like more detail you can click on the Design Summary button for a summary report.

In this member design module, individual reports are also available by clicking on the report icon in the Relatório column of the Member Design Ratios tabela.

Finalmente, you can see the overall governing results for each member by checking results displayed on the Wire-frame Model on the left.